Study of a new glass matrix by thermoluminescent technique for high-dose dosimetry

Energy Technology Data Exchange (ETDEWEB)

Ferreira, Pamela Z.; Carvalho, Gabriel S. Marchiori de; Cunha, Diego M. da; Dantas, Noelio O.; Silva, Anielle C.A.; Neves, Lucio P.; Perini, Ana P., E-mail: anapaula.perini@ufu.br [Universidade Federal de Uberlandia (UFU), MG (Brazil). Instituto de Fisica; Linda, V.E. Caldas [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil); Carrera, Betzabel N.S.; Watanabe, Shigueo [Universidade de Sao Paulo (IF/USP), Sao Paulo, SP (Brazil). Instituto de Fisica

2016-07-01

The thermoluminescence technique is widely used for both personal and for high-dose dosimetry. In this work, the thermoluminescence technique was utilized to study a new glass matrix, with nominal composition of 20Li{sub 2}CO{sub 3}.10Al{sub 2}O{sub 3}.30BaO.40B{sub 2}O{sub 3} (mol%), irradiated with different doses in a {sup 60}Co source. The glow curves and the dose-response curve were obtained for radiation doses of 10, 50, 100, 200 e 700 Gy. The results showed that this new glass matrix has potential use in high-dose dosimetry. (author)

Investigation of PBAT dosimetric properties for high gamma dose dosimetry

International Nuclear Information System (INIS)

Cunha, Elisete L.; Schimitberger, Thiago

2017-01-01

Poly(butylene adipate-co-terephthalate) (PBAT) is an aliphatic-aromatic copolyester which is biodegradable. It is a non-photoluminescent copolyester that becomes photoluminescent after previous exposure to gamma doses higher than 100 kGy. After the previous high energy irradiation, the material shows the highest photo-stimulated luminescence emission when excited with a LED source at wavelengths ranging from 370 to 405 nm. In this work we investigated the enhancement of the photoluminescence (PL) and dosimetric properties of PBAT, after exposure to high doses of gamma radiation ranging from 50 to 4,000 kGy. In this investigation we demonstrate that increasing the PBAT film thickness by 100 μm enhances the PL output by 3.5 times, when irradiated with 500 kGy. Also, besides the already known color green brightness, the PL intensity can also be used for high dose dosimetry purposes for doses ranging from 50 to 750 kGy. The FTIR analysis has demonstrated that the there is a linear relationship between peak intensity and dose for doses ranging from 100 and 2,000 kGy for the absorbance peaks at 3,241 cm -1 and 3271 cm -1 , with linear correlation coefficients of 0.9981 and 0.9992, respectively. The results indicate that PBAT has great potential for applications in bio-imaging devices and high gamma dose dosimetry. (author)

Investigation of PBAT dosimetric properties for high gamma dose dosimetry

Energy Technology Data Exchange (ETDEWEB)

Cunha, Elisete L.; Schimitberger, Thiago, E-mail: elisete.cunha@cdtn.br [Universidade Federal de Minas Gerais (UFMG), Belo Horizonte, MG (Brazil). Departamento de Engenharia Nuclear; Oliveira, Cristiana M.; Faria, Luiz O., E-mail: farialo@cdtn.br [Centro de Desenvolvimento da Tecnologia Nuclear (CDTN/CNEN-MG), Belo Horizonte, MG (Brazil)

2017-07-01

Poly(butylene adipate-co-terephthalate) (PBAT) is an aliphatic-aromatic copolyester which is biodegradable. It is a non-photoluminescent copolyester that becomes photoluminescent after previous exposure to gamma doses higher than 100 kGy. After the previous high energy irradiation, the material shows the highest photo-stimulated luminescence emission when excited with a LED source at wavelengths ranging from 370 to 405 nm. In this work we investigated the enhancement of the photoluminescence (PL) and dosimetric properties of PBAT, after exposure to high doses of gamma radiation ranging from 50 to 4,000 kGy. In this investigation we demonstrate that increasing the PBAT film thickness by 100 μm enhances the PL output by 3.5 times, when irradiated with 500 kGy. Also, besides the already known color green brightness, the PL intensity can also be used for high dose dosimetry purposes for doses ranging from 50 to 750 kGy. The FTIR analysis has demonstrated that the there is a linear relationship between peak intensity and dose for doses ranging from 100 and 2,000 kGy for the absorbance peaks at 3,241 cm{sup -1} and 3271 cm{sup -1}, with linear correlation coefficients of 0.9981 and 0.9992, respectively. The results indicate that PBAT has great potential for applications in bio-imaging devices and high gamma dose dosimetry. (author)

Radiation processing and high-dose dosimetry at ANSTO

International Nuclear Information System (INIS)

Gant, G.J.; Saunders, M.; Banos, C.; Mo, L.; Davies, J.; Evans, O.

2001-01-01

The Radiation Technology group at ANSTO is part of the Physics Division and provides services and advice in the areas of gamma irradiation and high-dose dosimetry. ANSTO's irradiation facilities are designed for maximum dose uniformity and provide a precision irradiation service unique in Australia. Radiation Technology makes and sells reference and transfer standard dosimeters which are purchased by users and suppliers of commercial irradiation services in Australia and the Asia-Pacific region. A calibration service is also provided for dosimeters purchased from other suppliers

Evaluation of glasses containing cadmium for high dose dosimetry by the thermoluminescence technique

International Nuclear Information System (INIS)

Carvalho, Gabriel Soares Marchiori de; Ferreira, Pamela Zati; Cunha, Diego Merigue da; Dantas, Noelio Oliveira; Silva, Anielle C.A.; Perini, Ana Paula; Neves, Lucio Pereira; Carrera, Betzabel Noemi Silva; Watanabe, Shigueo

2016-01-01

New glass matrices were evaluated for high dose dosimetry by the thermoluminescence technique. Their nominal composition are 20Li_2CO_3.10Al_2O_3.15CdO.55B_2O_3 and 20Li_2CO_3.10Al_2O_3.20CdO.50B_2O_3 (mol%). The glass matrices were irradiated with different doses: 50, 100, 200, 500, 700 and 900 Gy, and the thermoluminescence emission curves were obtained for each of these values. The results show a great potential of using these matrices in high dose dosimetry. (author)

Clinical dosimetry with plastic scintillators - Almost energy independent, direct absorbed dose reading with high resolution

Energy Technology Data Exchange (ETDEWEB)

Quast, U; Fluehs, D [Department of Radiotherapy, Essen (Germany). Div. of Clinical Radiation Physics; Fluehs, D; Kolanoski, H [Dortmund Univ. (Germany). Inst. fuer Physik

1996-08-01

Clinical dosimetry is still far behind the goal to measure any spatial or temporal distribution of absorbed dose fast and precise without disturbing the physical situation by the dosimetry procedure. NE 102A plastic scintillators overcome this border. These tissue substituting dosemeter probes open a wide range of new clinical applications of dosimetry. This versatile new dosimetry system enables fast measurement of the absorbed dose to water in water also in regions with a steep dose gradient, close to interfaces, or in partly shielded regions. It allows direct reading dosimetry in the energy range of all clinically used external photon and electron beams, or around all branchytherapy sources. Thin detector arrays permit fast and high resolution measurements in quality assurance, such as in-vivo dosimetry or even afterloading dose monitoring. A main field of application is the dosimetric treatment planning, the individual optimization of brachytherapy applicators. Thus, plastic scintillator dosemeters cover optimally all difficult fields of clinical dosimetry. An overview about its characteristics and applications is given here. 20 refs, 1 fig.

TL response of citrine samples for high-dose dosimetry

International Nuclear Information System (INIS)

Teixeira, Maria Ines; Caldas, Linda V.E.

2011-01-01

The possibility of using samples of Brazilian stones as quartz, amethyst, topaz, etc. for high-dose dosimetry has been studied in recent years at IPEN, using the thermoluminescence technique (TL). In this work, the TL properties of citrine samples were studied. They were exposed to different doses of gamma radiation ( 60 Co). The natural citrine stone was extracted from a mine in Minas Gerais state, Brazil; it is a tectosilicate ranked as one of three-dimensional structure, showing clear yellow to golden brown color. The natural citrine stone is classified as quartz (SiO 2 ), and it has a lower symmetry and more compact reticulum. The citrine stone samples were powdered, and the selected grains were mixed with Teflon in the proportion 2 (Teflon):1 (Citrine). The mixture was pressed and sintered for production of Citrine -Teflon pellets of 50 mg. The TL emission curve showed two peaks at 160 deg C and 220 deg C. To remove the TL peak (160 deg C) of the sintered citrine pellet glow curves, different thermal treatments were tested during several time intervals. The TL dose-response curve between 50 Gy and 100 kGy, the reproducibility of TL response and the lower detection dose were obtained. The preliminary results show that citrine may be useful for high-dose dosimetry. (author)

Techniques for high dose dosimetry in industry, agriculture and medicine. Proceedings of a symposium

Energy Technology Data Exchange (ETDEWEB)

NONE

1999-03-01

In radiation processing, it is important that the irradiated products are reliable and safe. For processes that impact directly on public health, dosimetry provides a formal means of regulation. For other applications, measurements are indispensable for process control to improve quality and the measurements have to be standardized. Thus, dosimetry is an essential part of quality standards for radiation processes. In the developing world, establishment of such quality standards is only in the embryonic stage, and the IAEA should and does play a role in the development and implementation of these standards. The IAEA initiated a programme of high dose dosimetry in 1977 to accomplish dose standardization on an industrial scale, to promote dosimetry as a quality control measure in radiation processing, and to help develop new dosimetry techniques. Since dosimetry has such a key role in these processes, the IAEA organized this international symposium to provide a forum for presentation and discussion of up-to-date developments in this field. Since the International Symposium on High Dose Dosimetry for Radiation Processing held in 1990 the field of dosimetry has deepened and broadened. There is a definite shift towards quality assurance, which calls for dependable dosimetry systems with well established traceability to national or international standards. Also, many new applications of radiation have been developed and for these new and innovative dosimetry methods are needed. This symposium has provided a forum for the discussion of many of these developments and consideration of the outstanding issues in these vital areas Refs, figs, tabs

Techniques for high dose dosimetry in industry, agriculture and medicine. Proceedings of a symposium

International Nuclear Information System (INIS)

1999-03-01

In radiation processing, it is important that the irradiated products are reliable and safe. For processes that impact directly on public health, dosimetry provides a formal means of regulation. For other applications, measurements are indispensable for process control to improve quality and the measurements have to be standardized. Thus, dosimetry is an essential part of quality standards for radiation processes. In the developing world, establishment of such quality standards is only in the embryonic stage, and the IAEA should and does play a role in the development and implementation of these standards. The IAEA initiated a programme of high dose dosimetry in 1977 to accomplish dose standardization on an industrial scale, to promote dosimetry as a quality control measure in radiation processing, and to help develop new dosimetry techniques. Since dosimetry has such a key role in these processes, the IAEA organized this international symposium to provide a forum for presentation and discussion of up-to-date developments in this field. Since the International Symposium on High Dose Dosimetry for Radiation Processing held in 1990 the field of dosimetry has deepened and broadened. There is a definite shift towards quality assurance, which calls for dependable dosimetry systems with well established traceability to national or international standards. Also, many new applications of radiation have been developed and for these new and innovative dosimetry methods are needed. This symposium has provided a forum for the discussion of many of these developments and consideration of the outstanding issues in these vital areas

Evaluation of glasses containing cadmium for high dose dosimetry by the thermoluminescence technique

Energy Technology Data Exchange (ETDEWEB)

Carvalho, Gabriel Soares Marchiori de; Ferreira, Pamela Zati; Cunha, Diego Merigue da; Dantas, Noelio Oliveira; Silva, Anielle C.A.; Perini, Ana Paula; Neves, Lucio Pereira, E-mail: lucio.neves@ufu.br [Universidade Federal de Uberlandia (INFIS/UFU), MG (Brazil). Instituto de Fisica; Caldas, Linda V.E. [Instituto de Pesquisas Energeticas e Nucleares (IPEN-CNEN/SP), Sao Paulo, SP (Brazil); Carrera, Betzabel Noemi Silva; Watanabe, Shigueo [Universidade de Sao Paulo (IF/USP), SP (Brazil). Instituto de Fisica

2016-07-01

New glass matrices were evaluated for high dose dosimetry by the thermoluminescence technique. Their nominal composition are 20Li{sub 2}CO{sub 3}.10Al{sub 2}O{sub 3}.15CdO.55B{sub 2}O{sub 3} and 20Li{sub 2}CO{sub 3}.10Al{sub 2}O{sub 3}.20CdO.50B{sub 2}O{sub 3} (mol%). The glass matrices were irradiated with different doses: 50, 100, 200, 500, 700 and 900 Gy, and the thermoluminescence emission curves were obtained for each of these values. The results show a great potential of using these matrices in high dose dosimetry. (author)

Dosimetry in Interventional Radiology - Effective Dose Estimation

International Nuclear Information System (INIS)

Miljanic, S.; Buls, N.; Clerinx, P.; Jarvinen, H.; Nikodemova, D.; Ranogajec-Komor, M; D'Errico, F.

2008-01-01

Interventional radiological procedures can lead to significant radiation doses to patients and to staff members. In order to evaluate the personal doses with respect to the regulatory dose limits, doses measured by dosimeters have to be converted to effective doses (E). Measurement of personal dose equivalent Hp(10) using a single unshielded dosimeter above the lead apron can lead to significant overestimation of the effective dose, while the measurement with dosimeter under the apron can lead to underestimation. To improve the accuracy, measurements with two dosimeters, one above and the other under the apron have been suggested ( d ouble dosimetry ) . The ICRP has recommended that interventional radiology departments develop a policy that staff should wear two dosimeters. The aim of this study was to review the double dosimetry algorithms for the calculation of effective dose in high dose interventional radiology procedures. The results will be used to develop general guidelines for personal dosimetry in interventional radiology procedures. This work has been carried out by Working Group 9 (Radiation protection dosimetry of medical staff) of the CONRAD project, which is a Coordination Action supported by the European Commission within its 6th Framework Program.(author)

High doses dosimetry in irradiation process in Argentine

International Nuclear Information System (INIS)

Dorda de Cancio, E.M.

1997-01-01

These report describes the lung dose dosimetry procedures of the Semi-Industrial Irradiation Plant in Ezeisa Atomic (500,00 Ci of Co 60) and Industrial Picorrad Plant (400,00 Ci of Co 60) using the nitrate dosimeter

Teflon pastille use in high dose dosimetry; Utilizacao de pastilhas de teflon em dosimetria de doses altas

Energy Technology Data Exchange (ETDEWEB)

Teixeira, Maria Ines [Associacao Educacional Nove de Julho (UNINOVE), Sao Paulo, SP (Brazil); Caldas, Linda V.E., E-mail: miteixeira@ipen.b, E-mail: lcaldas@ipen.b [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil)

2011-10-26

This paper study the Teflon, which is used as aglomerant in the confection of dosimetric pastilles, for the viabilization of this material as high dose dosimeter. This paper used the OSL technique for the characterization of dosimetric properties of Teflon. The doses-response curve has been obtained for {sup 60}Co radiation between 100 Gy and 50 kGy, and the OSL answer reproducibility. The preliminary results shown that the Teflon is a material which can be used for high dose dosimetry

Monte Carlo dosimetry of the IRAsource high dose rate 192Ir brachytherapy source

International Nuclear Information System (INIS)

Sarabiasl, Akbar; Ayoobian, Navid; Jabbari, Iraj; Poorbaygi, Hossein; Javanshir, Mohammad Reza

2016-01-01

High-dose-rate (HDR) brachytherapy is a common method for cancer treatment in clinical brachytherapy. Because of the different source designs, there is a need for specific dosimetry data set for each HDR model. The purpose of this study is to obtain detailed dose rate distributions in water phantom for a first prototype HDR 192 Ir brachytherapy source model, IRAsource, and compare with the other published works. In this study, Monte Carlo N-particle (MCNP version 4C) code was used to simulate the dose rate distributions around the HDR source. A full set of dosimetry parameters reported by the American Association of Physicists in Medicine Task Group No. 43U1 was evaluated. Also, the absorbed dose rate distributions in water, were obtained in an along-away look-up table. The dose rate constant, Λ, of the IRAsource was evaluated to be equal to 1.112 ± 0.005 cGy h −1 U −1 . The results of dosimetry parameters are presented in tabulated and graphical formats and compared with those reported from other commercially available HDR 192 Ir sources, which are in good agreement. This justifies the use of specific data sets for this new source. The results obtained in this study can be used as input data in the conventional treatment planning systems.

Study of the response reduction of LiF:Mg, Ti dosimeter for high dose dosimetry

Energy Technology Data Exchange (ETDEWEB)

Torkzadeh, Falamarz [Nuclear Sciences and Technology Research Institute, Tehran (Iran, Islamic Republic of). Radiation Applications Research School; AEOI, Tehran (Iran, Islamic Republic of); Faripour, Heidar [Nuclear Sciences and Technology Research Institute, Tehran (Iran, Islamic Republic of). Laser and Optics Research School; AEOI, Tehran (Iran, Islamic Republic of); Mardashti, Forough; Manouchehri, Farhad [Nuclear Sciences and Technology Research Institute, Tehran (Iran, Islamic Republic of). Radiation Applications Research School

2017-07-15

A single crystal and 5 polycrystalline samples of LiF:Mg, Ti and their pellets were prepared and investigated so as to apply thermoluminescence high gamma dose dosimetry. Three zones of single crystal with dopant concentrations of 200 ppm of Mg and 20 ppm of Ti were also used to prepare the single crystal samples. For polycrystalline samples, dopant concentrations of 0.062 mol% Mg and Ti concentrations in the range of 0.016 and 0.046 mol% were used. All the samples were exposed to gamma doses of 1 kGy to 700 kGy and their response changes were determined by a gamma dose test of about 60 mGy. According to the results obtained, the use of response reduction by curve-fitting up to about 300 kGy can be performed reliably for high dose gamma dosimetry.

Three-dimensional high dose rate dosimetry of electron beams. A combined radiochromic film, EPR and calorimetric dosimetry

International Nuclear Information System (INIS)

Secerov, B.; Milosavljevic, B.H.; Bacic, G.; Belgrade Univ.

2002-01-01

Complete text of publication follows. Aim. To examine the suitability of radiochromic film (RCF) dosimeters in determining 3D dose distribution from a pulsed electron beam source by comparing their response with alanine EPR dosimetry and calorimetry. Experimental. A FWT-60 radiochromic films (Far West Technology Inc) were used while alanine films were home made. To obtain the dose vs. penetration depth relationship, a stack of 13 films separated by aluminium plates and/or alanine films was placed perpendicular to the electron beam (Febetron, 20 ns, 1.8 MeV, 10 12 Gy/s, dose range up to 100 kGy). RC films were calibrated using 60-Co source and Fricke dosimetry. The absorbance of irradiated films was measured using 2D microdensitometry. Calorimetry was performed with a homemade quasy-adiabatic aluminum calorimeter. Results and Discussion. Microdensitometry of films (5 x 5 cm) enabled the 3D mapping of the entire radiation field with in plane resolution of 0.12 mm. The total dose for each film was obtained by image segmentation to correct for the non-linear response of films. Integrated dose for the entire stack was in good agreement (within 5%) with total absorbed energy as determined with calorimetry. The dose distribution along the beam center was determined using alanine films (1 x 1 cm) and EPR spectroscopy, and again a good agreement with the dose determined by microdensitometry of the central portion of RC films. In conclusion, the results indicate that RC films can be used for determination of 3D dose distribution even at very high dose rates

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

International Nuclear Information System (INIS)

Ansbacher, W.

1996-01-01

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

High dose-per-pulse electron beam dosimetry: Usability and dose-rate independence of EBT3 Gafchromic films.

Science.gov (United States)

Jaccard, Maud; Petersson, Kristoffer; Buchillier, Thierry; Germond, Jean-François; Durán, Maria Teresa; Vozenin, Marie-Catherine; Bourhis, Jean; Bochud, François O; Bailat, Claude

2017-02-01

The aim of this study was to assess the suitability of Gafchromic EBT3 films for reference dose measurements in the beam of a prototype high dose-per-pulse linear accelerator (linac), capable of delivering electron beams with a mean dose-rate (Ḋ m ) ranging from 0.07 to 3000 Gy/s and a dose-rate in pulse (Ḋ p ) of up to 8 × 10 6 Gy/s. To do this, we evaluated the overall uncertainties in EBT3 film dosimetry as well as the energy and dose-rate dependence of their response. Our dosimetric system was composed of EBT3 Gafchromic films in combination with a flatbed scanner and was calibrated against an ionization chamber traceable to primary standard. All sources of uncertainties in EBT3 dosimetry were carefully analyzed using irradiations at a clinical radiotherapy linac. Energy dependence was investigated with the same machine by acquiring and comparing calibration curves for three different beam energies (4, 8 and 12 MeV), for doses between 0.25 and 30 Gy. Ḋ m dependence was studied at the clinical linac by changing the pulse repetition frequency (f) of the beam in order to vary Ḋ m between 0.55 and 4.40 Gy/min, while Ḋ p dependence was probed at the prototype machine for Ḋ p ranging from 7 × 10 3 to 8 × 10 6 Gy/s. Ḋ p dependence was first determined by studying the correlation between the dose measured by films and the charge of electrons measured at the exit of the machine by an induction torus. Furthermore, we compared doses from the films to independently calibrated thermo-luminescent dosimeters (TLD) that have been reported as being dose-rate independent up to such high dose-rates. We report that uncertainty below 4% (k = 2) can be achieved in the dose range between 3 and 17 Gy. Results also demonstrated that EBT3 films did not display any detectable energy dependence for electron beam energies between 4 and 12 MeV. No Ḋ m dependence was found either. In addition, we obtained excellent consistency between films and TLDs over the entire Ḋ p

Dosimetry for radiation processing. Final report of the co-ordinated research project on characterization and evaluation of high dose dosimetry techniques for quality assurance in radiation processing

International Nuclear Information System (INIS)

2000-06-01

In many Member States the use of large cobalt-60 gamma ray facilities and electron beam accelerators with beam energies from about 0.1 to 10 MeV for industrial processing continues to increase. For these processes, quality assurance relies on the application of well established dosimetry systems and procedures. This is especially the case for health regulated processes, such as the radiation sterilization of health care products, and the irradiation of food to eliminate pathogenic organisms or to control insect pests. A co-ordinated research project (CRP) was initiated by the IAEA in June 1995. Research contracts and research agreements in areas of high dose dosimetry were initiated to meet these challenges. The major goals of this CRP were to investigate the parameters that influence the response of dosimeters and to develop reference and transfer dosimetry techniques, especially for electron beams of energy less than 4 MeV and for high energy X ray sources (up to 5 MV). These will help to unify the radiation measurements performed by different radiation processing facilities and other high dose dosimetry users in Member States and encourage efforts to obtain traceability to primary and secondary standards laboratories. It will also aim to strengthen and expand the present International Dose Assurance Service (IDAS) provided by the IAEA

Measurement of absorbed doses near interfaces, and dose mapping using gas chromic dosimetry media. Vol. 2

Energy Technology Data Exchange (ETDEWEB)

Abdel-Rehim, F; Said, F I.A.; Abdel-Fattah, A A [National Centre for Radiation Research and Technology, Atomic Energy Athority, P.O.Box 29 Nasr City, Cairo (Egypt)

1996-03-01

Gas chromic dosimetry media is a thin-coated film which has advantages for high-dose radiation dosimetry, and produces high-resolution radiation image for gamma radiation. Therefore, these films were calibrated for the dose range 0.1-50 kGy in terms of increase in absorbance at 600 nm, 400 nm; increase in the area of the absorption spectra in the ranges 395-405 nm and 320-450 nm wave length as a function of absorbed dose in water. The calibrated films were used for measurement of absorbed doses close to metal interface, and dose mapping of the radiation field inside product box during a run for sterilizing surgical gloves at the mega-gamma irradiation facility.7 figs.

Plastic film materials for dosimetry of very large absorbed doses

DEFF Research Database (Denmark)

McLaughlin, W.L.; Miller, Arne; Abdel-Rahim, F.

1985-01-01

Most plastic films have limited response ranges for dosimetry because of radiation-induced brittleness, degradation, or saturation of the signal used for analysis (e.g. spectrophotometry) at high doses. There are, however, a few types of thin plastic films showing linearity of response even up...... to doses as high as 2 × 106 Gy (200 Mrad) without severe loss of mechanical properties. Among many candidate film types tested, those showing such resistance to radiation damage and continued response at such high doses are polyethylene terephthalate, high-density polyethylene, dyed polyvinylchloride......, the dyed polychlorostyrenes show essentially the same response to radiation-processing gamma-ray fields and to very high-intensity electron beams, and a relatively stable absorption spectrum at wavelengths for dosimetry analysis in the visible spectral region of ≈430 nm....

Dosimetry of high energy radiation

CERN Document Server

Sahare, P D

2018-01-01

High energy radiation is hazardous to living beings and a threat to mankind. The correct estimation of the high energy radiation is a must and a single technique may not be very successful. The process of estimating the dose (the absorbed energy that could cause damages) is called dosimetry. This book covers the basic technical knowledge in the field of radiation dosimetry. It also makes readers aware of the dangers and hazards of high energy radiation.

Development of transmission dose estimation algorithm for in vivo dosimetry in high energy radiation treatment

International Nuclear Information System (INIS)

Yun, Hyong Geun; Shin, Kyo Chul; Hun, Soon Nyung; Woo, Hong Gyun; Ha, Sung Whan; Lee, Hyoung Koo

2004-01-01

In vivo dosimetry is very important for quality assurance purpose in high energy radiation treatment. Measurement of transmission dose is a new method of in vivo dosimetry which is noninvasive and easy for daily performance. This study is to develop a tumor dose estimation algorithm using measured transmission dose for open radiation field. For basic beam data, transmission dose was measured with various field size (FS) of square radiation field, phantom thickness (Tp), and phantom chamber distance (PCD) with a acrylic phantom for 6 MV and 10 MV X-ray. Source to chamber distance (SCD) was set to 150 cm. Measurement was conducted with a 0.6 cc Farmer type ion chamber. By using regression analysis of measured basic beam data, a transmission dose estimation algorithm was developed. Accuracy of the algorithm was tested with flat solid phantom with various thickness in various settings of rectangular fields and various PCD. In our developed algorithm, transmission dose was equated to quadratic function of log(A/P) (where A/P is area-perimeter ratio) and the coefficients of the quadratic functions were equated to tertiary functions of PCD. Our developed algorithm could estimate the radiation dose with the errors within ±0.5% for open square field, and with the errors within ±1.0% for open elongated radiation field. Developed algorithm could accurately estimate the transmission dose in open radiation fields with various treatment settings of high energy radiation treatment. (author)

Polycarbonate-based benzo-δ-sultam films for high-dose dosimetry in radiation processing

International Nuclear Information System (INIS)

Feizi, Shazad; Nuclear Science and Technology Research Institute, Tehran; Ziaie, Farhood; Ghandi, Mehdi

2015-01-01

In this work characteristics of the polycarbonate films with 20 μm in thickness containing different weight percentage of Benzo-δ-sultam were studied for use as a high dose dosimetry system in radiation processing facilities. The sensitivity of the dosimeters and the linearity of dose-response curves were investigated under 60 Co γ-rays in a dose range of 0-100 kGy, and obtained results were compared with the commercial CTA and FWT film dosimeters. The results show that the absorbance at 348 nm depends linearly on the dose in the investigated dose range. The effects of pre-irradiation (shelf-life) and post-irradiation storage in dark and in indirect sunlight are also discussed. The results show that the dosimeters characteristics are stable within 1% at 25 C, 3 months after the irradiation.

High-dosage dosimetry programme of the IAEA

International Nuclear Information System (INIS)

Mehta, K.

1999-01-01

The high-dose dosimetry programme was initiated by the International Atomic Energy Agency in 1977. Like any other Agency programme, this one has various activities. These cover: research contracts and research agreements, co-ordinated research projects (CRP), training courses, and laboratory-based activities. The Agency's dose quality audit service (International Dose Assurance Service, IDAS), initiated in 1985, is one of the key elements of the programme. At earlier times, the technical part was operated through a laboratory in Germany. However, after purchasing the Bruker ESR spectrometer, the entire service has been operated from the Agency since 1992. This audit service has served well the needs of various institutes around the world involved with radiation processing. We have had two Co-ordinated Research Projects (the second one is in its last year) over the last several years. Both were/are aimed at standardization of dosimetry for radiation processing. Nine or ten participants of each CRP were about evenly distributed between the developed and developing Member States. In collaboration with the Food and Environmental Protection Section and the Industrial Applications and Chemistry Section, the Dosimetry and Medical Radiation Physics Section has participated in several training courses; these have been mainly regional courses. This collaboration has worked well since such courses combine specific radiation processing applications with the needs of good dosimetry and process control. Also, the Agency has organised several dose intercomparisons in recent time. The activities of the high-dose dosimetry programme since the last symposium (November 1990) are reviewed here. (author)

Polycarbonate-based benzo-δ-sultam films for high-dose dosimetry in radiation processing

Energy Technology Data Exchange (ETDEWEB)

Feizi, Shazad [University of Tehran, Tehran (India). School of Chemistry; Nuclear Science and Technology Research Institute, Tehran (Iran, Islamic Republic of). Radiation Application Research School; Ziaie, Farhood [Nuclear Science and Technology Research Institute, Tehran (Iran, Islamic Republic of). Radiation Application Research School; Ghandi, Mehdi [University of Tehran, Tehran (India). School of Chemistry

2015-05-01

In this work characteristics of the polycarbonate films with 20 μm in thickness containing different weight percentage of Benzo-δ-sultam were studied for use as a high dose dosimetry system in radiation processing facilities. The sensitivity of the dosimeters and the linearity of dose-response curves were investigated under {sup 60}Co γ-rays in a dose range of 0-100 kGy, and obtained results were compared with the commercial CTA and FWT film dosimeters. The results show that the absorbance at 348 nm depends linearly on the dose in the investigated dose range. The effects of pre-irradiation (shelf-life) and post-irradiation storage in dark and in indirect sunlight are also discussed. The results show that the dosimeters characteristics are stable within 1% at 25 C, 3 months after the irradiation.

Effects of dose fractionation on the response of alanine dosimetry

International Nuclear Information System (INIS)

Lundahl, Brad; Logar, John; Desrosiers, Marc; Puhl, James

2014-01-01

Alanine dosimetry is well established as a transfer standard and is becoming more prevalently used in routine dosimetry systems for radiation processing. Many routine measurement applications in radiation processing involve absorbed dose measurements resulting from fractioned exposures to ionizing radiation. Fractioning of absorbed dose is identified as an influence quantity (ISO/ASTM, 2013). This paper reports on study results of absorbed dose fractioning characteristics of alanine for gamma and high energy electron beam radiation sources. The results of this study indicate a radiation response difference due to absorbed dose fractioning in response can be observed after four fractionations for high-energy electron beams and no difference up to seven fractions for gamma rays using an ANOVA evaluation method. - Highlights: • Fractioning effects signaled in electron beam using an ANOVA at 6 equal increments. • Fractioning effects not signaled in gamma using an ANOVA up to 7 equal increments. • Insensitivity of alanine to dose fractioning indicates nominal impact on calibration

Radiation-damage studies, irradiations and high-dose dosimetry for LHC detectors

CERN Document Server

Coninckx, F; León-Florián, E; Leutz, H; Schönbacher, Helmut; Sonderegger, P; Tavlet, Marc; Sopko, B; Henschel, H; Schmidt, H U; Boden, A; Bräunig, D; Wulf, F; Cramariuc, R; Ilie, D; Fattibene, P; Onori, S; Miljanic, S; Paic, G; Razen, B; Razem, D; Rendic, D; CERN. Geneva. Detector Research and Development Committee

1991-01-01

The proposal is divided into a main project and special projects. The main project consists of a service similar to the one given in the past to accelerator construction projects at CERN (ISR,SPS,LEP) on high-dose dosimetry, material irradiations, irradiations tests, standardization of test procedures and data compilations. Large experience in this field and numerous radiation damage test data of insulating and structural materials are available. The special projects cover three topics which are of specific interest for LHC detector physicists and engineers at CERN and in other high energy physics institutes, namely: Radiation effects in scintillators; Selection of radiation hard optical fibres for data transmission; and Selection and testing of radiation hard electronic components.

Boron dose determination for BNCT using Fricke and EPR dosimetry

International Nuclear Information System (INIS)

Wielopolski, L.; Ciesielski, B.

1995-01-01

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

Shared dosimetry error in epidemiological dose-response analyses

International Nuclear Information System (INIS)

Stram, Daniel O.; Preston, Dale L.; Sokolnikov, Mikhail; Napier, Bruce; Kopecky, Kenneth J.; Boice, John; Beck, Harold; Till, John; Bouville, Andre; Zeeb, Hajo

2015-01-01

Radiation dose reconstruction systems for large-scale epidemiological studies are sophisticated both in providing estimates of dose and in representing dosimetry uncertainty. For example, a computer program was used by the Hanford Thyroid Disease Study to provide 100 realizations of possible dose to study participants. The variation in realizations reflected the range of possible dose for each cohort member consistent with the data on dose determinates in the cohort. Another example is the Mayak Worker Dosimetry System 2013 which estimates both external and internal exposures and provides multiple realizations of 'possible' dose history to workers given dose determinants. This paper takes up the problem of dealing with complex dosimetry systems that provide multiple realizations of dose in an epidemiologic analysis. In this paper we derive expected scores and the information matrix for a model used widely in radiation epidemiology, namely the linear excess relative risk (ERR) model that allows for a linear dose response (risk in relation to radiation) and distinguishes between modifiers of background rates and of the excess risk due to exposure. We show that treating the mean dose for each individual (calculated by averaging over the realizations) as if it was true dose (ignoring both shared and unshared dosimetry errors) gives asymptotically unbiased estimates (i.e. the score has expectation zero) and valid tests of the null hypothesis that the ERR slope β is zero. Although the score is unbiased the information matrix (and hence the standard errors of the estimate of β) is biased for β≠0 when ignoring errors in dose estimates, and we show how to adjust the information matrix to remove this bias, using the multiple realizations of dose. The use of these methods in the context of several studies including, the Mayak Worker Cohort, and the U.S. Atomic Veterans Study, is discussed

Dose Estimation from Daily and Weekly Dosimetry Data

International Nuclear Information System (INIS)

Ostrouchov, G.

2001-01-01

Statistical analyses of data from epidemiologic studies of workers exposed to radiation have been based on recorded annual radiation doses (yearly dose of record). It is usually assumed that the dose values are known exactly, although it is generally recognized that the data contain uncertainty due to measurement error and bias. In our previous work with weekly data, a probability distribution was used to describe an individual's dose during a specific period of time and statistical methods were developed for estimating it from weekly film dosimetry data. This study showed that the yearly dose of record systematically underestimates doses for Oak Ridge National Laboratory (ORNL) workers. This could result in biased estimates of dose-response coefficients and their standard errors. The results of this evaluation raise serious questions about the suitability of the yearly dose of record for direct use in low-dose studies of nuclear industry workers. Here, we extend our previous work to use full information in Pocket meter data and develop the Data Synthesis for Individual Dose Estimation (DSIDE) methodology. Although the DSIDE methodology in this study is developed in the context of daily and weekly data to produce a cumulative yearly dose estimate, in principle it is completely general and can be extended to other time period and measurement combinations. The new methodology takes into account the ''measurement error'' that is produced by the film and pocket-meter dosimetry systems, the biases introduced by policies that lead to recording left-censored doses as zeros, and other measurement and recording practices. The DSIDE method is applied to a sample of dose histories obtained from hard copy dosimetry records at ORNL for the years 1945 to 1955. First, the rigorous addition of daily pocket-meter information shows that the negative bias is generally more severe than was reported in our work based on weekly film data only, however, the amount of bias also varies

Dose Estimation from Daily and Weekly Dosimetry Data

Energy Technology Data Exchange (ETDEWEB)

Ostrouchov, G.

2001-11-16

Statistical analyses of data from epidemiologic studies of workers exposed to radiation have been based on recorded annual radiation doses (yearly dose of record). It is usually assumed that the dose values are known exactly, although it is generally recognized that the data contain uncertainty due to measurement error and bias. In our previous work with weekly data, a probability distribution was used to describe an individual's dose during a specific period of time and statistical methods were developed for estimating it from weekly film dosimetry data. This study showed that the yearly dose of record systematically underestimates doses for Oak Ridge National Laboratory (ORNL) workers. This could result in biased estimates of dose-response coefficients and their standard errors. The results of this evaluation raise serious questions about the suitability of the yearly dose of record for direct use in low-dose studies of nuclear industry workers. Here, we extend our previous work to use full information in Pocket meter data and develop the Data Synthesis for Individual Dose Estimation (DSIDE) methodology. Although the DSIDE methodology in this study is developed in the context of daily and weekly data to produce a cumulative yearly dose estimate, in principle it is completely general and can be extended to other time period and measurement combinations. The new methodology takes into account the ''measurement error'' that is produced by the film and pocket-meter dosimetry systems, the biases introduced by policies that lead to recording left-censored doses as zeros, and other measurement and recording practices. The DSIDE method is applied to a sample of dose histories obtained from hard copy dosimetry records at ORNL for the years 1945 to 1955. First, the rigorous addition of daily pocket-meter information shows that the negative bias is generally more severe than was reported in our work based on weekly film data only, however, the

Fabrication of a flexible polycarbonate/porphyrin film dosimeter for high dose dosimetry

Energy Technology Data Exchange (ETDEWEB)

Feizi, Shahzad [Nuclear Science and Technology Research Institute (NSTRI), Tehran (Iran, Islamic Republic of). Radiation Application Research School

2017-10-01

Dyed polycarbonate (PC) Radiochromic films with 20 μm thickness were prepared by casting of organic solution of PC containing 0.5 wt.% tetrakis (pentafluorophenyl) porphyrin (TPPF{sub 20}) on a glass petri dish. Characterization of the film as a routine dosimeter was studied. On subjecting PC/TPPF{sub 20} film dosimeter to gamma radiation, a gradual decrease in the color of films was observed. The sensitivity of these films and the linearity of dose-response curves were studied under {sup 60}Co γ-rays expose in dose range of 0-100 kGy. The results were compared with the commercial and non-commercial dosimeters. Experimental parameters including humidity, temperature and pre-irradiation (shelf-life) and post-irradiation storage in dark and in indirect sunlight were examined. The maximum absorbance of soret band of TPPF{sub 20} had a bathochromic shift and appeared at 414 nm which remained intact in the investigated dose range. The dyed films characteristics were found to be stable enough in media with high degrees of temperature and humidity. The results indicate that radiation induced decoloration of PC/TPPF{sub 20} films can be reliably used in high dose dosimetry.

Background dose subtraction in personnel dosimetry

International Nuclear Information System (INIS)

Picazo, T.; Llorca, N.; Alabau, J.

1997-01-01

In this paper it is proposed to consider the mode of the frequency distribution of the low dose dosemeters from each clinic that uses X rays as the background environmental dose that should be subtracted from the personnel dosimetry to evaluate the doses due to practice. The problems and advantages of this indirect method to estimate the environmental background dose are discussed. The results for 60 towns are presented. (author)

High energy dosimetry

International Nuclear Information System (INIS)

Ruhm, W.

2010-01-01

Full text: Currently, quantification of doses from high-energy radiation fields is a topical issue. This is so because high-energy neutrons play an important role for radiation exposure of air crew members and personnel outside the shielding of ion therapy facilities. In an effort to study air crew exposure from cosmic radiation in detail, two Bonner Sphere Spectrometers (BSSs) have recently been installed to measure secondary neutrons from cosmic radiation, one at the environmental research station 'Schneefernerhaus' at an altitude of 2650 m on the Zugspitze mountain, Germany, the other at the Koldewey station close to the North Pole on Spitsbergen. Based on the measured neutron fluence distributions and on fluence-to-dose conversion coefficients, mean ambient dose equivalent rate values of 75.0 ± 2.9 nSv/h and 8.7 ± 0.6 nSv/h were obtained for October 2008, respectively. Neutrons with energies above about 20 MeV contribute about 50% to dose, at 2650 m. Ambient dose equivalent rates measured by means of a standard rem counter and an extended rem counter at the Schneefernerhaus confirm this result. In order to study the response of state-of-the-art radiation instrumentation in such a high-energy radiation field, a benchmark exercise that included both measurements in and simulation of the stray neutron radiation field at the high-energy particle accelerator at GSI, Germany, were performed. This CONRAD (COordinated Network for RAdiation Dosimetry) project was funded by the European Commission, and the organizational framework was provided by the European Radiation Dosimetry Group, EURADOS. The Monte Carlo simulations of the radiation field and the experimental determination of the neutron spectra with various Bonner Sphere Spectrometers suggest the neutron fluence distributions to be very similar to those of secondary neutrons from cosmic radiation. The results of this intercomparison exercise in terms of ambient dose equivalent are also discussed

The spatial resolution in dosimetry with normoxic polymer-gels investigated with the dose modulation transfer approach

International Nuclear Information System (INIS)

Bayreder, Christian; Schoen, Robert; Wieland, M.; Georg, Dietmar; Moser, Ewald; Berg, Andreas

2008-01-01

The verification of dose distributions with high dose gradients as appearing in brachytherapy or stereotactic radiotherapy for example, calls for dosimetric methods with sufficiently high spatial resolution. Polymer gels in combination with a MR or optical scanner as a readout device have the potential of performing the verification of a three-dimensional dose distribution within a single measurement. The purpose of this work is to investigate the spatial resolution achievable in MR-based polymer gel dosimetry. The authors show that dosimetry on a very small spatial scale (voxel size: 94x94x1000 μm 3 ) can be performed with normoxic polymer gels using parameter selective T2 imaging. In order to prove the spatial resolution obtained we are relying on the dose-modulation transfer function (DMTF) concept based on very fine dose modulations at half periods of 200 μm. Very fine periodic dose modulations of a 60 Co photon field were achieved by means of an absorption grid made of tungsten-carbide, specifically designed for quality control. The dose modulation in the polymer gel is compared with that of film dosimetry in one plane via the DMTF concept for general access to the spatial resolution of a dose imaging system. Additionally Monte Carlo simulations were performed and used for the calculation of the DMTF of both, the polymer gel and film dosimetry. The results obtained by film dosimetry agree well with those of Monte Carlo simulations, whereas polymer gel dosimetry overestimates the amplitude value of the fine dose modulations. The authors discuss possible reasons. The in-plane resolution achieved in this work competes with the spatial resolution of standard clinical film-scanner systems

Research activities on dosimetry for high energy neutrons

Energy Technology Data Exchange (ETDEWEB)

Yamaguchi, Yasuhiro [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment

2003-03-01

The external dosimetry research group of JAERI has been calculating dose conversion coefficients for high-energy radiations using particle transport simulation codes. The group has also been developing radiation dose measurement techniques for high-energy neutrons in collaboration with some university groups. (author)

Monte Carlo Dosimetry of the 60Co BEBIG High Dose Rate for Brachytherapy.

Directory of Open Access Journals (Sweden)

Luciana Tourinho Campos

Full Text Available The use of high-dose-rate brachytherapy is currently a widespread practice worldwide. The most common isotope source is 192Ir, but 60Co is also becoming available for HDR. One of main advantages of 60Co compared to 192Ir is the economic and practical benefit because of its longer half-live, which is 5.27 years. Recently, Eckert & Ziegler BEBIG, Germany, introduced a new afterloading brachytherapy machine (MultiSource®; it has the option to use either the 60Co or 192Ir HDR source. The source for the Monte Carlo calculations is the new 60Co source (model Co0.A86, which is referred to as the new BEBIG 60Co HDR source and is a modified version of the 60Co source (model GK60M21, which is also from BEBIG.The purpose of this work is to obtain the dosimetry parameters in accordance with the AAPM TG-43U1 formalism with Monte Carlo calculations regarding the BEBIG 60Co high-dose-rate brachytherapy to investigate the required treatment-planning parameters. The geometric design and material details of the source was provided by the manufacturer and was used to define the Monte Carlo geometry. To validate the source geometry, a few dosimetry parameters had to be calculated according to the AAPM TG-43U1 formalism. The dosimetry studies included the calculation of the air kerma strength Sk, collision kerma in water along the transverse axis with an unbounded phantom, dose rate constant and radial dose function. The Monte Carlo code system that was used was EGSnrc with a new cavity code, which is a part of EGS++ that allows calculating the radial dose function around the source. The spectrum to simulate 60Co was composed of two photon energies, 1.17 and 1.33 MeV. Only the gamma part of the spectrum was used; the contribution of the electrons to the dose is negligible because of the full absorption by the stainless-steel wall around the metallic 60Co. The XCOM photon cross-section library was used in subsequent simulations, and the photoelectric effect, pair

Biological dosimetry in cases gives occupational high exposition to ionizing radiations

International Nuclear Information System (INIS)

Ramalho, Adriana T.; Costa, Maria Lucia P.; Oliveira, Monica S.; Silva, Francisco Cesar A.

1998-01-01

From 1983 the cytogenetics dosimetry method it has been used as routine in the IRD laboratory in the period 1983 at 1997 but a high exposition occupational case the physical dosimeters happened in Brazil they were investigated through the cytogenetics dosimetry technique. This technique is employ when the dosimetry personal marks a high dose to 100 mSv (0,1 Gy) that is the cut-off minimum detected in the dosimetry cytogenetics

Design and implementation of a film dosimetry audit tool for comparison of planned and delivered dose distributions in high dose rate (HDR) brachytherapy

Science.gov (United States)

Palmer, Antony L.; Lee, Chris; Ratcliffe, Ailsa J.; Bradley, David; Nisbet, Andrew

2013-10-01

A novel phantom is presented for ‘full system’ dosimetric audit comparing planned and delivered dose distributions in HDR gynaecological brachytherapy, using clinical treatment applicators. The brachytherapy applicator dosimetry test object consists of a near full-scatter water tank with applicator and film supports constructed of Solid Water, accommodating any typical cervix applicator. Film dosimeters are precisely held in four orthogonal planes bisecting the intrauterine tube, sampling dose distributions in the high risk clinical target volume, points A and B, bladder, rectum and sigmoid. The applicator position is fixed prior to CT scanning and through treatment planning and irradiation. The CT data is acquired with the applicator in a near clinical orientation to include applicator reconstruction in the system test. Gamma analysis is used to compare treatment planning system exported RTDose grid with measured multi-channel film dose maps. Results from two pilot audits are presented, using Ir-192 and Co-60 HDR sources, with a mean gamma passing rate of 98.6% using criteria of 3% local normalization and 3 mm distance to agreement (DTA). The mean DTA between prescribed dose and measured film dose at point A was 1.2 mm. The phantom was funded by IPEM and will be used for a UK national brachytherapy dosimetry audit.

Design and implementation of a film dosimetry audit tool for comparison of planned and delivered dose distributions in high dose rate (HDR) brachytherapy

International Nuclear Information System (INIS)

Palmer, Antony L; Bradley, David; Nisbet, Andrew; Lee, Chris; Ratcliffe, Ailsa J

2013-01-01

A novel phantom is presented for ‘full system’ dosimetric audit comparing planned and delivered dose distributions in HDR gynaecological brachytherapy, using clinical treatment applicators. The brachytherapy applicator dosimetry test object consists of a near full-scatter water tank with applicator and film supports constructed of Solid Water, accommodating any typical cervix applicator. Film dosimeters are precisely held in four orthogonal planes bisecting the intrauterine tube, sampling dose distributions in the high risk clinical target volume, points A and B, bladder, rectum and sigmoid. The applicator position is fixed prior to CT scanning and through treatment planning and irradiation. The CT data is acquired with the applicator in a near clinical orientation to include applicator reconstruction in the system test. Gamma analysis is used to compare treatment planning system exported RTDose grid with measured multi-channel film dose maps. Results from two pilot audits are presented, using Ir-192 and Co-60 HDR sources, with a mean gamma passing rate of 98.6% using criteria of 3% local normalization and 3 mm distance to agreement (DTA). The mean DTA between prescribed dose and measured film dose at point A was 1.2 mm. The phantom was funded by IPEM and will be used for a UK national brachytherapy dosimetry audit. (paper)

Effective dose to staff from interventional procedures: Estimations from single and double dosimetry

International Nuclear Information System (INIS)

Kuipers, G.; Velders, X. L.

2009-01-01

The exposure of 11 physicians performing interventional procedures was measured by means of two personal dosemeters. One personal dosemeter was worn outside the lead apron and an additional under the lead apron. The study was set up in order to determine the added value of a dosemeter worn under the lead apron. With the doses measured, the effective doses of the physicians were estimated using an algorithm for single dosimetry and two algorithms for double dosimetry. The effective doses calculated with the single dosimetry algorithm ranged from 0.11 to 0.85 mSv in 4 weeks. With the double dosimetry algorithms, the effective doses ranged from 0.02 mSv to 0.47 mSv. The statistical analysis revealed no significant differences in the accuracy of the effective doses calculated with single or double dosimetry algorithms. It was concluded that the effective dose cannot be considered a more accurate estimate when two dosemeters are used instead of one. (authors)

The use of polymer gel dosimetry to measure dose distribution around metallic implants

International Nuclear Information System (INIS)

Nagahata, Tomomasa; Yamaguchi, Hajime; Monzen, Hajime; Nishimura, Yasumasa

2014-01-01

A semi-solid polymer dosimetry system using agar was developed to measure the dose distribution close to metallic implants. Dosimetry of heterogeneous fields where electron density markedly varies is often problematic. This prompted us to develop a polymer gel dosimetry technique using agar to measure the dose distribution near substance boundaries. Varying the concentration of an oxygen scavenger (tetra-hydroxymethyl phosphonium chloride) showed the absorbed dose and transverse relaxation rate of the magnetic resonance signal to be linear between 3 and 12 Gy. Although a change in the dosimeter due to oxidization was observed in room air after 24 hours, no such effects were observed in the first 4 hours. The dose distribution around the metal implants was measured using agar dosimetry. The metals tested were a lead rod, a titanium hip joint, and a metallic stent. A maximum 30% dose increase was observed near the lead rod, but only a 3% increase in the absorbed dose was noted near the surface of the titanium hip joint and metallic stent. Semi-solid polymer dosimetry using agar thus appears to be a useful method for dosimetry around metallic substances. (author)

[The use of polymer gel dosimetry to measure dose distribution around metallic implants].

Science.gov (United States)

Nagahata, Tomomasa; Yamaguchi, Hajime; Monzen, Hajime; Nishimura, Yasumasa

2014-10-01

A semi-solid polymer dosimetry system using agar was developed to measure the dose distribution close to metallic implants. Dosimetry of heterogeneous fields where electron density markedly varies is often problematic. This prompted us to develop a polymer gel dosimetry technique using agar to measure the dose distribution near substance boundaries. Varying the concentration of an oxygen scavenger (tetra-hydroxymethyl phosphonium chloride) showed the absorbed dose and transverse relaxation rate of the magnetic resonance signal to be linear between 3 and 12 Gy. Although a change in the dosimeter due to oxidization was observed in room air after 24 hours, no such effects were observed in the first 4 hours. The dose distribution around the metal implants was measured using agar dosimetry. The metals tested were a lead rod, a titanium hip joint, and a metallic stent. A maximum 30% dose increase was observed near the lead rod, but only a 3% increase in the absorbed dose was noted near the surface of the titanium hip joint and metallic stent. Semi-solid polymer dosimetry using agar thus appears to be a useful method for dosimetry around metallic substances.

Conversion from tooth enamel dose to organ doses for electron spin resonance dosimetry

International Nuclear Information System (INIS)

Takahashi, Fumiaki; Yamaguchi, Yasuhiro; Saito, Kimiaki; Hamada, Tatsuji

2002-01-01

Conversion from tooth enamel dose to organ doses was analyzed to establish a method of retrospective individual dose assessment against external photon exposure by electron spin resonance (ESR) dosimetry. Dose to tooth enamel was obtained by Monte Carlo calculations using a modified MIRD-type phantom with a teeth part. The calculated tooth enamel doses were verified by measurements with thermo-luminescence dosimeters inserted in a physical head phantom. Energy and angular dependences of tooth enamel dose were compared with those of other organ doses. Additional Monte Carlo calculations were performed to study the effect of human model on the tooth enamel dose with a voxel-type phantom, which was based on computed tomography images of the physical phantom. The data derived with the modified MIRD-type phantom were applied to convert from tooth enamel dose to organ doses against external photon exposure in a hypothesized field, where scattered radiation was taken into account. The results indicated that energy distribution of photons incident to a human body is required to evaluate precisely an individual dose based on ESR dosimetry for teeth. (author)

Dosimetry investigation of MOSFET for clinical IMRT dose verification.

Science.gov (United States)

Deshpande, Sudesh; Kumar, Rajesh; Ghadi, Yogesh; Neharu, R M; Kannan, V

2013-06-01

In IMRT, patient-specific dose verification is followed regularly at each centre. Simple and efficient dosimetry techniques play a very important role in routine clinical dosimetry QA. The MOSFET dosimeter offers several advantages over the conventional dosimeters such as its small detector size, immediate readout, immediate reuse, multiple point dose measurements. To use the MOSFET as routine clinical dosimetry system for pre-treatment dose verification in IMRT, a comprehensive set of experiments has been conducted, to investigate its linearity, reproducibility, dose rate effect and angular dependence for 6 MV x-ray beam. The MOSFETs shows a linear response with linearity coefficient of 0.992 for a dose range of 35 cGy to 427 cGy. The reproducibility of the MOSFET was measured by irradiating the MOSFET for ten consecutive irradiations in the dose range of 35 cGy to 427 cGy. The measured reproducibility of MOSFET was found to be within 4% up to 70 cGy and within 1.4% above 70 cGy. The dose rate effect on the MOSFET was investigated in the dose rate range 100 MU/min to 600 MU/min. The response of the MOSFET varies from -1.7% to 2.1%. The angular responses of the MOSFETs were measured at 10 degrees intervals from 90 to 270 degrees in an anticlockwise direction and normalized at gantry angle zero and it was found to be in the range of 0.98 ± 0.014 to 1.01 ± 0.014. The MOSFETs were calibrated in a phantom which was later used for IMRT verification. The measured calibration coefficients were found to be 1 mV/cGy and 2.995 mV/cGy in standard and high sensitivity mode respectively. The MOSFETs were used for pre-treatment dose verification in IMRT. Nine dosimeters were used for each patient to measure the dose in different plane. The average variation between calculated and measured dose at any location was within 3%. Dose verification using MOSFET and IMRT phantom was found to quick and efficient and well suited for a busy radiotherapy

Alanine EPR dosimetry of therapeutic irradiators

International Nuclear Information System (INIS)

Bugay, O.; Bartchuk, V.; Kolesnik, S.; Mazin, M.; Gaponenko, H.

1999-01-01

The high-dose alanine EPR dosimetry is a very precise method in the dose range 1-100 kGy. The system is used generally as the standard high-dose transfer dosimetry in many laboratories. This is comparatively expensive technique so it is important to use it as a more universal dosimetry system also in the middle and low dose ranges. The problems of the middle-dose alanine dosimetry are discussed and the solution of several problems is proposed. The alanine EPR dosimetry has been applied to the dose measurements of medical irradiators in the Kiev City Oncology Center. (author)

In vivo dosimetry: measurement of entrance and exit dose using MOSFET dosimeter

International Nuclear Information System (INIS)

Gopiraj, A.; Billimagga, Ramesh S.; Rekha, M.; Ramasubramaniam, V.

2007-01-01

Patient dose verification is an essential part of a Quality Assurance (QA) program in a Radiotherapy Department. As the transition is made from the conventional two-dimensional (2D) to three-dimensional (3D) conformal and intensity modulated therapy, it is recommended that new treatment techniques be checked systematically to guarantee accurate dose delivery by means of a comprehensive in vivo dosimetry program (i.e. real-time dosimetry during patient treatment). The authors conducted a study to assess the clinical utility of in vivo dosimetry in the Dept. of Radiation Oncology using MOSFET dosimetry system

Standardization of high-dose measurement of electron and gamma ray absorbed doses and dose rates

International Nuclear Information System (INIS)

McLaughlin, W.L.

1985-01-01

Intense electron beams and gamma radiation fields are used for sterilizing medical devices, treating municipal wastes, processing industrial goods, controlling parasites and pathogens, and extending the shelf-life of foods. Quality control of such radiation processes depends largely on maintaining measurement quality assurance through sound dosimetry procedures in the research leading to each process, in the commissioning of that process, and in the routine dose monitoring practices. This affords documentation as to whether satisfactory dose uniformity is maintained throughout the product and throughout the process. Therefore, dosimetry at high doses and dose rates must in many radiation processes be standardized carefully, so that 'dosimetry release' of a product is verified. This standardization is initiated through preliminary dosimetry intercomparison studies such as those sponsored recently by the IAEA. This is followed by establishing periodic exercises in traceability to national or international standards of absorbed dose and dose rate. Traceability is achieved by careful selection of dosimetry methods and proven reference dosimeters capable of giving sufficiently accurate and precise 'transfer' dose assessments: (1) they must be calibrated or have well-established radiation-yield indices; (2) their radiation response characteristics must be reproducible and cover the dose range of interest; (3) they must withstand the rigours of back-and-forth mailing between a central standardizing laboratory and radiation processing facilities, without excessive errors arising due to instabilities, dosimeter batch non-uniformities, and environmental and handling stresses. (author)

IAEA/WHO TLD postal dose audit service and high precision measurements for radiotherapy level dosimetry

International Nuclear Information System (INIS)

Izewska, J.; Bera, P.; Vatnitsky, S.

2002-01-01

Since 1969 the International Atomic Energy Agency, together with the World Health Organization, has performed postal TLD audits to verify calibration of radiotherapy beams in developing countries. The TLD programme also monitors activities of Secondary Standard Dosimetry Laboratories (SSDLs). The programme has checked approximately 4000 clinical beams in over 1100 hospitals, and in many instances significant errors have been detected in the beam calibration. Subsequent follow-up actions help to resolve the discrepancies, thus preventing further mistreatment of patients. The audits for SSDLs check the implementation of the dosimetry protocol in order to assure proper dissemination of dosimetry standards to the end-users. The TLD audit results for SSDLs show good consistency in the basic dosimetry worldwide. New TLD procedures and equipment have recently been introduced by the IAEA that include a modified TLD calibration methodology and computerised tools for automation of dose calculation from TLD readings. (author)

Absorbed dose determination in external beam radiotherapy. An international code of practice for dosimetry based on standards of absorbed dose to water

International Nuclear Information System (INIS)

2000-01-01

The International Atomic Energy Agency published in 1987 an International Code of Practice entitled 'Absorbed Dose Determination in Photon and Electron Beams' (IAEA Technical Reports Series No. 277 (TRS-277)), recommending procedures to obtain the absorbed dose in water from measurements made with an ionization chamber in external beam radiotherapy. A second edition of TRS-277 was published in 1997 updating the dosimetry of photon beams, mainly kilovoltage X rays. Another International Code of Practice for radiotherapy dosimetry entitled 'The Use of Plane-Parallel Ionization Chambers in High Energy Electron and Photon Beams' (IAEA Technical Reports Series No. 381 (TRS-381)) was published in 1997 to further update TRS-277 and complement it with respect to the area of parallel-plate ionization chambers. Both codes have proven extremely valuable for users involved in the dosimetry of the radiation beams used in radiotherapy. In TRS-277 the calibration of the ionization chambers was based on primary standards of air kerma; this procedure was also used in TRS-381, but the new trend of calibrating ionization chambers directly in a water phantom in terms of absorbed dose to water was introduced. The development of primary standards of absorbed dose to water for high energy photon and electron beams, and improvements in radiation dosimetry concepts, offer the possibility of reducing the uncertainty in the dosimetry of radiotherapy beams. The dosimetry of kilovoltage X rays, as well as that of proton and heavy ion beams, interest in which has grown considerably in recent years, can also be based on these standards. Thus a coherent dosimetry system based on standards of absorbed dose to water is possible for practically all radiotherapy beams. Many Primary Standard Dosimetry Laboratories (PSDLs) already provide calibrations in terms of absorbed dose to water at the radiation quality of 60 Co gamma rays. Some laboratories have extended calibrations to high energy photon and

Radiation-Induced Color Centers in LiF for Dosimetry at High Absorbed Dose Rates

DEFF Research Database (Denmark)

McLaughlin, W. L.; Miller, Arne; Ellis, S. C.

1980-01-01

Color centers formed by irradiation of optically clear crystals of pure LiF may be analyzed spectrophotometrically for dosimetry in the absorbed dose range from 102 to 107 Gy. Routine monitoring of intense electron beams is an important application. Both 6LiF and 7LiF forms are commercially...... available, and when used with filters as albedo dosimeters in pairs, they provide discrimination of neutron and gamma-ray doses....

Development a high-resolution radiation dosimetry system based on Fricke solutions

Energy Technology Data Exchange (ETDEWEB)

Vedelago, J. [Laboratorio de Investigaciones e Instrumentacion en Fisica Aplicada a la Medicina e Imagenes por Rayos X, Laboratorio 448 FaMAF - UNC, Ciudad Universitaria, 5000 Cordoba (Argentina); Mattea, F. [Universidad Nacional de Cordoba, Facultad de Ciencias Quimicas, Departamento de Quimica Organica, Ciudad Universitaria, 5000 Cordoba (Argentina); Valente, M., E-mail: josevedelago@gmail.com [Instituto de Fisica E. Gaviola, Oficina 102 FaMAF - UNC, Ciudad Universitaria, 5000 Cordoba (Argentina)

2014-08-15

Due to the growing complexity of modern medical procedures involving the use of ionizing radiation, dosimetry by non-conventional techniques is one of the research areas in the field of greatest interest nowadays. Tissue-equivalent high-resolution dosimetry systems capable of attaining continuous dose mapping are required. In this scenario, Fricke gel dosimetry is a very promising option for in-phantom dose measurements in complex radiation techniques. Implementation of this technique requires dedicated instruments capable of measuring and performing the immediate in situ analysis of the acquired data at the radiation facility. The versatility of Fricke gel dosimetry in different applications depending on the chemical and isotopic composition of the dosimeter extends its application to different high performance conventional and non-conventional radiation procedures involving diverse types of radiation treatments and also radiation diagnosis procedures. This work presents an integral dosimetry system, based on Fricke gel solutions and their analysis by optical techniques, aiming for an increase in the precision on dose determinations. The chemical synthesis and dosimeter preparation were accomplished at LIIFAMIRx facilities, following the procedures and protocols described in previous works. Additionally, specific instrumentation for optical sample analysis was completely designed and constructed at LIIFAMIRx facilities. The main outcome of this work was the development of a methodology that improves the integral dose determination performance by the pre-irradiation of Fricke gel dosimeters. (author)

Development a high-resolution radiation dosimetry system based on Fricke solutions

International Nuclear Information System (INIS)

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

2014-08-01

Due to the growing complexity of modern medical procedures involving the use of ionizing radiation, dosimetry by non-conventional techniques is one of the research areas in the field of greatest interest nowadays. Tissue-equivalent high-resolution dosimetry systems capable of attaining continuous dose mapping are required. In this scenario, Fricke gel dosimetry is a very promising option for in-phantom dose measurements in complex radiation techniques. Implementation of this technique requires dedicated instruments capable of measuring and performing the immediate in situ analysis of the acquired data at the radiation facility. The versatility of Fricke gel dosimetry in different applications depending on the chemical and isotopic composition of the dosimeter extends its application to different high performance conventional and non-conventional radiation procedures involving diverse types of radiation treatments and also radiation diagnosis procedures. This work presents an integral dosimetry system, based on Fricke gel solutions and their analysis by optical techniques, aiming for an increase in the precision on dose determinations. The chemical synthesis and dosimeter preparation were accomplished at LIIFAMIRx facilities, following the procedures and protocols described in previous works. Additionally, specific instrumentation for optical sample analysis was completely designed and constructed at LIIFAMIRx facilities. The main outcome of this work was the development of a methodology that improves the integral dose determination performance by the pre-irradiation of Fricke gel dosimeters. (author)

Characterization of silicates and calcium carbonates applied to high-dose dosimetry

International Nuclear Information System (INIS)

Vila, Gustavo Barreto

2012-01-01

The predominant isomorphous form in the biominerals studied in this work (oyster shell, coral, mother of pearl and shell) was aragonite. The appearance of the calcite phase occurred at 500 deg C at a heating rate of 10 deg C /s for all samples except for the coral sample, which was 400 deg C, independent of the heating rate. The most abundant element in the biominerals samples was Ca in the CaO form, and in the silicates (tremolite, diopside and rhodonite) Si in the SiO form. The most common trace element observed in the biominerals samples was Fe. The analyses of electron paramagnetic resonance showed lines of Mn 2+ in the coral and mother-of-pearl samples before irradiation. In the case of the irradiated samples, the defects found were CO 2 - , CO 3 3- , CO 3 - and SO 2 - , in the g range between 2.0010 and 2.0062. In the analyses by optical absorption of biominerals, transitions due to the presence of Mn in the samples were found. A thermoluminescent (TL) peak at approximately 140 deg C was found for the biominerals and at 180 deg C for silicates, which intensity depends directly on the dose. For samples exposed to different types of radiation, the TL peak occurred at lower temperatures. From the dose-response curves obtained for these materials, it was possible to determine a linear range for which their application in high dose dosimetry becomes possible. Taking into account the radiation type, among biominerals and silicates, the lowest detectable dose (40mGy) to gamma radiation was achieved for oyster shell samples using the measuring technique of optically stimulated luminescence (OSL). Using beta radiation, for diopside and tremolite samples the lowest detectable dose of 60mGy was obtained. For all samples, using the TL, OSL and thermally stimulated exoelectron emission (TSEE) techniques in alpha, beta and gamma radiation beans a good response reproducibility was obtained. Therefore, the samples characterized in this work are suitable to be used as high

High Energy Electron Dosimetry by Alanine/ESR Spectroscopy

International Nuclear Information System (INIS)

Chu, Sung Sil

1989-01-01

Dosimetry based on electron spin resonance(ESR) analysis of radiation induced free radicals in amino acids is relevant to biological dosimetry applications. Alanine detectors are without walls and are tissue equivalent. Therefore, alanine ESR dosimetry looks promising for use in the therapy level. The dose range of the alanine/ESR dosimetry system can be extended down to l Gy. In a water phantom the absorbed dose of electrons generated by a medical linear accelerator of different initial energies (6-21 MeV) and therapeutic dose levels(1-60 Gy) was measured. Furthermore, depth dose measurements carried out with alanine dosimeters were compared with ionization chamber measurements. As the results, the measured absorbed doses for shallow depth of initial electron energies above 15 MeV were higher by 2-5% than those calculated by nominal energy CE factors. This seems to be caused by low energy scattered beams generated from the scattering foil and electron cones of beam projecting device in medical linear accelerator

Skin dosimetry - radiological protection aspects of skin dosimetry

International Nuclear Information System (INIS)

Dennis, J.A.

1991-01-01

Following a Workshop in Skin Dosimetry, a summary of the radiological protection aspects is given. Aspects discussed include routine skin monitoring and dose limits, the need for careful skin dosimetry in high accidental exposures, techniques for assessing skin dose at all relevant depths and the specification of dose quantities to be measured by personal dosemeters and the appropriate methods to be used in their calibration. (UK)

Revue of some dosimetry and dose assessment European projects

International Nuclear Information System (INIS)

Bolognese-Milsztajn, T.; Frank, D.; Lacoste, V.; Pihet, P.

2006-01-01

Full text of publication follows: Within the 5. Framework Programme of the European Commission several project dealing with dosimetry and dose assessment for internal and external exposure have been supported. A revue of the results of some of them is presented in this paper. The EURADOS network which involved 50 dosimetry institutes in EUROPE has coordinated the project DOSIMETRY NETWORK: the main results achieved within this action are the following: - The release on the World Wide Web of the EURADOS Database of Dosimetry Research Facilities; - The realisation of the report 'Harmonization of Individual Monitoring (IM) in Europe'; - The continuation of the intercomparisons programme of environmental radiation monitoring systems; - The realisation of the report Cosmic radiation exposure of aircraft crew. The EVIDOS project aimed at evaluating state of the art dosimetry techniques in representative workplaces of the nuclear industry with complex mixed neutron-photon radiation fields. This paper summarises the main findings from a practical point of view. Conclusions and recommendations will be given concerning characterisation of radiation fields, methods to derive radiation protection quantities and dosimeters results. The IDEA project aimed to improve the assessment of incorporated radionuclides through developments of advanced in-vivo and bioassay monitoring techniques and making use of such enhancements for improvements in routine monitoring. The primary goal was to categorize those new developments regarding their potential and eligibility for the routine monitoring community. The costs of monitoring for internal exposures in the workplace are usually significantly greater than the equivalent costs for external exposures. There is therefore a need to ensure that resources are employed with maximum effectiveness. The EC-funded OMINEX (Optimisation of Monitoring for Internal Exposure) project has developed methods for optimising the design and implementation of

Why is a high accuracy needed in dosimetry

International Nuclear Information System (INIS)

Lanzl, L.H.

1976-01-01

Dose and exposure intercomparisons on a national or international basis have become an important component of quality assurance in the practice of good radiotherapy. A high degree of accuracy of γ and x radiation dosimetry is essential in our international society, where medical information is so readily exchanged and used. The value of accurate dosimetry lies mainly in the avoidance of complications in normal tissue and an optimal degree of tumor control

Polymer gel dosimetry for synchrotron stereotactic radiotherapy and iodine dose-enhancement measurements

International Nuclear Information System (INIS)

Boudou, C; Tropres, I; Rousseau, J; Lamalle, L; Adam, J F; Esteve, F; Elleaume, H

2007-01-01

Synchrotron stereotactic radiotherapy (SSR) is a radiotherapy technique that makes use of the interactions of monochromatic low energy x-rays with high atomic number (Z) elements. An important dose-enhancement can be obtained if the target volume has been loaded with a sufficient amount of a high-Z element, such as iodine. In this study, we compare experimental dose measurements, obtained with normoxic polymer gel (nPAG), with Monte Carlo computations. Gels were irradiated within an anthropomorphic head phantom and were read out by magnetic resonance imaging. The dose-enhancement due to the presence of iodine in the gel (iodine concentration: 5 and 10 mg ml -1 ) was measured at two radiation energies (35 and 80 keV) and was compared to the calculated factors. nPAG dosimetry was shown to be efficient for measuring the sharp dose gradients produced by SSR. The agreement between 3D gel dosimetry and calculated dose distributions was found to be within 4% of the dose difference criterion and a distance to agreement of 2.1 mm for 80% of the voxels. Polymer gel doped with iodine exhibited higher sensitivity, in good agreement with the calculated iodine-dose enhancement. We demonstrate in this preliminary study that iodine-doped nPAG could be used for measuring in situ dose distributions for iodine-enhanced SSR treatment

Dosimetric properties of bio minerals applied to high-dose dosimetry using the TSEE technique

International Nuclear Information System (INIS)

Vila, G. B.; Caldas, L. V. E.

2014-08-01

The study of the dosimetric properties such as reproducibility, the residual signal, lower detection dose, dose-response curve and fading of the thermally stimulated emission exo electronic (TSEE) signal of Brazilian bio minerals has shown that these materials present a potential use as radiation dosimeters. The reproducibility within ± 10% for oyster shell, mother-of-pearl and coral reef samples showed that the signal dispersion is small when compared with the mean value of the measurements. The study showed that the residual signal can be eliminated with a thermal treatment at 300 grades C/1 h. The lower detection dose of 9.8 Gy determined for the oyster shell samples when exposed to beta radiation and 1.6 Gy for oyster shell and mother-of-pearl samples when exposed to gamma radiation can be considered good, taking into account the high doses of this study. The materials presented linearity at the dose response curves in some ranges, but the lack of linearity in other cases presents no problem since a good mathematical description is possible. The fading study showed that the loss of TSEE signal can be minimized if the samples are protected from interferences such as light, heat and humidity. Taking into account the useful linearity range as the main dosimetric characteristic, the tiger shell and oyster shell samples are the most suitable for high-dose dosimetry using the TSEE technique. (Author)

Dosimetric properties of bio minerals applied to high-dose dosimetry using the TSEE technique

Energy Technology Data Exchange (ETDEWEB)

Vila, G. B.; Caldas, L. V. E., E-mail: gbvila@ipen.br [Instituto de Pesquisas Energeticas e Nucleares / CNEN, Av. Lineu Prestes 2242, Cidade Universitaria, 05508-000 Sao Paulo (Brazil)

2014-08-15

The study of the dosimetric properties such as reproducibility, the residual signal, lower detection dose, dose-response curve and fading of the thermally stimulated emission exo electronic (TSEE) signal of Brazilian bio minerals has shown that these materials present a potential use as radiation dosimeters. The reproducibility within ± 10% for oyster shell, mother-of-pearl and coral reef samples showed that the signal dispersion is small when compared with the mean value of the measurements. The study showed that the residual signal can be eliminated with a thermal treatment at 300 grades C/1 h. The lower detection dose of 9.8 Gy determined for the oyster shell samples when exposed to beta radiation and 1.6 Gy for oyster shell and mother-of-pearl samples when exposed to gamma radiation can be considered good, taking into account the high doses of this study. The materials presented linearity at the dose response curves in some ranges, but the lack of linearity in other cases presents no problem since a good mathematical description is possible. The fading study showed that the loss of TSEE signal can be minimized if the samples are protected from interferences such as light, heat and humidity. Taking into account the useful linearity range as the main dosimetric characteristic, the tiger shell and oyster shell samples are the most suitable for high-dose dosimetry using the TSEE technique. (Author)

Lyoluminescence dosimetry of the radiation in industrial doses

International Nuclear Information System (INIS)

Vigna Filho, E. del.

1984-01-01

The γ-rays lyoluminescence (LL) dosimetry study is presented. The basic principles involved, both in the method and radiation dosimetry, the equivalence between water and lyoluminescent materials, apparatus, irradiation technique and calibration method are discussed. The LL response dependence with environmental conditions are presented. These were temperature, humidity, storage time and the dependence on dissolved mass. A pre-reading thermal treatment was developed to overcome previous difficulties. The developed technique was applied to dose intercomparisons. (M.A.C.) [pt

IAEA advisory group meeting on dosimetry for high doses employed in industrial radiation processing, Vienna, 17-21 November 1980

International Nuclear Information System (INIS)

Chadwick, K.H.

1981-01-01

In 1977 the IAEA established a programme on High-Dose Standardization and Intercomparison with the aim of developing a world-wide service for dosimetry assurance in Industrial and Research Radiation Processing Facilities. The complete proceedings of the first Advisory Group meeting held within this programme have recently been published in the IAEA Technical Reports Series (No. 205) under the title ''High-Dose Measurement in Industrial Radiation Processing''. This report of the second Advisory Group meeting provides a brief review of the state of the programme at the present time. (The full proceedings of the meeting will not be published)

On the feasibility of comprehensive high-resolution 3D remote dosimetry

International Nuclear Information System (INIS)

Juang, Titania; Grant, Ryan; Adamovics, John; Ibbott, Geoffrey; Oldham, Mark

2014-01-01

Purpose: This study investigates the feasibility of remote high-resolution 3D dosimetry with the PRESAGE®/Optical-CT system. In remote dosimetry, dosimeters are shipped out from a central base institution to a remote institution for irradiation, then shipped back to the base institution for subsequent readout and analysis. Methods: Two nominally identical optical-CT scanners for 3D dosimetry were constructed and placed at the base (Duke University) and remote (Radiological Physics Center) institutions. Two formulations of PRESAGE® (SS1, SS2) radiochromic dosimeters were investigated. Higher sensitivity was expected in SS1, which had higher initiator content (0.25% bromotrichloromethane), while greater temporal stability was expected in SS2. Four unirradiated PRESAGE® dosimeters (two per formulation, cylindrical dimensions 11 cm diameter, 8.5–9.5 cm length) were imaged at the base institution, then shipped to the remote institution for planning and irradiation. Each dosimeter was irradiated with the same simple treatment plan: an isocentric 3-field “cross” arrangement of 4 × 4 cm open 6 MV beams configured as parallel opposed laterals with an anterior beam. This simple plan was amenable to accurate and repeatable setup, as well as accurate dose modeling by a commissioned treatment planning system (Pinnacle). After irradiation and subsequent (within 1 h) optical-CT readout at the remote institution, the dosimeters were shipped back to the base institution for remote dosimetry readout 3 days postirradiation. Measured on-site and remote relative 3D dose distributions were registered to the Pinnacle dose calculation, which served as the reference distribution for 3D gamma calculations with passing criteria of 5%/2 mm, 3%/3 mm, and 3%/2 mm with a 10% dose threshold. Gamma passing rates, dose profiles, and color-maps were all used to assess and compare the performance of both PRESAGE® formulations for remote dosimetry. Results: The best agreements between the

Cytogenetic biological dosimetry. Dose estimative in accidental exposure

International Nuclear Information System (INIS)

Santos, O.R. dos; Campos, I.M.A. de.

1988-01-01

The methodology of cytogenetic biological dosimetry is studied. The application in estimation of dose in five cases of accidental exposure is reported. An hematological study and culture of lymphocytes is presented. (M.A.C.) [pt

An absorbed dose calorimeter for IMRT dosimetry

International Nuclear Information System (INIS)

Duane, S.; Aldehaybes, M.; Bailey, M.; Lee, N.D.; Thomas, C.G.; Palmans, H.

2012-01-01

A new calorimeter for dosimetry in small and complex fields has been built. The device is intended for the direct determination of absorbed dose to water in moderately small fields and in composite fields such as IMRT treatments, and as a transfer instrument calibrated against existing absorbed dose standards in conventional reference conditions. The geometry, materials and mode of operation have been chosen to minimize detector perturbations when used in a water phantom, to give a reasonably isotropic response and to minimize the effects of heat transfer when the calorimeter is used in non-reference conditions in a water phantom. The size of the core is meant to meet the needs of measurement in IMRT treatments and is comparable to the size of the air cavity in a type NE2611 ionization chamber. The calorimeter may also be used for small field dosimetry. Initial measurements in reference conditions and in an IMRT head and neck plan, collapsed to gantry angle zero, have been made to estimate the thermal characteristics of the device, and to assess its performance in use. The standard deviation (estimated repeatability) of the reference absorbed dose measurements was 0.02 Gy (0.6%). (authors)

PTTL Dose Re-estimation Applied to Quality Control in TLD-100 Based Personal Dosimetry

International Nuclear Information System (INIS)

Muniz, J.L.; Correcher, V.; Delgado, A.

1999-01-01

A new method for quality control of dose performance in Personal Dosimetry using TLD-100 is presented. This method consists of the application of dose reassessment techniques based on phototransferred thermoluminescence (PTTL). Reassessment is achieved through a second TL readout of the dosemeters worn by the controlled workers, after a reproducible UV exposure. Recent refinements in the PTTL technique developed in our laboratory allow reassessing doses as low as 0.2 mSv, thus extending the reassessment capability to the entire dose range that must be monitored in personal dosimetry. After a one month exposure, even purely environmental doses can be reassessed. This method can be applied for either re-estimation of single doses or of the total dose accumulated after a number of exposures and dose measurements. Several tests to reconfirm low doses in normal working conditions for personal dosimetry have been performed. Each test consisted of several cycles of exposure and TL evaluations and a final PTTL re-estimation of the total accumulated dose in those cycles. The results obtained always showed very good agreement between the sum of the partial doses and the total reassessed dose. The simplicity of the method and the possibility of re-evaluating the doses assessed to the workers employing their own dosemeters are advantageous features to be considered in designing systems for the determination of real performance in personal dosimetry. (author)

Thermoluminescent dosimetry and assessment of personal dose

International Nuclear Information System (INIS)

Boas, J.F.; Martin, L.J.; Young, J.G.

1982-01-01

Thermoluminescence is discussed in terms of the energy band structure of a crystalline solid and the trapping of charge carriers by point defects. Some general properties of thermoluminescent materials used for dosimetry are outlined, with thermoluminescence of CaSO 4 :Dy being described in detail. The energy response function and the modification of the energy response of a dosimeter by shielding are discussed. The final section covers the connection between exposure, as recorded by a TLD badge, and the absorbed dose to various organs from gamma radiation in a uranium mine; the conversion from absorbed dose to dose equivalent; and uncertainties in assessment of dose equivalent

Polymer gel dosimetry

Energy Technology Data Exchange (ETDEWEB)

Baldock, C [Institute of Medical Physics, School of Physics, University of Sydney (Australia); De Deene, Y [Radiotherapy and Nuclear Medicine, Ghent University Hospital (Belgium); Doran, S [CRUK Clinical Magnetic Resonance Research Group, Institute of Cancer Research, Surrey (United Kingdom); Ibbott, G [Radiation Physics, UT M D Anderson Cancer Center, Houston, TX (United States); Jirasek, A [Department of Physics and Astronomy, University of Victoria, Victoria, BC (Canada); Lepage, M [Centre d' imagerie moleculaire de Sherbrooke, Departement de medecine nucleaire et de radiobiologie, Universite de Sherbrooke, Sherbrooke, QC (Canada); McAuley, K B [Department of Chemical Engineering, Queen' s University, Kingston, ON (Canada); Oldham, M [Department of Radiation Oncology, Duke University Medical Center, Durham, NC (United States); Schreiner, L J [Cancer Centre of South Eastern Ontario, Kingston, ON (Canada)], E-mail: c.baldock@physics.usyd.edu.au, E-mail: yves.dedeene@ugent.be

2010-03-07

Polymer gel dosimeters are fabricated from radiation sensitive chemicals which, upon irradiation, polymerize as a function of the absorbed radiation dose. These gel dosimeters, with the capacity to uniquely record the radiation dose distribution in three-dimensions (3D), have specific advantages when compared to one-dimensional dosimeters, such as ion chambers, and two-dimensional dosimeters, such as film. These advantages are particularly significant in dosimetry situations where steep dose gradients exist such as in intensity-modulated radiation therapy (IMRT) and stereotactic radiosurgery. Polymer gel dosimeters also have specific advantages for brachytherapy dosimetry. Potential dosimetry applications include those for low-energy x-rays, high-linear energy transfer (LET) and proton therapy, radionuclide and boron capture neutron therapy dosimetries. These 3D dosimeters are radiologically soft-tissue equivalent with properties that may be modified depending on the application. The 3D radiation dose distribution in polymer gel dosimeters may be imaged using magnetic resonance imaging (MRI), optical-computerized tomography (optical-CT), x-ray CT or ultrasound. The fundamental science underpinning polymer gel dosimetry is reviewed along with the various evaluation techniques. Clinical dosimetry applications of polymer gel dosimetry are also presented. (topical review)

Alanine dosimetry for clinical applications. Proceedings

International Nuclear Information System (INIS)

Anton, M.

2006-05-01

The following topics are dealt with: Therapy level alanine dosimetry at the UK Nationational Physical Laboratory, alanine as a precision validation tool for reference dosimetry, composition of alanine pellet dosimeters, the angular dependence of the alanine ESR spectrum, the CIAE alanine dosimeter for radiotherapy level, a correction for temporal evolution effects in alanine dosimetry, next-generation services foe e-traceability to ionization radiation national standards, establishing e-traceability to HIST high-dose measurement standards, alanine dosimetry of dose delivery from clinical accelerators, the e-scan alanine dosimeter reader, alanine dosimetry at ISS, verification of the integral delivered dose for IMRT treatment in the head and neck region with ESR/alanine dosimetry, alanine dosimetry in helical tomotherapy beams, ESR dosimetry research and development at the University of Palermo, lithium formate as a low-dose EPR radiation dosimeter, sensitivity enhancement of alanine/EPR dosimetry. (HSI)

Dosimetry of ionizing radiation

International Nuclear Information System (INIS)

Musilek, L.; Seda, J.; Trousil, J.

1992-01-01

The publication deals with a major field of ionizing radiation dosimetry, viz., integrating dosimetric methods, which are the basic means of operative dose determination. It is divided into the following sections: physical and chemical effects of ionizing radiation; integrating dosimetric methods for low radiation doses (film dosimetry, nuclear emulsions, thermoluminescence, radiophotoluminescence, solid-state track detectors, integrating ionization dosemeters); dosimetry of high ionizing radiation doses (chemical dosimetric methods, dosemeters based on the coloring effect, activation detectors); additional methods applicable to integrating dosimetry (exoelectron emission, electron spin resonance, lyoluminescence, etc.); and calibration techniques for dosimetric instrumentation. (Z.S.). 422 refs

In vivo dosimetry with semiconductors in medium dose rate (MDR) brachytherapy for cervical cancer.

Science.gov (United States)

Allahverdi, Mahmoud; Jaberi, Ramin; Aghili, Mehdi; Ghahremani, Fatemeh; Geraily, Ghazale

2013-03-01

This study was performed to evaluate the role of in vivo dosimetry with semiconductor detectors in gynaecological medium dose rate brachytherapy, and to compare the actual doses delivered to organs at risk (as measured using in vivo dosimetry) with those calculated during treatment planning. Doses to the rectum and bladder were measured in a group of patients with cervical carcinoma using semiconductor detectors and compared to the doses calculated using a treatment planning system. 36 applications of brachytherapy at dose rates of 1.8-2.3 Gy/h were performed in the patients. The mean differences between the measured and calculated doses were 3 % for the rectum and 11 % for the bladder. The main reason for the differences between the measured and calculated doses was patient movement. To reduce the risk of large errors in the dose delivered, in vivo dosimetry should be performed in addition to treatment planning system computations.

ASSESSMENT OF UNCERTAINTY IN THE RADIATION DOSES FOR THE TECHA RIVER DOSIMETRY SYSTEM

Energy Technology Data Exchange (ETDEWEB)

Napier, Bruce A.; Degteva, M. O.; Anspaugh, L. R.; Shagina, N. B.

2009-10-23

In order to provide more accurate and precise estimates of individual dose (and thus more precise estimates of radiation risk) for the members of the ETRC, a new dosimetric calculation system, the Techa River Dosimetry System-2009 (TRDS-2009) has been prepared. The deterministic version of the improved dosimetry system TRDS-2009D was basically completed in April 2009. Recent developments in evaluation of dose-response models in light of uncertain dose have highlighted the importance of different types of uncertainties in the development of individual dose estimates. These include uncertain parameters that may be either shared or unshared within the dosimetric cohort, and also the nature of the type of uncertainty as aleatory or epistemic and either classical or Berkson. This report identifies the nature of the various input parameters and calculational methods incorporated in the Techa River Dosimetry System (based on the TRDS-2009D implementation), with the intention of preparing a stochastic version to estimate the uncertainties in the dose estimates. This report reviews the equations, databases, and input parameters, and then identifies the author’s interpretations of their general nature. It presents the approach selected so that the stochastic, Monte-Carlo, implementation of the dosimetry System - TRDS-2009MC - will provide useful information regarding the uncertainties of the doses.

A radiochromic film based on leucomalachite green for high-dose dosimetry applications

International Nuclear Information System (INIS)

Soliman, Y.S.; Basfar, A.A.; Msalam, R.I.

2014-01-01

A colorless polyvinyl butyral film (PVB) based on radiation-sensitive dye of leucomalachite green (LMG) was investigated as a high-dose dosimeter for gamma radiation processing applications in the dose range of 3–150 kGy. The useful applications for such dose range are food irradiation treatment, medical devices sterilization and polymer modification. Gamma irradiation of the film induces a significant intensity of green color, which can be characterized by a main absorption band at 627 nm and a small band at 425 nm. The variation in response of irradiated film stored in the dark and under laboratory light illumination was less than 3% during the first 6 days of storage. The response of film during irradiation was slightly influenced by relative humidity in the range of 12–76%; however, it was significantly affected by temperature in the range of 5–40 °C. The radiation chemical yield was reported to be 6.76 × 10 −6  mol/J at the absorbed dose of 30 kGy for the film containing 6.5% of LMG dye. The overall uncertainty associated with routine dose monitoring would be less than 6% at a 95% confidence level if the dosimeter was being corrected for irradiation conditions and being calibrated with reference standard dosimeter in the production facility. - Highlights: • Development of a radiochromic film based on leucomalachite green dye for radiation processing dosimetry. • The dosimeter useful dose range is 3–150 kGy. • The dosimeter was slightly influenced by humidity levels during irradiation over the range of 12–76%. • The films stored in the dark have a good shelf life with a good stable response after irradiation. • Overall uncertainty of the dosimeter was less than 4.3% at σ

Transmission dose estimation algorithm for in vivo dosimetry

International Nuclear Information System (INIS)

Yun, Hyong Geun; Shin, Kyo Chul; Huh, Soon Nyung; Woo, Hong Gyun; Ha, Sung Whan; Lee, Hyoung Koo

2002-01-01

Measurement of transmission dose is useful for in vivo dosimetry of QA purpose. The objective of this study is to develope an algorithm for estimation of tumor dose using measured transmission dose for open radiation field. Transmission dose was measured with various field size (FS), phantom thickness (Tp), and phantom chamber distance (PCD) with an acrylic phantom for 6 MV and 10 MV X-ray. Source to chamber distance (SCD) was set to 150 cm. Measurement was conducted with a 0.6 cc Farmer type ion chamber. Using measured data and regression analysis, an algorithm was developed for estimation of expected reading of transmission dose. Accuracy of the algorithm was tested with flat solid phantom with various settings. The algorithm consisted of quadratic function of log(A/P) (where A/P is area-perimeter ratio) and tertiary function of PCD. The algorithm could estimate dose with very high accuracy for open square field, with errors within ±0.5%. For elongated radiation field, the errors were limited to ±1.0%. The developed algorithm can accurately estimate the transmission dose in open radiation fields with various treatment settings

Transmission dose estimation algorithm for in vivo dosimetry

Energy Technology Data Exchange (ETDEWEB)

Yun, Hyong Geun; Shin, Kyo Chul [Dankook Univ., Seoul (Korea, Republic of); Huh, Soon Nyung; Woo, Hong Gyun; Ha, Sung Whan [Seoul National Univ., Seoul (Korea, Republic of); Lee, Hyoung Koo [Catholic Univ., Seoul (Korea, Republic of)

2002-07-01

Measurement of transmission dose is useful for in vivo dosimetry of QA purpose. The objective of this study is to develope an algorithm for estimation of tumor dose using measured transmission dose for open radiation field. Transmission dose was measured with various field size (FS), phantom thickness (Tp), and phantom chamber distance (PCD) with an acrylic phantom for 6 MV and 10 MV X-ray. Source to chamber distance (SCD) was set to 150 cm. Measurement was conducted with a 0.6 cc Farmer type ion chamber. Using measured data and regression analysis, an algorithm was developed for estimation of expected reading of transmission dose. Accuracy of the algorithm was tested with flat solid phantom with various settings. The algorithm consisted of quadratic function of log(A/P) (where A/P is area-perimeter ratio) and tertiary function of PCD. The algorithm could estimate dose with very high accuracy for open square field, with errors within {+-}0.5%. For elongated radiation field, the errors were limited to {+-}1.0%. The developed algorithm can accurately estimate the transmission dose in open radiation fields with various treatment settings.

Experimental 3D dosimetry around a high-dose-rate clinical 192Ir source using a polyacrylamide gel (PAG) dosimeter

International Nuclear Information System (INIS)

McJury, M.; Tapper, P.D.; Griffin, S.; Cosgrove, V.P.; Webb, S.; Murphy, P.S.; Leach, M.O.; Oldham, M.

1999-01-01

It is well known that the experimental dosimetry of brachytherapy sources presents a challenge. Depending on the particular dosimeter used, measurements can suffer from poor spatial resolution (ion chambers), lack of 3D information (film) or errors due to the presence of the dosimeter itself distorting the radiation flux. To avoid these problems, we have investigated the dosimetry of a clinical 192 Ir source using a polyacrylamide gel (PAG) dosimeter. Experimental measurements of dose versus radial distance from the centre of the source (cross-line plots) were compared with calculations produced with a Nucletron NPS planning system. Good agreement was found between the planning system and gel measurements in planes selected for analysis. Gel dosimeter measurements in a coronal plane through the phantom showed a mean difference between measured absorbed dose and calculated dose of 0.17 Gy with SD=0.13Gy. Spatially, the errors at the reference point remain within one image pixel (1.0 mm). The use of polymer gel dosimetry shows promise for brachytherapy applications, offering complete, three-dimensional dose information, good spatial resolution and small measurement errors. Measurements close to the source, however, are difficult, due to some of the limiting properties of the polyacrylamide gel. (author)

Use of CT or MR dosimetry in high dose rate (HDR) brachytherapy for prostate cancer

International Nuclear Information System (INIS)

Liu, C.; Das, R.; See, A.; Duchesne, G.M.; Van Dyk, S.; Tai, K.H.

2003-01-01

Brachytherapy (BT) has, in recent years, become a well-utilised treatment option for prostate cancer. Tumour control probability relies on accurate dosimetry, which in turn relies on the accurate definition of the prostate gland. In external beam radiotherapy and BT, MRI has been shown to be a superior imaging modality when delineating the prostate gland especially at the apex. To date, data on MRI planning in prostate BT has focussed mainly on permanent interstitial implants. No data currently exists comparing MRI vs CT planning in HDR BT and its subsequent impact on prostate dosimetry. To determine the effects of MRI vs CT in HDR BT with respect to prostatic volumes and normal tissue doses, with the evaluations made using dose-volume histograms (DVH). Dosimetry parameters derived using CT and MRI (T2 weighted) scans of 11 patients who had received TRUS guided implants for HDR BT, were compared using the PlatoTM computer planning system. Treatment plans were generated on volumes marked by the same radiation oncologist for each patient. Comparison was made of the treatment plans (dosimetry) between: 1. CT generated plans; 2. CT generated plans assessed using MRI marked volumes and 3. MRI generated plans. We confirm the previously reported results that CT scans can overestimate prostatic volumes compared with MRI. Variations were noted in CT and MRI based plans that may allow improved sparing of the rectum and urethra when using MRI planning. The main disadvantages of using MRI scans are access to facilities as well as identifying a dummy source to adequately define the tips of our catheters. It is feasible to utilise MRI scans for HDR BT planning. The clearer definition of anatomical structures has added advantages when contouring the prostate

Dosimetry as an integral part of radiation processing

International Nuclear Information System (INIS)

Zagorski, Z.P.

1999-01-01

Different connections between high-dose dosimetry and radiation processing are discussed. Radiation processing cannot be performed without proper dosimetry. Accurate high dose and high dose rate dosimetry exhibits several aspects: first of all it is the preservation of the quality of the product, then fulfillment of legal aspects and last but not the least the safety of processing. Further, seldom discussed topics are as follow: dosimetric problems occurring with double-side EB irradiations, discussed in connection with the deposition of electric charge during electron beam irradiation. Although dosimetry for basic research and for medical purposes are treated here only shortly, some conclusions reached from these fields are considered in dosimetry for radiation processing. High-dose dosimetry of radiation has become a separate field, with many papers published every year, but applied dosimetric projects are usually initiated by a necessity of particular application. (author)

High-density polyethylene dosimetry by transvinylene FTIR analysis

DEFF Research Database (Denmark)

McLaughlin, W.L.; Silverman, J.; Al-Sheikhly, M.

1999-01-01

and electrons. The useful dose range of 0.053 cm thick high-density polyethylene film (rho = 0.961 g cm(-3); melt index = 0.8 dg min(-1)), for irradiations by (60)Co gamma radiation and 2.0 and 0.4 MeV electron beams in deaerated atmosphere (Na gas), is about 50-10(3) kGy for FTIR transvinylene......The formation of transvinylene unsaturation, -CH=CH-, due to free-radical or cationic-initiated dehydrogenation by irradiation, is a basic reaction in polyethylene and is useful for dosimetry at high absorbed doses. The radiation-enhanced infrared absorption having a maximum at nu = 965 cm......(-l) (lambda = 10.36 mu m) is stable in air and can be measured by Fourier-transform infrared (FTIR) spectrophotometry. The quantitative analysis is a useful means of product end-point dosimetry for radiation processing with gamma rays and electrons, where polyethylene is a component of the processed product...

Validating dose rate calibration of radiotherapy photon beams through IAEA/WHO postal audit dosimetry service

International Nuclear Information System (INIS)

Jangda, A.Q.; Hussein, S.

2012-01-01

In external beam radiation therapy (EBRT), the quality assurance (QA) of the radiation beam is crucial to the accurate delivery of the prescribed dose to the patient. One of the dosimetric parameters that require monitoring is the beam output, specified as the dose rate on the central axis under reference conditions. The aim of this project was to validate dose rate calibration of megavoltage photon beams using the International Atomic Energy Agency (IAEA)/World Health Organisation (WHO) postal audit dosimetry service. Three photon beams were audited: a 6 MV beam from the low-energy linac and 6 and 18 MV beams from a dual high-energy linac. The agreement between our stated doses and the IAEA results was within 1% for the two 6 MV beams and within 2% for the 18 MV beam. The IAEA/WHO postal audit dosimetry service provides an independent verification of dose rate calibration protocol by an international facility. (author)

Validating dose rate calibration of radiotherapy photon beams through IAEA/WHO postal audit dosimetry service.

Science.gov (United States)

Jangda, Abdul Qadir; Hussein, Sherali

2012-05-01

In external beam radiation therapy (EBRT), the quality assurance (QA) of the radiation beam is crucial to the accurate delivery of the prescribed dose to the patient. One of the dosimetric parameters that require monitoring is the beam output, specified as the dose rate on the central axis under reference conditions. The aim of this project was to validate dose rate calibration of megavoltage photon beams using the International Atomic Energy Agency (IAEA)/World Health Organisation (WHO) postal audit dosimetry service. Three photon beams were audited: a 6 MV beam from the low-energy linac and 6 and 18 MV beams from a dual high-energy linac. The agreement between our stated doses and the IAEA results was within 1% for the two 6 MV beams and within 2% for the 18 MV beam. The IAEA/WHO postal audit dosimetry service provides an independent verification of dose rate calibration protocol by an international facility.

High level radiation dosimetry in biomedical research

International Nuclear Information System (INIS)

Inada, Tetsuo

1979-01-01

The physical and biological dosimetries relating to cancer therapy with radiation were taken up at the first place in the late intercomparison on high LET radiation therapy in Japan-US cancer research cooperative study. The biological dosimetry, the large dose in biomedical research, the high dose rate in biomedical research and the practical dosimeters for pulsed neutrons or protons are outlined with the main development history and the characteristics which were obtained in the relating experiments. The clinical neutron facilities in the US and Japan involved in the intercomparison are presented. Concerning the experimental results of dosimeters, the relation between the R.B.E. compared with Chiba (Cyclotron in National Institute of Radiological Sciences) and the energy of deuterons or protons used for neutron production, the survival curves of three cultured cell lines derived from human cancers, after the irradiation of 250 keV X-ray, cyclotron neutrons of about 13 MeV and Van de Graaff neutrons of about 2 MeV, the hatchability of dry Artemia eggs at the several depths in an absorber stack irradiated by 60 MeV proton beam of 40, 120 and 200 krad, the peak skin reaction of mouse legs observed at various sets of average and instantaneous dose rates, and the peak skin reaction versus three instantaneous dose rates at fixed average dose rate of 7,300 rad/min are shown. These actual data were evaluated numerically and in relation to the physical meaning from the viewpoint of the fundamental aspect of cancer therapy, comparing the Japanese measured values to the US data. The discussion record on the high dose rate effect of low LET particles on biological substances and others is added. (Nakai, Y.)

The international protocol for the dosimetry of external radiotherapy beams based on standards of absorbed dose to water

International Nuclear Information System (INIS)

Andreo, P.

2001-01-01

An International Code of Practice (CoP, or dosimetry protocol) for external beam radiotherapy dosimetry based on standards of absorbed dose to water has been published by the IAEA on behalf of IAEA, WHO, PAHO and ESTRO. The CoP provides a systematic and internationally unified approach for the determination of the absorbed dose to water in reference conditions with radiotherapy beams. The development of absorbed-dose-to-water standards for high-energy photons and electrons offers the possibility of reducing the uncertainty in the dosimetry of radiotherapy beams. Many laboratories already provide calibrations at the radiation quality of 60Co gamma-rays and some have extended calibrations to high-energy photon and electron beams. The dosimetry of kilovoltage x-rays, as well as that of proton and ion beams can also be based on these standards. Thus, a coherent dosimetry system based on the same formalism is achieved for practically all radiotherapy beams. The practical use of the CoP as simple. The document is formed by a set of different CoPs for each radiation type, which include detailed procedures and worksheets. All CoPs are based on ND,w chamber calibrations at a reference beam quality Qo, together with radiation beam quality correction factors kQ preferably measured directly for the user's chamber in a standards laboratory. Calculated values of kQ are provided together with their uncertainty estimates. Beam quality specifiers are 60Co, TPR20,10 (high-energy photons), R50 (electrons), HVL and kV (x-rays) and Rres (protons and ions) [es

Development and current state of dosimetry in Cuba

International Nuclear Information System (INIS)

Prieto Miranda, E.F.; Cuesta Fuente, G.; Chavez Ardanza, A.

1999-01-01

In Cuba, the application of the radiation technologies has been growing in the last years, and at present there are several dosimetry systems with different ranges of absorbed dose. Diverse researches were carried out on high dose dosimetry with the following dosimetry systems: Fricke, ceric-cerous sulfate, ethanol-chlorobenzene, cupric sulfate and Perspex (Red 4034 AE and Clear HX). In this paper the development achieved during the last 15 years in the high dose dosimetry for radiation processing in Cuba is presented, as well as, the current state of different dosimetry systems employed for standardization and for process control. The paper also reports the results of dosimetry intercomparison studies that were performed with the Ezeiza Atomic Center of Argentine and the International Dose Assurance Service (IDAS) of IAEA. (author)

Calibration of high-dose radiation facilities (Handbook)

International Nuclear Information System (INIS)

Gupta, B.L.; Bhat, R.M.

1986-01-01

In India at present several high intensity radiation sources are used. There are 135 teletheraphy machines and 65 high intensity cobalt-60 sources in the form of gamma chambers (2.5 Ci) and PANBIT (50 Ci). Several food irradiation facilities and a medical sterilization plant ISOMED are also in operation. The application of these high intensity sources involve a wide variation of dose from 10 Gy to 100 kGy. Accurate and reproducible radiation dosimetry is essential in the use of these sources. This handbook is especially compiled for calibration of high-dose radiation facilities. The first few chapters discuss such topics as interaction of radiation with matter, radiation chemistry, radiation processing, commonly used high intensity radiation sources and their special features, radiation units and dosimetry principles. In the chapters which follow, chemical dosimeters are discussed in detail. This discussion covers Fricke dosimeter, FBX dosimeter, ceric sulphate dosimeter, free radical dosimetry, coloured indicators for irrdiation verification. A final chapter is devoted to practical hints to be followed in calibration work. (author)

Impact of oedema on implant geometry and dosimetry for temporary high dose rate brachytherapy of the prostate

International Nuclear Information System (INIS)

Kiffer, J.D.; Schumer, W.A.; Mantle, C.A.; McKenzie, B.J.; Feigen, M.; Quong, G.G.; Waterman, F.M.

2003-01-01

The optimal timing of dosimetry for permanent seed prostatic implants remains contentious given the half life of post-implant oedema resolution. The aim of this study was to establish whether prostatic oedematous change over the duration of a temporary high dose rate (HDR) interstitial brachytherapy (BR) boost would result in significant needle displacement, and whether this change in geometry would influence dosimetry. Two CT scans, one for dosimetric purposes on the day of the implant and the second just prior to implant removal, were obtained for four patients receiving transperineal interstitial prostate brachytherapy. The relative changes in cross-sectional dimensions of the implants were calculated by establishing the change in mean radial distance (MRD) of the needle positions from the geometric centre of the implant for each patient's pair of CT studies. The treatment plan, as calculated from the first CT scan, was used in the second set of CT images to allow a comparison of dose distribution. The percentage change in MRD over the duration of the temporary implants ranged from -1.91% to 1.95%. The maximum change in estimated volume was 3.94%. Dosimetric changes were negligible. In the four cases studied, the degree of oedematous change and consequent displacement of flexiguide needle positions was negligible and did not impact on the dosimetry. The rate and direction of oedematous change can be extremely variable but on the basis of the four cases studied and the results of a larger recent study, it might not be necessary to re-image patients for dosimetric purposes over the duration of a fractionated HDR BT boost to the prostate where flexiguide needles are utilized. Nevertheless, further investigation with larger patient numbers is required. Copyright (2003) Blackwell Science Pty Ltd

Concept and computation of radiation dose at high energies

International Nuclear Information System (INIS)

Sarkar, P.K.

2010-01-01

Computational dosimetry, a subdiscipline of computational physics devoted to radiation metrology, is determination of absorbed dose and other dose related quantities by numbers. Computations are done separately both for external and internal dosimetry. The methodology used in external beam dosimetry is necessarily a combination of experimental radiation dosimetry and theoretical dose computation since it is not feasible to plan any physical dose measurements from inside a living human body

Dosimetry; La dosimetrie

Energy Technology Data Exchange (ETDEWEB)

Le Couteulx, I.; Apretna, D.; Beaugerie, M.F. [Electricite de France (EDF), 75 - Paris (France)] [and others

2003-07-01

Eight articles treat the dosimetry. Two articles evaluate the radiation doses in specific cases, dosimetry of patients in radiodiagnosis, three articles are devoted to detectors (neutrons and x and gamma radiations) and a computer code to build up the dosimetry of an accident due to an external exposure. (N.C.)

Fifth international radiopharmaceutical dosimetry symposium

International Nuclear Information System (INIS)

Watson, E.E.; Schlafke-Stelson, A.T.

1992-05-01

This meeting was held to exchange information on how to get better estimates of the radiation absorbed dose. There seems to be a high interest of late in patient dosimetry; discussions were held in the light of revised risk estimates for radiation. Topics included: Strategies of Dose Assessment; Dose Estimation for Radioimmunotherapy; Dose Calculation Techniques and Models; Dose Estimation for Positron Emission Tomography (PET); Kinetics for Dose Estimation; and Small Scale Dosimetry and Microdosimetry. (VC)

High sensitive radiation detector for radiology dosimetry

Energy Technology Data Exchange (ETDEWEB)

Valente, M.; Malano, F. [Instituto de Fisica Enrique Gaviola, Oficina 102 FaMAF - UNC, Av. Luis Medina Allende, Ciudad Universitaria, 5000 Cordoba (Argentina); Molina, W.; Vedelago, J., E-mail: valente@famac.unc.edu.ar [Laboratorio de Investigaciones e Instrumentacion en Fisica Aplicada a la Medicina e Imagenes por Rayos X, Laboratorio 448 FaMAF - UNC, Ciudad Universitaria, 5000 Cordoba (Argentina)

2014-08-15

Fricke solution has a wide range of applications as radiation detector and dosimetry. It is particularly appreciated in terms of relevant comparative advantages, like tissue equivalence when prepared in aqueous media like gel matrix, continuous mapping capability, dose rate recorded and incident direction independence as well as linear dose response. This work presents the development and characterization of a novel Fricke gel system, based on modified chemical compositions making possible its application in clinical radiology. Properties of standard Fricke gel dosimeter for high dose levels are used as starting point and suitable chemical modifications are introduced and carefully investigated in order to attain high resolution for low dose ranges, like those corresponding to radiology interventions. The developed Fricke gel radiation dosimeter system achieves the expected typical dose dependency, actually showing linear response in the dose range from 20 up to 4000 mGy. Systematic investigations including several chemical compositions are carried out in order to obtain a good enough dosimeter response for low dose levels. A suitable composition among those studied is selected as a good candidate for low dose level radiation dosimetry consisting on a modified Fricke solution fixed to a gel matrix containing benzoic acid along with sulfuric acid, ferrous sulfate, xylenol orange and ultra-pure reactive grade water. Dosimeter samples are prepared in standard vials for its in phantom irradiation and further characterization by spectrophotometry measuring visible light transmission and absorbance before and after irradiation. Samples are irradiated by typical kV X-ray tubes and calibrated Farmer type ionization chamber is used as reference to measure dose rates inside phantoms in at vials locations. Once sensitive material composition is already optimized, dose-response curves show significant improvement regarding overall sensitivity for low dose levels. According to

High sensitive radiation detector for radiology dosimetry

International Nuclear Information System (INIS)

Valente, M.; Malano, F.; Molina, W.; Vedelago, J.

2014-08-01

Fricke solution has a wide range of applications as radiation detector and dosimetry. It is particularly appreciated in terms of relevant comparative advantages, like tissue equivalence when prepared in aqueous media like gel matrix, continuous mapping capability, dose rate recorded and incident direction independence as well as linear dose response. This work presents the development and characterization of a novel Fricke gel system, based on modified chemical compositions making possible its application in clinical radiology. Properties of standard Fricke gel dosimeter for high dose levels are used as starting point and suitable chemical modifications are introduced and carefully investigated in order to attain high resolution for low dose ranges, like those corresponding to radiology interventions. The developed Fricke gel radiation dosimeter system achieves the expected typical dose dependency, actually showing linear response in the dose range from 20 up to 4000 mGy. Systematic investigations including several chemical compositions are carried out in order to obtain a good enough dosimeter response for low dose levels. A suitable composition among those studied is selected as a good candidate for low dose level radiation dosimetry consisting on a modified Fricke solution fixed to a gel matrix containing benzoic acid along with sulfuric acid, ferrous sulfate, xylenol orange and ultra-pure reactive grade water. Dosimeter samples are prepared in standard vials for its in phantom irradiation and further characterization by spectrophotometry measuring visible light transmission and absorbance before and after irradiation. Samples are irradiated by typical kV X-ray tubes and calibrated Farmer type ionization chamber is used as reference to measure dose rates inside phantoms in at vials locations. Once sensitive material composition is already optimized, dose-response curves show significant improvement regarding overall sensitivity for low dose levels. According to

Dosimetric advancement of high-dose-rate after-loading 192Ir source

International Nuclear Information System (INIS)

Zhang Shuxu; Li Wenhua; Xu Hairong

2004-01-01

High-dose-rate (HDR) 192 Ir source is a nuclide commonly used in the brachytherapy system. The basic dosimetry data of the near source area is usually measured by pin ion chambers or TLD techniques, but these methods have a lower spatial resolution than Electron spin resonance (ESR) dosimetry which has a spatial resolution of 156 μm, and the Monte Carlo photon transport simulations are taken as the golden standard of those measures. The precision in two-dimensional dose distribution measured by GafChromic film is reported to be 1.0%. In vivo dosimetry using TLD during HDR intracavitary after-loading brachytherapy is a good predictor of late rectal complications. The accuracy of magnetic resonance imaging (MRI) Fricke-gel dosimetry for three-dimensional dose distribution is about 2.5% with a spatial resolution of 1.56 mm. The optical computed tomography polymer gel dosimetry has a unique advance than MRI gel dosimetry

137Cs source dose distribution using the Fricke Xylenol Gel dosimetry

International Nuclear Information System (INIS)

Sato, R.; De Almeida, A.; Moreira, M.V.

2009-01-01

Dosimetric measurements close to radioisotope sources, such as those used in brachytherapy, require high spatial resolution to avoid incorrect results in the steep dose gradient region. In this work the Fricke Xylenol Gel dosimeter was used to obtain the spatial dose distribution. The readings from a 137 Cs source were performed using two methods, visible spectrophotometer and CCD camera images. Good agreement with the Sievert summation method was found for the transversal axis dose profile within uncertainties of 4% and 5%, for the spectrophotometer and CCD camera respectively. Our results show that the dosimeter is adequate for brachytherapy dosimetry and, owing to its relatively fast and easy preparation and reading, it is recommended for quality control in brachytherapy applications.

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

International Nuclear Information System (INIS)

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

2003-01-01

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

Natural dose level determination at Johor State with thermoluminescence dosimetry

International Nuclear Information System (INIS)

Ahmad Termizi Ramli; Yusof Jasman

1995-01-01

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

Optimal registration conditions for tooth EPR dosimetry at low accumulated dose

International Nuclear Information System (INIS)

Galtsev, V.E.; Galtseva, E.V.; Lebedev, Y.S.

1997-01-01

The spectrum registration under rapid passage conditions (the second harmonic phase quadrature of the absorption signal) allows one to enhance substantially the sensitivity of tooth enamel and bone EPR dosimetry at a low accumulated dose. In the present work the dependencies of the radiation and background signals on EPR spectrometer parameters are described and the optimal conditions in RPM for EPR dosimetry are obtained. (Author)

Dose evaluation of three-dimensional small animal phantom with film dosimetry

International Nuclear Information System (INIS)

Han, Su Chul; Park, Seung Woo

2017-01-01

The weight of small animal dosimetry has been continuously increased in pre-clinical studies using radiation in small animals. In this study, three-dimensional(3D) small animal phantom was fabricated using 3D printer which has been continuously used and studied in the various fields. The absorbed dose of 3D animal phantom was evaluated by film dosimetry. Previously, the response of film was obtained from the materials used for production of 3D small animal phantom and compared with the bolus used as the tissue equivalent material in the radiotherapy. When irradiated with gamma rays from 0.5 Gy to 6 Gy, it was confirmed that there was a small difference of less than 1% except 0.5 Gy dose. And when small animal phantom was irradiated with 5 Gy, the difference between the irradiated dose and calculated dose from film was within 2%. Based on this study, it would be possible to increase the reliability of dose in pre-clinical studies using irradiation in small animals by evaluating dose of 3D small animal phantom

Dose evaluation of three-dimensional small animal phantom with film dosimetry

Energy Technology Data Exchange (ETDEWEB)

Han, Su Chul [Div. of Medical Radiation Equipment, Korea Institute of Radiological and Medical Sciences, Seoul (Korea, Republic of); Park, Seung Woo [Radilogcial and Medico-Oncological Sciences, University of Sciences and Technology, Daejeon (Korea, Republic of)

2017-03-15

The weight of small animal dosimetry has been continuously increased in pre-clinical studies using radiation in small animals. In this study, three-dimensional(3D) small animal phantom was fabricated using 3D printer which has been continuously used and studied in the various fields. The absorbed dose of 3D animal phantom was evaluated by film dosimetry. Previously, the response of film was obtained from the materials used for production of 3D small animal phantom and compared with the bolus used as the tissue equivalent material in the radiotherapy. When irradiated with gamma rays from 0.5 Gy to 6 Gy, it was confirmed that there was a small difference of less than 1% except 0.5 Gy dose. And when small animal phantom was irradiated with 5 Gy, the difference between the irradiated dose and calculated dose from film was within 2%. Based on this study, it would be possible to increase the reliability of dose in pre-clinical studies using irradiation in small animals by evaluating dose of 3D small animal phantom.

MO-B-BRB-04: 3D Dosimetry in End-To-End Dosimetry QA

Energy Technology Data Exchange (ETDEWEB)

Ibbott, G. [UT MD Anderson Cancer Center (United States)

2016-06-15

Full three-dimensional (3D) dosimetry using volumetric chemical dosimeters probed by 3D imaging systems has long been a promising technique for the radiation therapy clinic, since it provides a unique methodology for dose measurements in the volume irradiated using complex conformal delivery techniques such as IMRT and VMAT. To date true 3D dosimetry is still not widely practiced in the community; it has been confined to centres of specialized expertise especially for quality assurance or commissioning roles where other dosimetry techniques are difficult to implement. The potential for improved clinical applicability has been advanced considerably in the last decade by the development of improved 3D dosimeters (e.g., radiochromic plastics, radiochromic gel dosimeters and normoxic polymer gel systems) and by improved readout protocols using optical computed tomography or magnetic resonance imaging. In this session, established users of some current 3D chemical dosimeters will briefly review the current status of 3D dosimetry, describe several dosimeters and their appropriate imaging for dose readout, present workflow procedures required for good dosimetry, and analyze some limitations for applications in select settings. We will review the application of 3D dosimetry to various clinical situations describing how 3D approaches can complement other dose delivery validation approaches already available in the clinic. The applications presented will be selected to inform attendees of the unique features provided by full 3D techniques. Learning Objectives: L. John Schreiner: Background and Motivation Understand recent developments enabling clinically practical 3D dosimetry, Appreciate 3D dosimetry workflow and dosimetry procedures, and Observe select examples from the clinic. Sofie Ceberg: Application to dynamic radiotherapy Observe full dosimetry under dynamic radiotherapy during respiratory motion, and Understand how the measurement of high resolution dose data in an

Personal Doses Recorded by Service of Personal Dosimetry

International Nuclear Information System (INIS)

Mihai, F.; Gheorghiu, A.; Stochioiu, A.; Udup, E.

2009-01-01

In this work we present occupational exposure statistics on: number of workers on different dose ranges; average of the mean annual doses (MAD) over the period 2000 - 2007 on all monitored workers as well as on those who have been received doses over the minimum detection limit (MDL). The statistic is made on different types of nuclear laboratories. The data are obtained on almost 1000 workers occupational exposure to different sources of radiations (gamma and X-ray) and monitored by Photo dosimetry Survey Unit, IFIN - HH. These results point out the evolution of the individual doses received during eight years and can be used to analyse the need of radiation protection in different nuclear facilities from Romania

Dosimetry control for radiation processing - basic requirements and standards

International Nuclear Information System (INIS)

Ivanova, M.; Tsrunchev, Ts.

2004-01-01

A brief review of the basic international codes and standards for dosimetry control for radiation processing (high doses dosimetry), setting up a dosimetry control for radiation processing and metrology control of the dosimetry system is made. The present state of dosimetry control for food processing and the Bulgarian long experience in food irradiation (three irradiation facilities are operational at these moment) are presented. The absence of neither national standard for high doses nor accredited laboratory for calibration and audit of radiation processing dosimetry systems is also discussed

A mathematical approach to optimal selection of dose values in the additive dose method of ERP dosimetry

International Nuclear Information System (INIS)

Hayes, R.B.; Haskell, E.H.; Kenner, G.H.

1996-01-01

Additive dose methods commonly used in electron paramagnetic resonance (EPR) dosimetry are time consuming and labor intensive. We have developed a mathematical approach for determining optimal spacing of applied doses and the number of spectra which should be taken at each dose level. Expected uncertainitites in the data points are assumed to be normally distributed with a fixed standard deviation and linearity of dose response is also assumed. The optimum spacing and number of points necessary for the minimal error can be estimated, as can the likely error in the resulting estimate. When low doses are being estimated for tooth enamel samples the optimal spacing is shown to be a concentration of points near the zero dose value with fewer spectra taken at a single high dose value within the range of known linearity. Optimization of the analytical process results in increased accuracy and sample throughput

Secondary standard dosimetry system with automatic dose/rate calculation

International Nuclear Information System (INIS)

Duftschmid, K.E.; Bernhart, J.; Stehno, G.; Klosch, W.

1980-01-01

A versatile and automated secondary standard instrument has been designed for quick and accurate dose/rate measurement in a wide range of radiation intensity and quality (between 1 μR and 100 kR; 0.2 nC/kg - 20C/kg) for protection and therapy level dosimetry. The system is based on a series of secondary standard ionization chambers connected to a precision digital current integrator with microprocessor circuitry for data evaluation and control. Input of measurement parameters and calibration factors stored in an exchangeable memory chip provide computation of dose/rate values in the desired units. The ionization chambers provide excellent long-term stability and energy response and can be used with internal check sources to test validity of calibration. The system is a useful tool particularly for daily measurements in a secondary standard dosimetry laboratory or radiation therapy center. (H.K.)

The sensitivity analysis of tooth enamel to the absorbed dose for the application to EPR dosimetry

International Nuclear Information System (INIS)

Hong, Dae Seok; Lee, Kun Jai; Cho, Young Hwan

2002-01-01

Electron Paramagnetic Resonance (EPR) spectroscopy is one of the methods applicable to retrospective dosimetry. The retrospective dosimetry is a process that is a part of dose reconstruction for estimation of exposed dose occurred years before the estimation. Many techniques can be used to the retrospective dosimetry. As a physical method, EPR analysis of biological material measures the quantity of free radicals generated in the material from the interaction of radiation and material. Since the later 80s, in many countries, EPR dosimetry with tooth enamel has been studied and applied for the retrospective dosimetry. In the consideration of the biological materials for EPR dosimetry, human fingernail, hair, bone and tooth are generally considered. The tooth can be separated as enamel, dentine and cementum. Among the three parts, enamel shows the best sensitivity to the absorbed dose and is most widely used. In this study, the characteristics of tooth enamel for EPR dosimetry is examined and experimented. At the experiment, for easy separation, tooth was cut into 4 parts and then each part is treated by ultrasonic vibration in NaOH liquid to reduce mechanically induced noise in the corresponding signal. After the separation of the enamel from dentine, background EPR signal is measured and then radiation-induced EPR spectrum is estimated

The IAEA/WHO TLD postal dose quality audits for radiotherapy: a perspective of dosimetry practices at hospitals in developing countries

International Nuclear Information System (INIS)

Izewska, Joanna; Andreo, Pedro; Vatnitsky, Stanislav; Shortt, Ken R.

2003-01-01

Background and purpose: The IAEA/WHO TLD postal programme for external audits of the calibration of high-energy photon beams used in radiotherapy has been in operation since 1969. This work presents a survey of the 1317 TLD audits carried out during 1998-2001. The TLD results are discussed from the perspective of the dosimetry practices in hospitals in developing countries, based on the information provided by the participants in their TLD data sheets. Materials and methods: A detailed analysis of the TLD data sheets is systematically performed at the IAEA. It helps to trace the source of any discrepancy between the TLD measured dose and the user stated dose, and also provides information on equipment, dosimetry procedures and the use of codes of practice in the countries participating in the IAEA/WHO TLD audits. Result: The TLD results are within the 5% acceptance limit for 84% of the participants. The results for accelerator beams are typically better than for Co-60 units. Approximately 75% of participants reported dosimetry data, including details on their procedure for dose determination from ionisation chamber measurements. For the remaining 25% of hospitals, who did not submit these data, the results are poorer than the global TLD results. Most hospitals have Farmer type ionisation chambers calibrated in terms of air kerma by a standards laboratory. Less than 10% of the hospitals use new codes of practice based on standards of absorbed dose to water. Conclusion: Despite the differences in dosimetry equipment, traceability to different standards laboratories and uncertainties arising from the use of various dosimetry codes of practice, the determination of absorbed dose to water for photon beams typically agrees within 2% among hospitals. Correct implementation of any of the dosimetry protocols should ensure that significant errors in dosimetry are avoided

Extension of the biological effective dose to the MIRD schema and possible implications in radionuclide therapy dosimetry

International Nuclear Information System (INIS)

Baechler, Sebastien; Hobbs, Robert F.; Prideaux, Andrew R.; Wahl, Richard L.; Sgouros, George

2008-01-01

In dosimetry-based treatment planning protocols, patients with rapid clearance of the radiopharmaceutical require a larger amount of initial activity than those with slow clearance to match the absorbed dose to the critical organ. As a result, the dose-rate to the critical organ is higher in patients with rapid clearance and may cause unexpected toxicity compared to patients with slow clearance. In order to account for the biological impact of different dose-rates, radiobiological modeling is beginning to be applied to the analysis of radionuclide therapy patient data. To date, the formalism used for these analyses is based on kinetics derived from activity in a single organ, the target. This does not include the influence of other source organs to the dose and dose-rate to the target organ. As a result, only self-dose irradiation in the target organ contributes to the dose-rate. In this work, the biological effective dose (BED) formalism has been extended to include the effect of multiple source organ contributions to the net dose-rate in a target organ. The generalized BED derivation has been based on the Medical Internal Radionuclide Dose Committee (MIRD) schema assuming multiple source organs following exponential effective clearance of the radionuclide. A BED-based approach to determine the largest safe dose to critical organs has also been developed. The extended BED formalism is applied to red marrow dosimetry, as well as kidney dosimetry considering the cortex and the medulla separately, since both those organs are commonly dose limiting in radionuclide therapy. The analysis shows that because the red marrow is an early responding tissue (high α/β), it is less susceptible to unexpected toxicity arising from rapid clearance of high levels of administered activity in the marrow or in the remainder of the body. In kidney dosimetry, the study demonstrates a complex interplay between clearance of activity in the cortex and the medulla, as well as the initial

Dosimetry

International Nuclear Information System (INIS)

Rezende, D.A.O. de

1976-01-01

The fundamental units of dosimetry are defined, such as exposure rate, absorbed dose and equivalent dose. A table is given of relative biological effectiveness values for the different types of radiation. The relation between the roentgen and rad units is calculated and the concepts of physical half-life, biological half-life and effective half-life are discussed. Referring to internal dosimetry, a mathematical treatment is given to β particle-and γ radiation dosimetry. The absorbed dose is calculated and a practical example is given of the calculation of the exposure and of the dose rate for a gama source [pt

Biological dosimetry of ionizing radiation: Evaluation of the dose with cytogenetic methodologies by the construction of calibration curves

Science.gov (United States)

Zafiropoulos, Demetre; Facco, E.; Sarchiapone, Lucia

2016-09-01

In case of a radiation accident, it is well known that in the absence of physical dosimetry biological dosimetry based on cytogenetic methods is a unique tool to estimate individual absorbed dose. Moreover, even when physical dosimetry indicates an overexposure, scoring chromosome aberrations (dicentrics and rings) in human peripheral blood lymphocytes (PBLs) at metaphase is presently the most widely used method to confirm dose assessment. The analysis of dicentrics and rings in PBLs after Giemsa staining of metaphase cells is considered the most valid assay for radiation injury. This work shows that applying the fluorescence in situ hybridization (FISH) technique, using telomeric/centromeric peptide nucleic acid (PNA) probes in metaphase chromosomes for radiation dosimetry, could become a fast scoring, reliable and precise method for biological dosimetry after accidental radiation exposures. In both in vitro methods described above, lymphocyte stimulation is needed, and this limits the application in radiation emergency medicine where speed is considered to be a high priority. Using premature chromosome condensation (PCC), irradiated human PBLs (non-stimulated) were fused with mitotic CHO cells, and the yield of excess PCC fragments in Giemsa stained cells was scored. To score dicentrics and rings under PCC conditions, the necessary centromere and telomere detection of the chromosomes was obtained using FISH and specific PNA probes. Of course, a prerequisite for dose assessment in all cases is a dose-effect calibration curve. This work illustrates the various methods used; dose response calibration curves, with 95% confidence limits used to estimate dose uncertainties, have been constructed for conventional metaphase analysis and FISH. We also compare the dose-response curve constructed after scoring of dicentrics and rings using PCC combined with FISH and PNA probes. Also reported are dose response curves showing scored dicentrics and rings per cell, combining

Accidental and retrospective dosimetry using TL method

International Nuclear Information System (INIS)

Mesterházy, D.; Osvay, M.; Kovács, A.; Kelemen, A.

2012-01-01

Retrospective dosimetry is one of the most important tools of accidental dosimetry for dose estimation when dose measurement was not planned. In the affected area many objects can be applied as natural dosimeters. The paper discusses our recent investigations on various electronic components and common salt (NaCl) having useful thermoluminescence (TL) properties. Among materials investigated the electronic components of cell phones seem promising for retrospective dosimetry purposes, having high TL responses, proper glow curve peaks and the intensity of TL peaks vs. gamma dose received provided nearly linear response in the dose range of 10 mGy–1.5 Gy. - Highlights: ► Electronic components and common salt were investigated for accidental and retrospective dosimetry. ► SMD resistors seem promising for retrospective dosimetry purposes. ► Table salt can be used effectively for accidental dosimetry purposes, as well.

Chemical dosimetry system for criticality accidents.

Science.gov (United States)

Miljanić, Saveta; Ilijas, Boris

2004-01-01

Ruder Bosković Institute (RBI) criticality dosimetry system consists of a chemical dosimetry system for measuring the total (neutron + gamma) dose, and a thermoluminescent (TL) dosimetry system for a separate determination of the gamma ray component. The use of the chemical dosemeter solution chlorobenzene-ethanol-trimethylpentane (CET) is based on the radiolytic formation of hydrochloric acid, which protonates a pH indicator, thymolsulphonphthalein. The high molar absorptivity of its red form at 552 nm is responsible for a high sensitivity of the system: doses in the range 0.2-15 Gy can be measured. The dosemeter has been designed as a glass ampoule filled with the CET solution and inserted into a pen-shaped plastic holder. For dose determinations, a newly constructed optoelectronic reader has been used. The RBI team took part in the International Intercomparison of Criticality Accident Dosimetry Systems at the SILENE Reactor, Valduc, June 2002, with the CET dosimetry system. For gamma ray dose determination TLD-700 TL detectors were used. The results obtained with CET dosemeter show very good agreement with the reference values.

Ultraviolet and infrared spectral analysis of poly(vinyl)butyral films: correlation and possible application for high-dose radiation dosimetry

International Nuclear Information System (INIS)

Ebraheem, S.; El-Kelany, M.; Beshir, W.; Abdel-Fattah, A.A.

1999-01-01

A detailed study was performed to develop the dosimetric characteristics of poly(vinyl)butyral film (PVB), to be used as a film dosimeter for high-dose gamma radiation dosimetry. The useful dose range of this polymeric film extends up to 350 kGy. Correlations were established between the absorbed dose of gamma radiation and the radiation-induced changes in PVB measured by means of ultraviolet (UV) and Fourier Transform Infrared (FTIR) spectrophotometry. The results showed a significant dependence of the response on the selected readout tool of measurements whether FTIR (at 1738 and 3400 cm -1 ) or UV (at 275 and 230 nm), as well as on the quantity used for calculation. The effect of relative humidity during irradiation on dosimeter performance as well as the post-irradiation stability at different storage conditions are also discussed. (author)

Commissioning dosimetry and in situ dose mapping of a semi-industrial Cobalt-60 gamma-irradiation facility using Fricke and Ceric-cerous dosimetry system and comparison with Monte Carlo simulation data

Science.gov (United States)

Mortuza, Md Firoz; Lepore, Luigi; Khedkar, Kalpana; Thangam, Saravanan; Nahar, Arifatun; Jamil, Hossen Mohammad; Bandi, Laxminarayan; Alam, Md Khorshed

2018-03-01

Characterization of a 90 kCi (3330 TBq), semi-industrial, cobalt-60 gamma irradiator was performed by commissioning dosimetry and in-situ dose mapping experiments with Ceric-cerous and Fricke dosimetry systems. Commissioning dosimetry was carried out to determine dose distribution pattern of absorbed dose in the irradiation cell and products. To determine maximum and minimum absorbed dose, overdose ratio and dwell time of the tote boxes, homogeneous dummy product (rice husk) with a bulk density of 0.13 g/cm3 were used in the box positions of irradiation chamber. The regions of minimum absorbed dose of the tote boxes were observed in the lower zones of middle plane and maximum absorbed doses were found in the middle position of front plane. Moreover, as a part of dose mapping, dose rates in the wall positions and some selective strategic positions were also measured to carry out multiple irradiation program simultaneously, especially for low dose research irradiation program. In most of the cases, Monte Carlo simulation data, using Monte Carlo N-Particle eXtended code version MCNPX 2.7., were found to be in congruence with experimental values obtained from Ceric-cerous and Fricke dosimetry; however, in close proximity positions from the source, the dose rate variation between chemical dosimetry and MCNP was higher than distant positions.

A microcomputer controlled thermoluminescence dosimetry system

International Nuclear Information System (INIS)

Huyskens, C.J.; Kicken, P.J.H.

1980-01-01

Using a microcomputer, an automatic thermoluminescence dosimetry system for personal dosimetry and thermoluminescence detector (TLD) research was developed. Process automation, statistical computation and dose calculation are provided by this microcomputer. Recording of measurement data, as well as dose record keeping for radiological workers is carried out with floppy disk. The microcomputer also provides a human/system interface by means of a video display and a printer. The main features of this dosimetry system are its low cost, high degree of flexibility, high degree of automation and the feasibility for use in routine dosimetry as well as in TLD research. The system is in use for personal dosimetry, environmental dosimetry and for TL-research work. Because of its modular set-up several components of the system are in use for other applications, too. The system seems suited for medium sized health physics groups. (author)

Dose measurements in dental radiology using thermoluminescent dosimetry

International Nuclear Information System (INIS)

Chiara, Ana Claudia M. de; Costa, Alessandro M.; Pardini, Luiz Carlos

2009-01-01

The aim of this work was the implementation of a code of practice for dosimetry in dental radiology using the technique of thermoluminescent dosimetry. General principles for the use of thermoluminescent dosimeters were followed. The irradiations were performed using ten X-ray equipment for intra-oral radiography and an X-ray equipment for panoramic radiography. The incident air kerma was evaluated for five different exposure times used in clinical practice for intra-oral radiographs. Using a backscatter factor of 1.2, it was observed that approximately 40% of the entrance skin dose values found for intra-oral radiographs are above the diagnostic reference level recommended in national regulation. Different configurations of voltage and current were used representing the exposure as a child, woman and man for panoramic radiographs. The results obtained for the air kerma area product were respectively 53.3 +- 5.2 mGy.cm 2 , 101.5 +- 9.5 mGy.cm 2 and 116.8 +- 10.4 mGy.cm 2 . The use of thermoluminescent dosimetry requires several procedures before a result is recorded. The use of dosimeters with ionization chambers or semiconductors provides a simple and robust method for routine measurements. However, the use of thermoluminescent dosimetry can be of great value to large-scale surveys to establish diagnostic reference levels. (author)

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

International Nuclear Information System (INIS)

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

1999-01-01

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

FTIR spectroscopy as an alternative tool for high gamma dose dosimetry using P(VDF-TrFE) fluorinated copolymers

Energy Technology Data Exchange (ETDEWEB)

Medeiros, Adriana S.; Liz, Otavio S., E-mail: asm@cdtn.b [Universidade Federal de Minas Gerais (DEN/UFMG), Belo Horizonte, MG (Brazil). Dept. de Engenharia Nuclear; Faria, Luiz O., E-mail: farialo@cdtn.b [Centro de Desenvolvimento da Tecnologia Nuclear (CDTN/CNEN-MG), Belo Horizonte, MG (Brazil)

2011-07-01

Poly(vinylidene fluoride) [PVDF] is a semicrystalline homopolymer and some of its fluorinated copolymer has demonstrated to have sensitiveness to high doses of ionizing radiation. We have recently proposed a semicrystalline fluorinated PVDF copolymer, the poly(vinylidene-trifluorethylene) [P(VDF-TrFE], as a candidate for measuring larger dose ranges. In fact, in these copolymers the optical absorption peak at 274 nm has been used to measure gamma doses ranging from 1.0 to 100.0 kGy and the melting latent heat, collected by differential scanning calorimetry (DSC), have been used to measure gamma doses from 1.0 to 1,000.0 kGy. In this paper, the infrared stretching vibration of radio-induced in-chain unsaturations (CH=CF) in P(VDF-TrFE) copolymers has been considered as an alternative tool for high dose dosimetric purposes. FTIR spectroscopic data revealed two optical absorption bands at 1754 cm{sup -1} and 1854 cm{sup -1} whose intensities are unambiguously related to gamma delivered doses ranging from 100.0 kGy to 1,000.0 kGy. Fading was evaluated one month after irradiation. The results indicate that the sample dose evaluation should be performed in the first two hours after being exposed to the radiation beam. The radio-induced formation of unsaturations was also investigated by ultraviolet and visible spectroscopy, which has confirmed the gradual increase of conjugated C=C bonds with the absorbed dose. Our results indicate that quantitative analysis of FTIR absorption bands is a useful tool to perform a product end-point dosimetry in radiation processing facilities that use high gamma dose irradiation. (author)

True dose from incorporated activities. Models for internal dosimetry

International Nuclear Information System (INIS)

Breustedt, B.; Eschner, W.; Nosske, D.

2012-01-01

The assessment of doses after incorporation of radionuclides cannot use direct measurements of the doses, as for example dosimetry in external radiation fields. The only observables are activities in the body or in excretions. Models are used to calculate the doses based on the measured activities. The incorporated activities and the resulting doses can vary by more than seven orders of magnitude between occupational and medical exposures. Nevertheless the models and calculations applied in both cases are similar. Since the models for the different applications have been developed independently by ICRP and MIRD different terminologies have been used. A unified terminology is being developed. (orig.)

OSL signal of IC chips from mobile phones for dose assessment in accidental dosimetry

International Nuclear Information System (INIS)

Mrozik, A.; Marczewska, B.; Bilski, P.; Książek, M.

2017-01-01

The rapid assessment of the radiation dose is very important for the prediction of biological effects after unintended exposition. The materials for use as dosimeters in accidental dosimetry should be everyday objects which are usually placed near the human body, for example mobile phones. IC (Integrated Circuit) chip is one of several electronic components of mobile phones which give a luminescent signal. The measurements of samples from different mobile phones and smartphones were conducted by optically stimulated luminescence (OSL) and thermoluminescence (TL) methods. The OSL measurement was performed in two ways: with readouts at room temperature and at 100 °C. This work is focused on determination of OSL dose response of IC chips, minimum detectable dose (MDD), OSL signal stability in the time after the exposition, its repeatability and sensitivity to light. Several tests of the assessment of unknown doses were also conducted. The readouts at 100 °C indicate the reducing of the fading of OSL signal in the first hours after irradiation in comparison with room temperature readouts. The obtained results showed relatively good dosimetric properties of IC chips: their high sensitivity to the ionizing radiation, linear dose response up to 10 Gy and a good reproducibility of OSL signal which can allow the dose recovery of doses less than 2 Gy in 14 days after an incident with the accuracy better than 25%. The fading is a drawback of IC chips and the fading factor should be considered when calculating the dose. - Highlights: • IC chips from smartphones demonstrated high potential for accidental dosimetry. • Minimum detectable dose was estimated as a value of 50 mGy. • Samples showed linear dose response for the dose range from 0.05 Gy up to 10 Gy.

In vivo dosimetry of high-dose-rate brachytherapy: Study on 61 head-and-neck cancer patients using radiophotoluminescence glass dosimeter

International Nuclear Information System (INIS)

Nose, Takayuki; Koizumi, Masahiko; Yoshida, Ken; Nishiyama, Kinji; Sasaki, Junichi; Ohnishi, Takeshi; Peiffert, Didier

2005-01-01

Purpose: The largest in vivo dosimetry study for interstitial brachytherapy yet examined was performed using new radiophotoluminescence glass dosimeters (RPLGDs). Based on the results, a dose prescription technique achieving high reproducibility and eliminating large hyperdose sleeves was studied. Methods and materials: For 61 head-and-neck cancer patients who underwent high-dose-rate interstitial brachytherapy, new RPLGDs were used for an in vivo study. The Paris System was used for implant. An arbitrary isodose surface was selected for dose prescription. Locations of 83 dosimeters were categorized as on target (n = 52) or on nontarget organ (n = 31) and were also scaled according to % basal dose isodose surface (% BDIS). Compatibility (measured dose/calculated dose) was analyzed according to location. The hyperdose sleeve was assessed in terms of prescription surface expressed in % BDIS. Results: The spread of compatibilities was larger for on nontarget organ (1.06 ± 0.32) than for on target (0.87 ± 0.17, p = 0.01). Within on target RPLGDs, compatibility on 77% and < 95% BDIS for reproducibility and elimination of excessive hyperdose sleeve. For organs at risk, radioprotection should be considered even when calculated dose seems sufficiently low. Further development of planning software is necessary to prevent overestimation

Radiation Parameters of High Dose Rate Iridium -192 Sources

Science.gov (United States)

Podgorsak, Matthew B.

A lack of physical data for high dose rate (HDR) Ir-192 sources has necessitated the use of basic radiation parameters measured with low dose rate (LDR) Ir-192 seeds and ribbons in HDR dosimetry calculations. A rigorous examination of the radiation parameters of several HDR Ir-192 sources has shown that this extension of physical data from LDR to HDR Ir-192 may be inaccurate. Uncertainty in any of the basic radiation parameters used in dosimetry calculations compromises the accuracy of the calculated dose distribution and the subsequent dose delivery. Dose errors of up to 0.3%, 6%, and 2% can result from the use of currently accepted values for the half-life, exposure rate constant, and dose buildup effect, respectively. Since an accuracy of 5% in the delivered dose is essential to prevent severe complications or tumor regrowth, the use of basic physical constants with uncertainties approaching 6% is unacceptable. A systematic evaluation of the pertinent radiation parameters contributes to a reduction in the overall uncertainty in HDR Ir-192 dose delivery. Moreover, the results of the studies described in this thesis contribute significantly to the establishment of standardized numerical values to be used in HDR Ir-192 dosimetry calculations.

TestDose: A nuclear medicine software based on Monte Carlo modeling for generating gamma camera acquisitions and dosimetry

Energy Technology Data Exchange (ETDEWEB)

Garcia, Marie-Paule, E-mail: marie-paule.garcia@univ-brest.fr; Villoing, Daphnée [UMR 1037 INSERM/UPS, CRCT, 133 Route de Narbonne, 31062 Toulouse (France); McKay, Erin [St George Hospital, Gray Street, Kogarah, New South Wales 2217 (Australia); Ferrer, Ludovic [ICO René Gauducheau, Boulevard Jacques Monod, St Herblain 44805 (France); Cremonesi, Marta; Botta, Francesca; Ferrari, Mahila [European Institute of Oncology, Via Ripamonti 435, Milano 20141 (Italy); Bardiès, Manuel [UMR 1037 INSERM/UPS, CRCT, 133 Route de Narbonne, Toulouse 31062 (France)

2015-12-15

Purpose: The TestDose platform was developed to generate scintigraphic imaging protocols and associated dosimetry by Monte Carlo modeling. TestDose is part of a broader project (www.dositest.com) whose aim is to identify the biases induced by different clinical dosimetry protocols. Methods: The TestDose software allows handling the whole pipeline from virtual patient generation to resulting planar and SPECT images and dosimetry calculations. The originality of their approach relies on the implementation of functional segmentation for the anthropomorphic model representing a virtual patient. Two anthropomorphic models are currently available: 4D XCAT and ICRP 110. A pharmacokinetic model describes the biodistribution of a given radiopharmaceutical in each defined compartment at various time-points. The Monte Carlo simulation toolkit GATE offers the possibility to accurately simulate scintigraphic images and absorbed doses in volumes of interest. The TestDose platform relies on GATE to reproduce precisely any imaging protocol and to provide reference dosimetry. For image generation, TestDose stores user’s imaging requirements and generates automatically command files used as input for GATE. Each compartment is simulated only once and the resulting output is weighted using pharmacokinetic data. Resulting compartment projections are aggregated to obtain the final image. For dosimetry computation, emission data are stored in the platform database and relevant GATE input files are generated for the virtual patient model and associated pharmacokinetics. Results: Two samples of software runs are given to demonstrate the potential of TestDose. A clinical imaging protocol for the Octreoscan™ therapeutical treatment was implemented using the 4D XCAT model. Whole-body “step and shoot” acquisitions at different times postinjection and one SPECT acquisition were generated within reasonable computation times. Based on the same Octreoscan™ kinetics, a dosimetry

A high dose dosimeter based polyvinyl chloride dyed with malachite green

International Nuclear Information System (INIS)

Kattan, M.; Daher, Y.; Alkassiri, H.

2007-01-01

Polyvinyl chloride film (PVC) dyed with malachite green has been studied for high dose radiation dosimetry using visible spectrophotometry. A linear relationship between the relative absorbance and the absorbed dose at the wavelength 628 nm in the range of 0-125 kGy was found. The effect of dose rate, irradiation temperature, film thickness and dye intensity were found not to influence the response. The effects of shelf-life and the post-irradiation storage in darkness and indirect daylight conditions on dosimetry performance were discussed. (author)

Evaluating the Application of Tissue-Specific Dose Kernels Instead of Water Dose Kernels in Internal Dosimetry : A Monte Carlo Study

NARCIS (Netherlands)

Moghadam, Maryam Khazaee; Asl, Alireza Kamali; Geramifar, Parham; Zaidi, Habib

2016-01-01

Purpose: The aim of this work is to evaluate the application of tissue-specific dose kernels instead of water dose kernels to improve the accuracy of patient-specific dosimetry by taking tissue heterogeneities into consideration. Materials and Methods: Tissue-specific dose point kernels (DPKs) and

Developments in physical dosimetry and radiation protection; Entwicklungen in der physikalischen Dosimetrie im Strahlenschutz

Energy Technology Data Exchange (ETDEWEB)

Fiebich, Martin [Technische Hochschule Mittelhessen, Giessen (Germany). Inst. fuer Medizinische Physik und Strahlenschutz

2017-07-01

In the frame of physical dosimetry new dose units have been defined: the depth personal dose (equivalent dose in 10 mm depth) and the surface personal dose (equivalent dose in 0.07 mm depth). Physical dosimetry is applied for the determination of occupational radiation exposure, the radiation protected area control, the estimation of radiation exposure of patients during radiotherapy, for quality assurance and in research projects and optimization challenges. Developments have appeared with respect to punctual measuring chambers, eye lens dosimetry, OSL (optically stimulated luminescence) dosimetry, real-time dosimetry and Monte Carlo methods. New detection limits of about 1 micro Gy were reached.

Conventional and CT angiography in children: dosimetry and dose comparisons

International Nuclear Information System (INIS)

Frush, Donald P.; Yoshizumi, Terry

2006-01-01

Tremendous advances have been made in imaging in children with both congenital and acquired heart disease. These include technical advances in cardiac catheterization and conventional angiography, especially with advancements in interventional procedures, as well as noninvasive imaging with MR and CT angiography. With rapid advances in multidetector CT (MDCT) technology, most recently 64-detector array systems (64-slice MDCT), have come a number of advantages over MR. However, both conventional and CT angiography impart radiation dose to children. Although the presence of radiation exposure to children has long been recognized, it is apparent that our ability to assess this dose, particularly in light of the rapid advancements, has been limited. Traditional methods of dosimetry for both conventional and CT angiography are somewhat cumbersome or involve a potential for substantial uncertainty. Recent developments in dosimetry, including metal oxide semiconductor field effect transistors (MOSFET) and the availability of anthropomorphic, tissue-equivalent phantoms have provided new opportunities for dosimetric assessments. Recent work with this technology in state-of-the-art cardiac angiography suites as well as with MDCT have offered direct comparisons of doses in infants and children undergoing diagnostic cardiac evaluation. It is with these dose data that assessment of risks, and ultimately the assessment of risk-benefit, can be better achieved. (orig.)

Conductivity of alanine solution for high level dosimetry

International Nuclear Information System (INIS)

Wieser, A.; Figel, M.; Regulla, D.F.

1993-01-01

The amino acid alanine is well known as a dosimetric detector material for high level dosimetry. Its application is based on the formation of radicals by ionising radiation. The free radicals are earlier detected by electron spin resonance (ESR) spectroscopy or chemically after dissolving the irradiated samples. Of all these methods the ESR/alanine system is the most advanced and is suggested for reference dosimetry. At present, however, the high cost of the system is a serious handicap for a large scale routine application in radiation plants. In this study the variation of electrical conductivity of L-alanine solution with applied dose is investigated in the range from 0.5-200 kGy. The conductivity was measured with a 50 MHz RF oscillator. This readout method is uncomplicated and may be suitable for routine application. The experiments were performed with L-alanine solution in glass ampoules. (Author)

Radiotherapy Dosimetry Protocols For High Energy Photons And Electrons

International Nuclear Information System (INIS)

Thwaites, D.I.

1999-01-01

One vital requirement in radiotherapy is to ensure as closely as possible consistency in determination of dose between different centers and at different times, both within a given country and internationally, because the comparison and transfer of clinical experience and the evaluation of clinical trials is dependent on common statements of dose delivered. In addition at each loon] centre it is vital that the absorbed dose calibration of each beam is carried out to exacting and consistent standards, as this is the fundamental measurement upon which the quality of all treatments on that machine depend throughout its clinical lifetime. The systems in place to ensure consistency in dosimetry differ in the details from country to country, but all depend on the same basic considerations: - the use of ion chambers of similar design and similar construction materials, - traceable calibrations of these chambers to an accredited primary or secondary standard dosimetry laboratory (SSDL) in terms of some agreed relevant dosimetric quantity, - dose statements in terms of absorbed dose to a common material, water, - the application of an appropriate recommended national or international dosimetry protocol (or code of practice) which ensures commonality in the method of use of the calibrated ion chamber, the radiotherapy treatment beam calibration conditions and any data required to convert the ion chamber reading to absorbed dose to water, and - strict quality control on each step in this process

Dose measurement techniques for high-energy photon and electron radiation

International Nuclear Information System (INIS)

Hohlfeld, K.; Roos, M.

1992-08-01

By law the Federal Institute of Physics and Technology (PTB) has been assigned the tasks of representing, preserving and passing on dose units. The analogous continuation of these tasks consists in improving, at the user level, dosimetry techniques in radiation therapy for the benefit of patients. The PTB had an essential share in working out the scientific foundations of dosimetry for high-energy radiation, and the corresponding DIN standards were established with the PTB playing a prominent part. The seminar aimed at presenting the measuring techniques fixed in the new DIN standard 6800 part 2 'Dose measurement techniques according to the probe method - ionization dosimetry', to discuss their physical background and practical implications resulting from them. (orig.) [de

Development of dosimeters with rad-hard silicon diodes for high dose dosimetry

International Nuclear Information System (INIS)

Camargo, Fabio de

2009-01-01

In this work we report on results obtained with rad-hard Standard Float Zone (FZ), Diffusion Oxygenated Float Zone (DOFZ) and Magnetic Czochralski (MCz) silicon diodes in gamma radiation processing dosimetry. These p ± n-n + junction devices were manufactured by Okmetic Oyj. (Vantaa, Finland) and processed by the Microelectronics Center of Helsinki University of Technology in the framework of the CERN RD50 Collaboration. The dosimetric probes, based on FZ, DOFZ and M Cz devices, were designed to operate without bias voltage in the direct current mode as on-line radiation dosimeter. The irradiations were performed in the Radiation Technology Center (CTR) at IPEN-CNEN/SP using a 60 Co source (Gamma cell 220 - Nordion) with a dose rate around of 2.4 kGy/h. The current response of each diode was measured as a function of the exposure time in steps from 5 kGy up to 50 kGy to achieve a total absorbed dose of 275 kGy. The results obtained showed a significant decrease in the photocurrent generated in all devices for total absorbed doses higher than approximately 25 kGy. To reduce this effect, the samples were pre-irradiated with 60 Co gamma rays at 700 kGy in order to saturate the trap production in the diode's sensitive volume. After pre-irradiation, despite of being less sensitive, all devices exhibited more stable photocurrent signals, even for total absorbed doses of 275 kGy. To monitor possible gamma radiation damage effects produced on the diodes, their dynamic leakage current and capacitance were measured as a function of the absorbed dose. (author)

Internal sources dosimetry

International Nuclear Information System (INIS)

Savio, Eduardo

1994-01-01

The absorbed dose, need of estimation in risk evaluation in the application of radiopharmaceuticals in Nuclear Medicine practice,internal dosimetry,internal and external sources. Calculation methodology,Marinelli model,MIRD system for absorbed dose calculation based on biological parameters of radiopharmaceutical in human body or individual,energy of emitted radiations by administered radionuclide, fraction of emitted energy that is absorbed by target body.Limitation of the MIRD calculation model. A explanation of Marinelli method of dosimetry calculation,β dosimetry. Y dosimetry, effective dose, calculation in organs and tissues, examples. Bibliography .

EPR Dosimetry - Present and Future

Energy Technology Data Exchange (ETDEWEB)

Regulla, D.F. [GSF - National Research Centre for Environment and Health, Institute of Radiation Protection, 85764 Neuherberg (Germany)

1999-07-01

In the past, IAEA has played a central role in stipulating research and development in EPR high-dose standardisation as well as in coordinating and organising international dose intercomparison programs, within the Member States of the United Nations from the mid-seventies till today. The future tasks of EPR dosimetry seem to tend towards different subjects such as bio markers, biological radiation effects, post-accident dose reconstruction in the environment, and retrospective human dosimetry. The latter may be considered a promising tool for epidemiology on the way to re-define radiation risk of man for chronicle radiation exposures, based on e.g. South Ural civil population and radiation workers. There are on-going international activities in the field of standardising high-level dosimetry by the American Standards on Testing and Materials (Astm), and by the International Organisation of Standards (ISO). The International Commission on Radiation Units and Measurements (ICRU) is considering the establishment of relevant recommendations concerning industrial radiation processing, but also human dose reconstruction. (Author)

EPR Dosimetry - Present and Future

International Nuclear Information System (INIS)

Regulla, D.F.

1999-01-01

In the past, IAEA has played a central role in stipulating research and development in EPR high-dose standardisation as well as in coordinating and organising international dose intercomparison programs, within the Member States of the United Nations from the mid-seventies till today. The future tasks of EPR dosimetry seem to tend towards different subjects such as bio markers, biological radiation effects, post-accident dose reconstruction in the environment, and retrospective human dosimetry. The latter may be considered a promising tool for epidemiology on the way to re-define radiation risk of man for chronicle radiation exposures, based on e.g. South Ural civil population and radiation workers. There are on-going international activities in the field of standardising high-level dosimetry by the American Standards on Testing and Materials (Astm), and by the International Organisation of Standards (ISO). The International Commission on Radiation Units and Measurements (ICRU) is considering the establishment of relevant recommendations concerning industrial radiation processing, but also human dose reconstruction. (Author)

Topics in radiation dosimetry radiation dosimetry

CERN Document Server

1972-01-01

Radiation Dosimetry, Supplement 1: Topics in Radiation Dosimetry covers instruments and techniques in dealing with special dosimetry problems. The book discusses thermoluminescence dosimetry in archeological dating; dosimetric applications of track etching; vacuum chambers of radiation measurement. The text also describes wall-less detectors in microdosimetry; dosimetry of low-energy X-rays; and the theory and general applicability of the gamma-ray theory of track effects to various systems. Dose equivalent determinations in neutron fields by means of moderator techniques; as well as developm

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)

Specific gamma-ray dose constants for nuclides important to dosimetry and radiological assessment

International Nuclear Information System (INIS)

Unger, L.M.; Trubey, D.K.

1982-05-01

Tables of specific gamma-ray dose constants (the unshielded gamma-ray dose equivalent rate at 1 m from a point source) have been computed for approximately 500 nuclides important to dosimetry and radiological assessment. The half life, the mean attenuation coefficient, and thickness for a lead shield providing 95% dose equivalent attenuation are also listed

Thermoluminescence kinetics in materials exposed to the low doses applicable to dating and dosimetry

International Nuclear Information System (INIS)

Levy, P.W.

1984-11-01

Thermoluminescence (TL) kinetics have been investigated for low dose situations applicable to dating, dosimetry, and recent geological deposits. Studied were the general one-trap kinetic equation, which reduces to the well known 1st and 2nd order kinetic equations when various assumptions apply, and the interactive kinetic equations, which describes TL in materials exhibiting more than one glow peak. In materials with one glow peak area varies linearly with dose; however, peak height is not linear with dose unless the TL obeys 1st order kinetics at all doses. In materials with two or more glow peaks neither peak height nor peak area varies linearly with dose, except in special situations. In fact, many peak height vs dose curves will be supralinear with the initial low-slope region occurring at relatively low doses. These considerations indicate: (1) Dating and dosimetry technique based on assumed linear peak height vs dose curves will usually underestimate the accumulated dose. (2) Dating techniques can be improved and/or made more reliable by determining the TL kinetics of the glow peaks measured

OEDIPE, a software for personalized Monte Carlo dosimetry and treatment planning optimization in nuclear medicine: absorbed dose and biologically effective dose considerations

International Nuclear Information System (INIS)

Petitguillaume, A.; Broggio, D.; Franck, D.; Desbree, A.; Bernardini, M.; Labriolle Vaylet, C. de

2014-01-01

For targeted radionuclide therapies, treatment planning usually consists of the administration of standard activities without accounting for the patient-specific activity distribution, pharmacokinetics and dosimetry to organs at risk. The OEDIPE software is a user-friendly interface which has an automation level suitable for performing personalized Monte Carlo 3D dosimetry for diagnostic and therapeutic radionuclide administrations. Mean absorbed doses to regions of interest (ROIs), isodose curves superimposed on a personalized anatomical model of the patient and dose-volume histograms can be extracted from the absorbed dose 3D distribution. Moreover, to account for the differences in radiosensitivity between tumoral and healthy tissues, additional functionalities have been implemented to calculate the 3D distribution of the biologically effective dose (BED), mean BEDs to ROIs, isoBED curves and BED-volume histograms along with the Equivalent Uniform Biologically Effective Dose (EUD) to ROIs. Finally, optimization tools are available for treatment planning optimization using either the absorbed dose or BED distributions. These tools enable one to calculate the maximal injectable activity which meets tolerance criteria to organs at risk for a chosen fractionation protocol. This paper describes the functionalities available in the latest version of the OEDIPE software to perform personalized Monte Carlo dosimetry and treatment planning optimization in targeted radionuclide therapies. (authors)

Dosimetry of Al2O3 optically stimulated luminescent dosimeter at high energy photons and electrons

Science.gov (United States)

Yusof, M. F. Mohd; Joohari, N. A.; Abdullah, R.; Shukor, N. S. Abd; Kadir, A. B. Abd; Isa, N. Mohd

2018-01-01

The linearity of Al2O3 OSL dosimeters (OSLD) were evaluated for dosimetry works in clinical photons and electrons. The measurements were made at a reference depth of Zref according to IAEA TRS 398:2000 codes of practice at 6 and 10 MV photons and 6 and 9 MeV electrons. The measured dose was compared to the thermoluminescence dosimeters (TLD) and ionization chamber commonly used for dosimetry works for higher energy photons and electrons. The results showed that the measured dose in OSL dosimeters were in good agreement with the reported by the ionization chamber in both high energy photons and electrons. A reproducibility test also reported excellent consistency of readings with the OSL at similar energy levels. The overall results confirmed the suitability of OSL dosimeters for dosimetry works involving high energy photons and electrons in radiotherapy.

High-dose "1"3"1I-MIBG therapies in children: feasibility, patient dosimetry and radiation exposure to workers and family caregivers

International Nuclear Information System (INIS)

Cougnenc, Olivier; Defachelles, Anne-Sophie; Lervat, Cyril; Carpentier, Philippe; Oudoux, Aurore; Kolesnikov-Gauthier, Helene; Clisant, Stephanie

2017-01-01

The objective of the present multi-centric phase II study (MIITOP) was to determine the response rate, survival and toxicity of tandem infusions of "1"3"1I-meta-iodobenzylguanidine (mIBG) and topotecan in children with relapsed/refractory neuroblastoma. High-dose "1"3"1I-mIBG therapy programme requires a deal of planning, availability of hospital resources and the commitment of individuals with training and expertise in multiple disciplines. Here in the present study, procedures and the results of patient's dosimetry, as well as family and worker's exposures, were reported for the patients treated in Lille. A total of 15 children were treated with "1"3"1I-mIBG between 2009 and 2011 according to the MIITOP protocol. High activity of "1"3"1I-mIBG (444 MBq kg"-"1) was administered on Day 0. In vivo dosimetry was used to calculate a second activity, to be given on Day 21, to obtain a total whole body absorbed dose of 4 Gy. Family and worker's exposures were performed too. The injected activity by treatment was from 703 to 11470 MBq. Total whole body absorbed dose by patient ranged from 2.74 to 5.2 Gy. Concerning relatives, whole body exposure ranged from 0.018 to 2.8 mSv. The mean whole body exposure of the radio-pharmacist was 4.4 nSv MBq"-"1, and the mean exposure of fingers ranged from 0.18 to 0.24 μSv MBq"-"1 according to each finger. The mean whole body exposure was 33.6 and 20.2 μSv d"-"1 per person, for night nurses and day nurses, respectively. Exposure of doctors was less than 5 μSv d"-"1. Under strict radiation protection precautions, this study shows the feasibility of high-activity "1"3"1I-mIBG therapy in France. (authors)

Fast, high-resolution 3D dosimetry utilizing a novel optical-CT scanner incorporating tertiary telecentric collimation

International Nuclear Information System (INIS)

Sakhalkar, H. S.; Oldham, M.

2008-01-01

This study introduces a charge coupled device (CCD) area detector based optical-computed tomography (optical-CT) scanner for comprehensive verification of radiation dose distributions recorded in nonscattering radiochromic dosimeters. Defining characteristics include: (i) a very fast scanning time of ∼5 min to acquire a complete three-dimensional (3D) dataset, (ii) improved image formation through the use of custom telecentric optics, which ensures accurate projection images and minimizes artifacts from scattered and stray-light sources, and (iii) high resolution (potentially 50 μm) isotropic 3D dose readout. The performance of the CCD scanner for 3D dose readout was evaluated by comparison with independent 3D readout from the single laser beam OCTOPUS-scanner for the same PRESAGE dosimeters. The OCTOPUS scanner was considered the 'gold standard' technique in light of prior studies demonstrating its accuracy. Additional comparisons were made against calculated dose distributions from the ECLIPSE treatment-planning system. Dose readout for the following treatments were investigated: (i) a single rectangular beam irradiation to investigate small field and very steep dose gradient dosimetry away from edge effects, (ii) a 2-field open beam parallel-opposed irradiation to investigate dosimetry along steep dose gradients, and (iii) a 7-field intensity modulated radiation therapy (IMRT) irradiation to investigate dosimetry for complex treatment delivery involving modulation of fluence and for dosimetry along moderate dose gradients. Dose profiles, dose-difference plots, and gamma maps were employed to evaluate quantitative estimates of agreement between independently measured and calculated dose distributions. Results indicated that dose readout from the CCD scanner was in agreement with independent gold-standard readout from the OCTOPUS-scanner as well as the calculated ECLIPSE dose distribution for all treatments, except in regions within a few millimeters of the

Film dosimetry using a smart device camera: a feasibility study for point dose measurements

Science.gov (United States)

Aland, Trent; Jhala, Ekta; Kairn, Tanya; Trapp, Jamie

2017-10-01

In this work, a methodology for using a smartphone camera, in conjunction with a light-tight box operating in reflective transmission mode, is investigated as a proof of concept for use as a film dosimetry system. An imaging system was designed to allow the camera of a smartphone to be used as a pseudo densitometer. Ten pieces of Gafchromic EBT3 film were irradiated to doses up to 16.89 Gy and used to evaluate the effects of reproducibility and orientation, as well as the ability to create an accurate dose response curve for the smartphone based dosimetry system, using all three colour channels. Results were compared to a flatbed scanner system. Overall uncertainty was found to be best for the red channel with an uncertainty of 2.4% identified for film irradiated to 2.5 Gy and digitised using the smartphone system. This proof of concept exercise showed that although uncertainties still exceed a flatbed scanner system, the smartphone system may be useful for providing point dose measurements in situations where conventional flatbed scanners (or other dosimetry systems) are unavailable or unaffordable.

Film dosimetry using a smart device camera: a feasibility study for point dose measurements.

Science.gov (United States)

Aland, Trent; Jhala, Ekta; Kairn, Tanya; Trapp, Jamie

2017-10-03

In this work, a methodology for using a smartphone camera, in conjunction with a light-tight box operating in reflective transmission mode, is investigated as a proof of concept for use as a film dosimetry system. An imaging system was designed to allow the camera of a smartphone to be used as a pseudo densitometer. Ten pieces of Gafchromic EBT3 film were irradiated to doses up to 16.89 Gy and used to evaluate the effects of reproducibility and orientation, as well as the ability to create an accurate dose response curve for the smartphone based dosimetry system, using all three colour channels. Results were compared to a flatbed scanner system. Overall uncertainty was found to be best for the red channel with an uncertainty of 2.4% identified for film irradiated to 2.5 Gy and digitised using the smartphone system. This proof of concept exercise showed that although uncertainties still exceed a flatbed scanner system, the smartphone system may be useful for providing point dose measurements in situations where conventional flatbed scanners (or other dosimetry systems) are unavailable or unaffordable.

An on-site dosimetry audit for high-energy electron beams

Directory of Open Access Journals (Sweden)

Leon de Prez

2018-01-01

Full Text Available Background and purpose: External dosimetry audits are powerful quality assurance instruments for radiotherapy. The aim of this study was to implement an electron dosimetry audit based on a contemporary code of practice within the requirements for calibration laboratories performing proficiency tests. This involved the determination of suitable acceptance criteria based on thorough uncertainty analyses. Materials and methods: Subject of the audit was the determination of absorbed dose to water, Dw, and the beam quality specifier, R50,dos. Fifteen electron beams were measured in four institutes according to the Belgian-Dutch code of practice for high-energy electron beams. The expanded uncertainty (k = 2 for the Dw values was 3.6% for a Roos chamber calibrated in 60Co and 3.2% for a Roos chamber cross-calibrated against a Farmer chamber. The expanded uncertainty for the beam quality specifier, R50,dos, was 0.14 cm. The audit acceptance levels were based on the expanded uncertainties for the comparison results and estimated to be 2.4%. Results: The audit was implemented and validated successfully. All Dw audit results were satisfactory with differences in Dw values mostly smaller than 0.5% and always smaller than 1%. Except for one, differences in R50,dos were smaller than 0.2 cm and always smaller than 0.3 cm. Conclusions: An electron dosimetry audit based on absorbed dose to water and present-day requirements for calibration laboratories performing proficiency tests was successfully implemented. It proved international traceability of the participants value with an uncertainty better than 3.6% (k = 2. Keywords: Absorbed dose to water, Audit, Code of practice, Dosimetry, Electron beam, Radiation therapy

Monte Carlo validation and optimisation of detector packaging for spectroscopic dosimetry for in vivo urethral dosimetry during low dose rate brachytherapy

International Nuclear Information System (INIS)

Nourbehesht, L.K.; Cutajar, D.L.; Guatelli, S.; Rosenfeld, A.B.

2015-01-01

The urethral mini-dosimeter, developed by the Centre for Medical Radiation Physics, University of Wollongong, uses spectroscopic dosimetry to provide real time point dose measurements along the urethra during low dose rate prostate brachytherapy. Spectroscopic dosimetry uses the measured spectrum of the treatment isotope to estimate the dose rate at the point of measurement, however, the silicon mini-detectors employed in the urethral mini-dosimeter require water proof encapsulation which must be capable of providing electromagnetic shielding without greatly increasing the size of the probe. The introduction of non-tissue equivalent materials within the encapsulation can change the spectrum of radiation incident on the detector, which may influence the application of spectroscopic dosimetry within the urethral dosimeter. The Monte Carlo code Geant4 was adopted to study the effect of encapsulation on the operation of the urethral mini-dosimeter, as well as to determine whether an appropriate thickness of aluminium shielding was possible for electromagnetic screening. The depth dose response and angular dependence of the urethral mini-dosimeter with three thicknesses of aluminium shielding (20, 50, 100 µm) was compared with the urethral mini-dosimeter without aluminium shielding. The aluminium shielding had the effect of increasing the depth dose response (up to 3 % within 30 mm and up to 5 % within 50 mm), slightly reduced the azimuth angular dependence and slightly increased the polar angular dependence. The 100 µm thick shielding provided the least azimuth angular dependence (±2 %) and provided a polar angular dependence of ±1.4 % within the angles of −45° to 45°.

Non-conventional personal dosimetry techniques

International Nuclear Information System (INIS)

Regulla, D.F.

1984-01-01

Established dosimetry has achieved a high standard in personnel monitoring. This applies particularly to photon dosimetry. Nevertheless, even in photon dosimetry, improvements and changes are being made. The reason may be technological progress, or the introduction of new tasks on the basis of the recommendations of international bodies (e.g. the new ICRU measurement unit) of national legislation. Since we are restricting ourselves here to technical trends the author would like to draw attention to various activities of current interest, e.g. the computation of receptor-related conversion coefficients from personal dose to organ or body doses, taking into account the conditions of exposure with respect to differential energy and angular distribution of the radiation field. Realistic data on exposure geometry are taken from work place analyses. Furthermore, the data banks of central personal dosimetry services are subject to statistical evaluation and radiation protection trend analysis. Technological progress and developments are considered from the point of view of personal dosimetry, partial body or extremity dosimetry and accidental dosimetry

Overview of double dosimetry procedures for the determination of the effective dose to the interventional radiology staff

International Nuclear Information System (INIS)

Jaervinen, H.; Buls, N.; Clerinx, P.; Jansen, J.; Miljanic, S.; Nikodemova, D.; Ranogajec-Komor, M.; D'Errico, F.

2008-01-01

In interventional radiology, for an accurate determination of effective dose to the staff, measurements with two dosemeters have been recommended, one located above and one under the protective apron. Such 'double dosimetry' practices and the algorithms used for the determination of effective dose were reviewed in this study by circulating a questionnaire and by an extensive literature search. The results indicated that regulations for double dosimetry almost do not exist and there is no firm consensus on the most suitable calculation algorithms. The calculation of effective dose is mainly based on the single dosemeter measurements, in which either personal dose equivalent, directly, (dosemeter below the apron) or a fraction of personal dose equivalent (dosemeter above the apron) is taken as an assessment of effective dose. The most recent studies suggest that there might not be just one double dosimetry algorithm that would be optimum for all interventional radiology procedures. Further investigations in several critical configurations of interventional radiology procedures are needed to assess the suitability of the proposed algorithms. (authors)

Dosimetry

International Nuclear Information System (INIS)

Anon.

1990-01-01

The purpose of ionizing radiation dosimetry is the measurement of the physical and biological consequences of exposure to radiation. As these consequences are proportional to the local absorption of energy, the dosimetry of ionizing radiation is based on the measurement of this quantity. Owing to the size of the effects of ionizing radiation on materials in all of these area, dosimetry plays an essential role in the prevention and the control of radiation exposure. Its use is of great importance in two areas in particular where the employment of ionizing radiation relates to human health: radiation protection, and medical applications. Dosimetry is different for various reasons: owing to the diversity of the physical characteristics produced by different kinds of radiation according to their nature (X- and γ-photons, electrons, neutrons,...), their energy (from several keV to several MeV), the orders of magnitude of the doses being estimated (a factor of about 10 5 between diagnostic and therapeutic applications); and the temporal and spatial variation of the biological parameters entering into the calculations. On the practical level, dosimetry poses two distinct yet closely related problems: the determination of the absorbed dose received by a subject exposed to radiation from a source external to his body (external dosimetry); and the determination of the absorbed dose received by a subject owing to the presence within his body of some radioactive substance (internal dosimetry)

Biological dosimetry: chromosomal aberration analysis for dose assessment

International Nuclear Information System (INIS)

1986-01-01

In view of the growing importance of chromosomal aberration analysis as a biological dosimeter, the present report provides a concise summary of the scientific background of the subject and a comprehensive source of information at the technical level. After a review of the basic principles of radiation dosimetry and radiation biology basic information on the biology of lymphocytes, the structure of chromosomes and the classification of chromosomal aberrations are presented. This is followed by a presentation of techniques for collecting blood, storing, transporting, culturing, making chromosomal preparations and scaring of aberrations. The physical and statistical parameters involved in dose assessment are discussed and examples of actual dose assessments taken from the scientific literature are given

High-accuracy dosimetry study for intensity-modulated radiation therapy(IMRT) commissioning

International Nuclear Information System (INIS)

Jeong, Hae Sun

2010-02-01

Intensity-modulated radiation therapy (IMRT), an advanced modality of high-precision radiotherapy, allows for an increase in dose to the tumor volume without increasing the dose to nearby critical organs. In order to successfully achieve the treatment, intensive dosimetry with accurate dose verification is necessary. A dosimetry for IMRT, however, is a challenging task due to dosimetric ally unfavorable phenomena such as dramatic changes of the dose at the field boundaries, dis-equilibrium of the electrons, non-uniformity between the detector and the phantom materials, and distortion of scanner-read doses. In the present study, therefore, the LEGO-type multi-purpose dosimetry phantom was developed and used for the studies on dose measurements and correction. Phantom materials for muscle, fat, bone, and lung tissue were selected after considering mass density, atomic composition, effective atomic number, and photon interaction coefficients. The phantom also includes dosimeter holders for several different types of detectors including films, which accommodates a construction of different designs of phantoms as necessary. In order to evaluate its performance, the developed phantom was tested by measuring the point dose and the percent depth dose (PDD) for small size fields under several heterogeneous conditions. However, the measurements with the two types of dosimeter did not agree well for the field sizes less than 1 x 1 cm 2 in muscle and bone, and less than 3 x 3 cm 2 in air cavity. Thus, it was recognized that several studies on small fields dosimetry and correction methods for the calculation with a PMCEPT code are needed. The under-estimated values from the ion chamber were corrected with a convolution method employed to eliminate the volume effect of the chamber. As a result, the discrepancies between the EBT film and the ion chamber measurements were significantly decreased, from 14% to 1% (1 x 1 cm 2 ), 10% to 1% (0.7 x 0.7 cm 2 ), and 42% to 7% (0.5 x 0

Development of new methodology for dose calculation in photographic dosimetry

International Nuclear Information System (INIS)

Daltro, T.F.L.; Campos, L.L.; Perez, H.E.B.

1996-01-01

The personal dosemeter system of IPEN is based on film dosimetry. Personal doses at IPEN are mainly due to X or gamma radiation. The use of personal photographic dosemeters involves two steps: firstly, data acquisition including their evaluation with respect to the calibration quantity and secondly, the interpretation of the data in terms of effective dose. The effective dose was calculated using artificial intelligence techniques by means of neural network. The learning of the neural network was performed by taking the readings of optical density as a function of incident energy and exposure from the calibration curve. The obtained output in the daily grind is the mean effective energy and the effective dose. (author)

Dose distribution and dosimetry parameters calculation of MED3633 Palladium-103 source in water phantom using MCNP

International Nuclear Information System (INIS)

Mowlavi, A. A.; Binesh, A.; Moslehitabar, H.

2006-01-01

Palladium-103 ( 103 Pd) is a brachytherapy source for cancer treatment. The Monte Carlo codes are usually applied for dose distribution and effect of shieldings. Monte Carlo calculation of dose distribution in water phantom due to a MED3633 103 Pd source is presented in this work. Materials and Methods: The dose distribution around the 10 3Pd Model MED3633 located in the center of 30*30*30 m 3 water phantom cube was calculated using MCNP code by the Monte Carlo method. The percentage depth dose variation along the different axis parallel and perpendicular to the source was also calculated. Then, the isodose curves for 100%, 75%, 50% and 25% percentage depth dose and dosimetry parameters of TG-43 protocol were determined. Results: The results show that the Monte Carlo Method could calculate dose deposition in high gradient region, near the source, accurately. The isodose curves and dosimetric characteristics obtained for MED3633 103 Pd source are in good agreement with published results. Conclusion: The isodose curves of the MED3633 103 Pd source have been derived form dose calculation by MCNP code. The calculated dosimetry parameters for the source agree quite well with their Monte Carlo calculated and experimental measurement values

Using the OSL single-aliquot regenerative-dose protocol with quartz extracted from building materials in retrospective dosimetry

International Nuclear Information System (INIS)

Boetter-Jensen, L.; Solongo, S.; Murray, A.S.; Banerjee, D.; Jungner, H.

2000-01-01

We report on the application of the single-aliquot regenerative-dose (SAR) protocol to the optically stimulated luminescence signal from quartz extracted from fired bricks and unfired mortar in retrospective dosimetry. The samples came from a radioactive materials storage facility, with ambient dose rates of about 0.1 mGy/h. A detailed dose-depth profile was analysed from one brick, and compared with dose records from area TL dosemeters. Small-aliquot dose-distributions were analysed from the mortar samples; one associated with the exposed brick, and one from a remote site exposed only to background radiation. We conclude that unfired materials have considerable potential in retrospective dosimetry

Personal dosimetry statistics and specifics of low dose evaluation

International Nuclear Information System (INIS)

Avila, R.E.; Gómez Salinas, R.A.; Oyarzún Cortés, C.H.

2015-01-01

The dose statistics of a personal dosimetry service, considering 35,000+ readings, display a sharp peak at low dose (below 0.5 mSv) with skewness to higher values. A measure of the dispersion is that approximately 65% of the doses fall below the average plus 2 standard deviations, an observation which may prove helpful to radiation protection agencies. Categorizing the doses by the concomitant use of a finger ring dosimeter, that skewness is larger in the whole body, and ring dosimeters. The use of Harshaw 5500 readers at high gain leads to frequent values of the glow curve that are judged to be spurious, i.e. values not belonging to the roughly normal noise over the curve. A statistical criterion is shown for identifying those anomalous values, and replacing them with the local behavior, as fit by a cubic polynomial. As a result, the doses above 0.05 mSv which are affected by more than 2% comprise over 10% of the data base. The low dose peak of the statistics, above, has focused our attention on the evaluation of LiF(Mg,Ti) dosimeters exposed at low dose, and read with Harshaw 5500 readers. The standard linear procedure, via an overall reader calibration factor, is observed to fail at low dose, in detailed calibrations from 0.02 mSv to 1 Sv. A significant improvement is achieved by a piecewise polynomials calibration curve. A cubic, at low dose is matched, at ∼10 mSv, in value and first derivative, to a linear dependence at higher doses. This improvement is particularly noticeable below 2 mSv, where over 60% of the evaluated dosimeters are found. (author)

MO-B-BRB-00: Three Dimensional Dosimetry

Energy Technology Data Exchange (ETDEWEB)

NONE

2016-06-15

Full three-dimensional (3D) dosimetry using volumetric chemical dosimeters probed by 3D imaging systems has long been a promising technique for the radiation therapy clinic, since it provides a unique methodology for dose measurements in the volume irradiated using complex conformal delivery techniques such as IMRT and VMAT. To date true 3D dosimetry is still not widely practiced in the community; it has been confined to centres of specialized expertise especially for quality assurance or commissioning roles where other dosimetry techniques are difficult to implement. The potential for improved clinical applicability has been advanced considerably in the last decade by the development of improved 3D dosimeters (e.g., radiochromic plastics, radiochromic gel dosimeters and normoxic polymer gel systems) and by improved readout protocols using optical computed tomography or magnetic resonance imaging. In this session, established users of some current 3D chemical dosimeters will briefly review the current status of 3D dosimetry, describe several dosimeters and their appropriate imaging for dose readout, present workflow procedures required for good dosimetry, and analyze some limitations for applications in select settings. We will review the application of 3D dosimetry to various clinical situations describing how 3D approaches can complement other dose delivery validation approaches already available in the clinic. The applications presented will be selected to inform attendees of the unique features provided by full 3D techniques. Learning Objectives: L. John Schreiner: Background and Motivation Understand recent developments enabling clinically practical 3D dosimetry, Appreciate 3D dosimetry workflow and dosimetry procedures, and Observe select examples from the clinic. Sofie Ceberg: Application to dynamic radiotherapy Observe full dosimetry under dynamic radiotherapy during respiratory motion, and Understand how the measurement of high resolution dose data in an

Fundamentals of x-ray dosimetry

International Nuclear Information System (INIS)

Roesch, W.C.

1976-01-01

Fundamental information about x-ray dosimetry is presented. Definitions are given and expanded on for dose, absorbed dose including microdosimetry, radiation physics (properties of the radiation that are important to dosimetry), and dosimetry (how the properties are dealt with in determining dose). 5 figs, 12 refs

SU-F-T-325: On the Use of Bolus in Dosimetry and Dose Reduction for Pacemaker and Defibrillator

International Nuclear Information System (INIS)

Liu, W; Kenneth, R; Higgins, S; Nath, R; Zhu, D; Trumpore, S; Chen, Z

2016-01-01

Purpose: Special attention is required in planning and administering radiation therapy to patients with cardiac implantable electronic devices (CIEDs), such as pacemaker and defibrillator. The range of dose to CIEDs that can induce malfunction is very large among CIEDs. Significant defects have been reported at dose as low as 0.15Gy. Failures causing discomfort have been reported at dose as low as 0.05Gy. Therefore, accurate estimation of dose to CIED and dose reduction are both important even if the dose is expected to be less than the often-used 2Gy limit. We investigate the use of bolus in in vivo dosimetry for CIEDs. Methods: In our clinic, high-energy beams (>10MV) are not used for patients with CIED due to neutron production. Solid water phantom measurements of out-of-field dose for a 6MV beam were performed using parallel plate chamber at different depth with and without 2cm bolus covering the chamber. In vivo dosimetry at skin surface above the pacemaker was performed with and without bolus for 3 patients with pacemaker <5cm from the field edge. Results: Chamber measured dose at depth ∼1 to 1.5cm below the skin surface, where the CIED is normally located, was reduced by ∼6% – 20% with bolus. The dose reduction became smaller at deeper depth. In vivo dosimetry at skin surface also yielded ∼20% – 60% lower dose when using bolus for the 3 patients. In general, TPS calculation underestimated the dose. The dose measured with bolus is closer to the dose at the depth of the pacemaker and less affected by contaminant electrons and linac head leakage. Conclusion: In vivo CIED dose measurements should be performed with 1 to 2cm bolus covering the dosimeter on the skin above the CIED for more accurate CIED dose estimation. The use of bolus also reduces the dose delivered to CIED.

SU-F-T-325: On the Use of Bolus in Dosimetry and Dose Reduction for Pacemaker and Defibrillator

Energy Technology Data Exchange (ETDEWEB)

Liu, W; Kenneth, R; Higgins, S; Nath, R [Yale University School of Medicine, New Haven, CT (United States); Zhu, D [Saint Thomas Hospital, Murfreesboro, TN (United States); Trumpore, S [Yale-New Haven Hospital, New Haven, CT (United States); Chen, Z [Yale New Haven Hospital, New Haven, CT (United States)

2016-06-15

Purpose: Special attention is required in planning and administering radiation therapy to patients with cardiac implantable electronic devices (CIEDs), such as pacemaker and defibrillator. The range of dose to CIEDs that can induce malfunction is very large among CIEDs. Significant defects have been reported at dose as low as 0.15Gy. Failures causing discomfort have been reported at dose as low as 0.05Gy. Therefore, accurate estimation of dose to CIED and dose reduction are both important even if the dose is expected to be less than the often-used 2Gy limit. We investigate the use of bolus in in vivo dosimetry for CIEDs. Methods: In our clinic, high-energy beams (>10MV) are not used for patients with CIED due to neutron production. Solid water phantom measurements of out-of-field dose for a 6MV beam were performed using parallel plate chamber at different depth with and without 2cm bolus covering the chamber. In vivo dosimetry at skin surface above the pacemaker was performed with and without bolus for 3 patients with pacemaker <5cm from the field edge. Results: Chamber measured dose at depth ∼1 to 1.5cm below the skin surface, where the CIED is normally located, was reduced by ∼6% – 20% with bolus. The dose reduction became smaller at deeper depth. In vivo dosimetry at skin surface also yielded ∼20% – 60% lower dose when using bolus for the 3 patients. In general, TPS calculation underestimated the dose. The dose measured with bolus is closer to the dose at the depth of the pacemaker and less affected by contaminant electrons and linac head leakage. Conclusion: In vivo CIED dose measurements should be performed with 1 to 2cm bolus covering the dosimeter on the skin above the CIED for more accurate CIED dose estimation. The use of bolus also reduces the dose delivered to CIED.

Comparison of dose response functions for EBT3 model GafChromic™ film dosimetry system.

Science.gov (United States)

Aldelaijan, Saad; Devic, Slobodan

2018-05-01

Different dose response functions of EBT3 model GafChromic™ film dosimetry system have been compared in terms of sensitivity as well as uncertainty vs. error analysis. We also made an assessment of the necessity of scanning film pieces before and after irradiation. Pieces of EBT3 film model were irradiated to different dose values in Solid Water (SW) phantom. Based on images scanned in both reflection and transmission mode before and after irradiation, twelve different response functions were calculated. For every response function, a reference radiochromic film dosimetry system was established by generating calibration curve and by performing the error vs. uncertainty analysis. Response functions using pixel values from the green channel demonstrated the highest sensitivity in both transmission and reflection mode. All functions were successfully fitted with rational functional form, and provided an overall one-sigma uncertainty of better than 2% for doses above 2 Gy. Use of pre-scanned images to calculate response functions resulted in negligible improvement in dose measurement accuracy. Although reflection scanning mode provides higher sensitivity and could lead to a more widespread use of radiochromic film dosimetry, it has fairly limited dose range and slightly increased uncertainty when compared to transmission scan based response functions. Double-scanning technique, either in transmission or reflection mode, shows negligible improvement in dose accuracy as well as a negligible increase in dose uncertainty. Normalized pixel value of the images scanned in transmission mode shows linear response in a dose range of up to 11 Gy. Copyright © 2018 Associazione Italiana di Fisica Medica. Published by Elsevier Ltd. All rights reserved.

EPR dosimetry - present and future

International Nuclear Information System (INIS)

Regulla, D.F.

1999-01-01

In the past, IAEA has played a central role in stipulating research and development in EPR high-dose standardisation as well as co-ordinating and organising international dose intercomparison programs, within the Member States of the United Nations from the mid-seventies till today. The future tasks of EPR dosimetry seem to tend towards different subjects such as biomarkers, biological radiation effects, post-accident dose reconstruction in the environment, and retrospective human dosimetry. The latter may be considered a promising tool for epidemiology on the way to re-define radiation risk of man for chronicle radiation exposures, based on e.g. South Ural civil population and radiation workers. There are on-going international activities in the field of standardising high-level dosimetry by the American Standards on Testing and Materials (ASTM), and the International Organisation of Standards (ISO) as well as those of the International Commission on Radiation Units and Measurements (ICRU) considering the establishment of relevant recommendations concerning industrial radiation processing, but also human dose reconstruction. (author)

Use of electron paramagnetic resonance dosimetry with tooth enamel for retrospective dose assessment. Report of a co-ordinated research project

CERN Document Server

2002-01-01

Electron paramagnetic resonance (EPR) dosimetry is a physical method for the assessment of absorbed dose from ionising radiation. It is based on the measurement of stable radiation induced radicals in human calcified tissues (primarily in tooth enamel). EPR dosimetry with teeth is now firmly established in retrospective dosimetry. It is a powerful method for providing information on exposure to ionising radiation many years after the event, since the 'signal' is 'stored' in the tooth or the bone. This technique is of particular relevance to relatively low dose exposures or when the results of conventional dosimetry are not available (e.g. in accidental circumstances). The use of EPR dosimetry, as an essential tool for retrospective assessment of radiation exposure is an important part of radioepidemiological studies and also provides data to select appropriate countermeasures based on retrospective evaluation of individual doses. Despite well established regulations and protocols for maintaining radiation pro...

Trends of personal dosimetry at atomic power plants

International Nuclear Information System (INIS)

Yamamura, Seini

1998-01-01

The individual dosimetry at the atomic power station is sorted for monthly dosimetry, daily dosimetry and special job dosimetry in high dose circumstance. Film badge (passive dosimeter) can measure gamma dose, beta dose and neutron dose respectively lower than about 0.1 mSv. While workers are in the radiation controlled area, they have to wear the dosimeters and the individual dose is accumulated for every one month. Recently the Silicon semiconductors detecting beta ray and neutron have been developed. With microcircuit technology and these new sensors, new multiple function dosimeter of the card size had been put to practical use. The result of dose measurement obtained by the electronic dosimeter is consistent well with the measurement of usual film badge and new dosimeter can determine the dose as low as 0.01 mSv. The result is stored in the non-volatile memory in the electronic personal dosimeter and held for more than one year without the power supply. The function to read data directly from the memory improves the reliability of the data protection. The realization of the unified radiation control system that uses the electronic personal dosimeter for monthly dosimetry is expected. (J.P.N.)

Investigation of the Spatial Resolution of MR-Based Polymer Gel Dosimetry versus Film Densitometry using Dose Modulation Transfer Function

Directory of Open Access Journals (Sweden)

Reza Moghadam-Drodkhani

2011-03-01

Full Text Available Introduction: The conventional methods of dosimetry are not capable of dosimetry in such a small volume of less than one cubic millimeter. Although the polymer gel dosimetry method based on magnetic resonance imaging (MRI could achieve three dimensional dosimetry with high resolution, a spatial resolution evaluation based on gel dose modulation transfer function has not been investigated yet. Therefore, in this study, the spatial resolution of two systems of film densitometry and polymer gel dosimetry based on MRI has been evaluated by using the dose modulation transfer function (DMTF.   Material and Methods: Kodak therapy verification films and MAGICA polymer gel samples were positioned below a brass absorption grid with different periodic slices (a/2= 280, 525, 1125 μm, which was placed in a water bath container to avoid regions of dose build-up just below the absorption grid and then irradiated with Cobalt-60 photons on a Theratron external-beam treatment unit. Dose variation under the brass grid was determined using a calibration curve, while transverse relaxation time (T2 as the selective parameter in a dose image based on multiple echo MRI with 1.5 Tesla GE Signa Echo Speed system (FOV=10 cm, matrix size=512 ×512, pixel size =0.199×0.199 mm2, TE = 20, 40, 60, 80 ms, TR=4200 ms, NEX = 4, slice thickness=2 mm, gap=1 mm was calculated. DMTF from the modulation depths of T2 and variation in film optical density after calibration would be achieved. The results of polymer gel were compared with film. Results: After deriving the dose distribution profile under the absorption grid, minima and maxima at the smallest period of a = 560 μm could scarcely be resolved, but the modulations due to a=2250 μm and a = 1050 μm grids could be discerned. The modulation depth for a=2250 μm grid was set to 100% and the other modulations were subsequently referred to this maximum modulation. For film densitometry at a = 1050 μm, the modulation depth was

Review of the correlation between results of cytogenetic dosimetry from blood lymphocytes and EPR dosimetry from tooth enamel for victims of radiation accidents

International Nuclear Information System (INIS)

Khvostunov, I.K.; Ivannikov, A.I.; Skvortsov, V.G.; Golub, E.V.; Nugis, V. Yu.

2015-01-01

The goal of this study was to compare dose estimates from electron paramagnetic resonance (EPR) dosimetry with teeth and cytogenetic dosimetry with blood lymphocytes for 30 victims of radiation accidents. The whole-body exposures estimated by tooth enamel EPR dosimetry were ranging from 0.01 to 9.3 Gy. Study group comprised victims exposed to acute and prolonged irradiation at high and low dose rate in different accidents. Blood samples were taken from each of them for cytogenetic analysis. Aberrations were scored and analysed according to International Atomic Energy Agency (IAEA) guidelines for conventional and FISH analysis. Tooth samples were collected in dental clinics after they had been extracted during ordinary practice. EPR dosimetry was performed according to the IAEA protocol. EPR dosimetry showed good correlation with dosimetry based on chromosomal analysis. All estimations of cytogenetic dose below detection limit coincide with EPR dose estimates within the ranges of uncertainty. The differences between cytogenetic and EPR assays may occur in a case of previous unaccounted exposure, non-homogeneous irradiation and due to contribution to absorbed dose from neutron irradiation. (authors)

Study of teflon pads as high doses dosemeters

International Nuclear Information System (INIS)

Teixeira, Maria Ines; Caldas, Linda V.E.

2013-01-01

The aim of this work is to study the Teflon, which is used as a binder in the manufacture of dosimetric tablets, for the feasibility of this material as high dose dosemeter. In this paper we used the technique of thermally stimulated luminescence (OSL) to characterize the dosimetric properties of Teflon. Teflon samples were exposed to different doses of radiation, using a source of gamma radiation ( 60 Co). It was obtained dose-response curve between 100 Gy to 50 kGy and reproducibility of OSL response. The preliminary results show that Teflon is a useful material to high dose dosimetry

In vivo dosimetry in radiation therapy in Sweden; In vivo-dosimetri inom straalbehandling i Sverige

Energy Technology Data Exchange (ETDEWEB)

Eriksson, Jacob; Blomquist, Michael (Norrlands universitetssjukhus, Umeaa (Sweden))

2010-07-15

A prerequisite for achieving high radiation safety for patients receiving external beam radiation therapy is that the hospitals have a quality assurance program. The program should include include monitoring of the radiation dose given to the patient. Control measurements are performed both at the system level and at the individual level. Control measurement is normally performed using in vivo dosimetry, e.g. a method to measure the radiation dose at the individual level during the actual radiation treatment time. In vivo dosimetry has proven to be an important tool to detect and prevent serious errors in patient treatment. The purpose of this research project was to identify the extent to which vivo dosimetry is used and the methods available for this at Swedish radiation therapy clinics. The authority also wanted to get an overall picture of how hospitals manage results of in vivo dosimetry, and how clinics control radiation dose when using modern treatment techniques. The report reflects the situation in Swedish radiotherapy clinics 2007. The report shows that all hospitals use some form of in vivo dosimetry. The instruments used are mainly diodes and termoluminiscence dosimeters

Applicability of thermoluminescent dosimeters in X-ray organ dose determination and in the dosimetry of systemic and boron neutron capture radiotherapy

International Nuclear Information System (INIS)

Aschan, C.

1999-01-01

The main detectors used for clinical dosimetry are ionisation chambers and semiconductors. Thermoluminescent (TL) dosimeters are also of interest because of their following advantages: (i) wide useful dose range, (ii) small physical size, (iii) no need for high voltage or cables, i.e. stand alone character, and (iv) tissue equivalence (LiF) for most radiation types. TL detectors can particularly be used for the absorbed dose measurements performed with the aim to investigate cases where dose prediction is difficult and not as part of a routine verification procedure. In this thesis, the applicability of TL detectors was studied in different clinical applications. Particularly, the major phenomena (e.g. energy dependence, sensitivity to high LET radiation, reproducibility) affecting on the precision and accuracy of TL detectors in the dose estimations were considered in this work. In organ dose determinations of diagnostic X-ray examinations, the TL detectors were found to be accurate within 5% (1 S.D.). For in viva studies using internal irradiation source, i.e. for systemic radiation therapy, a method for determining the absorbed doses to organs was introduced. The TL method developed was found to be able to estimate the absorbed doses to those critical organs near the body surface within 50%. In the mixed neutron-gamma field of boron neutron capture therapy (BNCT), TL detectors were used for gamma dose and neutron fluence measurements. They were found able to measure the neutron dose component with the accuracy of 16%, and therefore to be a useful addition to the activation foils in BNCT neutron dosimetry. The absorbed gamma doses can be measured with TL detectors within 20% in the mixed neutron-gamma field, which enables in viva measurements at BNCT beams with approximately the same accuracy. In this study, the uncertainties of TL dosimeters were found to be high but not essentially greater than those in other measurement techniques used for clinical dosimetry

Radiation processing dosimetry - past, present and future

International Nuclear Information System (INIS)

McLaughlin, W.L.

1999-01-01

Since the two United Nations Conferences were held in Geneva in 1955 and 1958 on the Peaceful Uses of Atomic Energy and the concurrent foundation of the International Atomic Energy Agency in 1957, the IAEA has fostered high-dose dosimetry and its applications. This field is represented in industrial radiation processing, agricultural programmes, and therapeutic and preventative medicine. Such dosimetry is needed specifically for pest and quarantine control and in the processing of medical products, pharmaceuticals, blood products, foodstuffs, solid, liquid and gaseous wastes, and a variety of useful commodities, e.g. polymers, composites, natural rubber and elastomers, packaging, electronic, and automotive components, as well as in radiotherapy. Improvements and innovations of dosimetry materials and analytical systems and software continue to be important goals for these applications. Some of the recent advances in high-dose dosimetry include tetrazolium salts and substituted polydiacetylene as radiochromic media, on-line real-time as well as integrating semiconductor and diamond-detector monitors, quantitative label dosimeters, photofluorescent sensors for broad dose range applications, and improved and simplified parametric and computational codes for imaging and simulating 3D radiation dose distributions in model products. The use of certain solid-state devices, e.g. optical quality LiF, at low (down to 4K) and high (up to 500 K) temperatures, is of interest for materials testing. There have also been notable developments in experimental dose mapping procedures, e.g. 2D and 3D dose distribution analyses by flat-bed optical scanners and software applied to radiochromic and photofluorescent images. In addition, less expensive EPR spectrometers and new EPR dosimetry materials and high-resolution semiconductor diode arrays, charge injection devices, and photostimulated storage phosphors have been introduced. (author)

Dosimetry in computerized tomography and evaluation of doses in organs in thorax scanning

International Nuclear Information System (INIS)

Alonso, Thêssa Cristina

2016-01-01

Computed tomography has promoted improvement of the diagnostic process by producing anatomical cut images with high quality and contrast between soft tissues which have very similar absorption of the X-ray beams. The objective of this study is to evaluate the technological park of CT in Brazil correlated with the wide world, and carry out studies of experimental dosimetry to understand the dose distribution feature using phantoms and different methods of measurement of kerma index, as well as perform measures of local doses in sensitive organs. To study the scanner geographic distribution and supply of computed tomography tests in Brazil, a comparison has been made with results found with the specified reference by Brazilian law (Ordinance GM / MS No. 1101, 2002; Resolution RE nº1016, 2006). For dosimetry studies, It was used a standard chest phantom and the anthropomorphic phantom. For image quality evaluation, it was used the CATPHAN-600 phantom. Scans were performed in a GE scanner, Discovery model with 64 channels. Dose measurements have been performed by using a pencil ionization chamber, thermoluminescent dosimeters and radiochromic film strips. Sensitive organ shielding devices were evaluated in order to verify their efficiency in organ dose reduction and its influence in the quality of image. Considering Brazilian population, the scanner park showed a greater amount than the minimum parameter recommended by Brazilian law. Dose measurements using three different methods showed the correct procedure of metrological reliability of the measurement system. The findings and conclusions of this study may contribute to the improvement of local practices in Computed Tomography tests, inserted in context of radiological protection in order to define reference levels for optimized diagnosis, and image quality control. (author)

Validation and application of polymer gel dosimetry for the dose verification of an intensity-modulated arc therapy (IMAT) treatment

International Nuclear Information System (INIS)

Vergote, K; Deene, Y de; Duthoy, W; Gersem, W de; Neve, W de; Achten, E; Wagter, C de

2004-01-01

Polymer gel dosimetry was used to assess an intensity-modulated arc therapy (IMAT) treatment for whole abdominopelvic radiotherapy. Prior to the actual dosimetry experiment, a uniformity study on an unirradiated anthropomorphic phantom was carried out. A correction was performed to minimize deviations in the R2 maps due to radiofrequency non-uniformities. In addition, compensation strategies were implemented to limit R2 deviations caused by temperature drift during scanning. Inter- and intra-slice R2 deviations in the phantom were thereby significantly reduced. This was verified in an investigative study where the same phantom was irradiated with two rectangular superimposed beams: structural deviations between gel measurements and computational results remained below 3% outside high dose gradient regions; the spatial shift in those regions was within 2.5 mm. When comparing gel measurements with computational results for the IMAT treatment, dose deviations were noted in the liver and right kidney, but the dose-volume constraints were met. Root-mean-square differences between both dose distributions were within 5% with spatial deviations not more than 2.5 mm. Dose fluctuations due to gantry angle discretization in the dose computation algorithm were particularly noticeable in the low-dose region

The Mayak Worker Dosimetry System (MWDS-2013): implementation of the dose calculations

International Nuclear Information System (INIS)

Zhdanov, A.; Vostrotin, V.; Efimov, A.; Birchall, A.; Puncher, M.

2017-01-01

The calculation of internal doses for the Mayak Worker Dosimetry System (MWDS-2013) involved extensive computational resources due to the complexity and sheer number of calculations required. The required output consisted of a set of 1000 hyper-realizations: each hyper-realization consists of a set (1 for each worker) of probability distributions of organ doses. This report describes the hardware components and computational approaches required to make the calculation tractable. Together with the software, this system is referred to here as the 'PANDORA system'. It is based on a commercial SQL server database in a series of six work stations. A complete run of the entire Mayak worker cohort entailed a huge amount of calculations in PANDORA and due to the relatively slow speed of writing the data into the SQL server, each run took about 47 days. Quality control was monitored by comparing doses calculated in PANDORA with those in a specially modified version of the commercial software 'IMBA Professional Plus'. Suggestions are also made for increasing calculation and storage efficiency for future dosimetry calculations using PANDORA. (authors)

High-accuracy dosimetry study for intensity-modulated radiation therapy(IMRT) commissioning

Energy Technology Data Exchange (ETDEWEB)

Jeong, Hae Sun

2010-02-15

Intensity-modulated radiation therapy (IMRT), an advanced modality of high-precision radiotherapy, allows for an increase in dose to the tumor volume without increasing the dose to nearby critical organs. In order to successfully achieve the treatment, intensive dosimetry with accurate dose verification is necessary. A dosimetry for IMRT, however, is a challenging task due to dosimetric ally unfavorable phenomena such as dramatic changes of the dose at the field boundaries, dis-equilibrium of the electrons, non-uniformity between the detector and the phantom materials, and distortion of scanner-read doses. In the present study, therefore, the LEGO-type multi-purpose dosimetry phantom was developed and used for the studies on dose measurements and correction. Phantom materials for muscle, fat, bone, and lung tissue were selected after considering mass density, atomic composition, effective atomic number, and photon interaction coefficients. The phantom also includes dosimeter holders for several different types of detectors including films, which accommodates a construction of different designs of phantoms as necessary. In order to evaluate its performance, the developed phantom was tested by measuring the point dose and the percent depth dose (PDD) for small size fields under several heterogeneous conditions. However, the measurements with the two types of dosimeter did not agree well for the field sizes less than 1 x 1 cm{sup 2} in muscle and bone, and less than 3 x 3 cm{sup 2} in air cavity. Thus, it was recognized that several studies on small fields dosimetry and correction methods for the calculation with a PMCEPT code are needed. The under-estimated values from the ion chamber were corrected with a convolution method employed to eliminate the volume effect of the chamber. As a result, the discrepancies between the EBT film and the ion chamber measurements were significantly decreased, from 14% to 1% (1 x 1 cm{sup 2}), 10% to 1% (0.7 x 0.7 cm{sup 2}), and 42

Gel dosimetry for conformal radiotherapy

Energy Technology Data Exchange (ETDEWEB)

Gambarini, G [Department of Physics of the University and INFN, Milan (Italy)

2005-07-01

With the continuum development of conformal radio therapies, aimed at delivering high dose to tumor tissue and low dose to the healthy tissue around, the necessities has appeared of suitable improvement of dosimetry techniques giving the possibility of obtaining dose images to be compared with diagnostic images. Also if wide software has been developed for calculating dose distributions in the fields of various radiotherapy units, experimental verifications are necessary, in particular in the case of complex geometries in conformal radiotherapy. Gel dosimetry is a promising method for imaging the absorbed dose in tissue-equivalent phantoms, with the possibility of 3D reconstruction of the spatial dose distribution, with milli metric resolution. Optical imaging of gel dosimeters, based on visible light absorbance analysis, has shown to be a reliable technique for achieving dose distributions. (Author)

Comparison of Real-Time Intraoperative Ultrasound-Based Dosimetry With Postoperative Computed Tomography-Based Dosimetry for Prostate Brachytherapy

International Nuclear Information System (INIS)

Nag, Subir; Shi Peipei; Liu Bingren; Gupta, Nilendu; Bahnson, Robert R.; Wang, Jian Z.

2008-01-01

Purpose: To evaluate whether real-time intraoperative ultrasound (US)-based dosimetry can replace conventional postoperative computed tomography (CT)-based dosimetry in prostate brachytherapy. Methods and Materials: Between December 2001 and November 2002, 82 patients underwent 103 Pd prostate brachytherapy. An interplant treatment planning system was used for real-time intraoperative transrectal US-guided treatment planning. The dose distribution was updated according to the estimated seed position to obtain the dose-volume histograms. Postoperative CT-based dosimetry was performed a few hours later using the Theraplan-Plus treatment planning system. The dosimetric parameters obtained from the two imaging modalities were compared. Results: The results of this study revealed correlations between the US- and CT-based dosimetry. However, large variations were found in the implant-quality parameters of the two modalities, including the doses covering 100%, 90%, and 80% of the prostate volume and prostate volumes covered by 100%, 150%, and 200% of the prescription dose. The mean relative difference was 38% and 16% for doses covering 100% and 90% of the prostate volume and 10% and 21% for prostate volumes covered by 100% and 150% of the prescription dose, respectively. The CT-based volume covered by 200% of the prescription dose was about 30% greater than the US-based one. Compared with CT-based dosimetry, US-based dosimetry significantly underestimated the dose to normal organs, especially for the rectum. The average US-based maximal dose and volume covered by 100% of the prescription dose for the rectum was 72 Gy and 0.01 cm 3 , respectively, much lower than the 159 Gy and 0.65 cm 3 obtained using CT-based dosimetry. Conclusion: Although dosimetry using intraoperative US-based planning provides preliminary real-time information, it does not accurately reflect the postoperative CT-based dosimetry. Until studies have determined whether US-based dosimetry or

Dosimetry system of the RB reactor

International Nuclear Information System (INIS)

Lolic, B.; Vukadin, D.

1962-01-01

Although RB reactor is operated at very low power levels, safety and dosimetry systems have high importance. This paper shows detailed dosimetry system with fundamental typical components. Estimated radiation doses dependent on reactor power are given at some characteristic points in the rooms nearby reactor

Quasi 3D dosimetry (EPID, conventional 2D/3D detector matrices)

International Nuclear Information System (INIS)

Bäck, A

2015-01-01

Patient specific pretreatment measurement for IMRT and VMAT QA should preferably give information with a high resolution in 3D. The ability to distinguish complex treatment plans, i.e. treatment plans with a difference between measured and calculated dose distributions that exceeds a specified tolerance, puts high demands on the dosimetry system used for the pretreatment measurements and the results of the measurement evaluation needs a clinical interpretation. There are a number of commercial dosimetry systems designed for pretreatment IMRT QA measurements. 2D arrays such as MapCHECK ® (Sun Nuclear), MatriXX Evolution (IBA Dosimetry) and OCTAVIOUS ® 1500 (PTW), 3D phantoms such as OCTAVIUS ® 4D (PTW), ArcCHECK ® (Sun Nuclear) and Delta 4 (ScandiDos) and software for EPID dosimetry and 3D reconstruction of the dose in the patient geometry such as EPIDose TM (Sun Nuclear) and Dosimetry Check TM (Math Resolutions) are available. None of those dosimetry systems can measure the 3D dose distribution with a high resolution (full 3D dose distribution). Those systems can be called quasi 3D dosimetry systems. To be able to estimate the delivered dose in full 3D the user is dependent on a calculation algorithm in the software of the dosimetry system. All the vendors of the dosimetry systems mentioned above provide calculation algorithms to reconstruct a full 3D dose in the patient geometry. This enables analyzes of the difference between measured and calculated dose distributions in DVHs of the structures of clinical interest which facilitates the clinical interpretation and is a promising tool to be used for pretreatment IMRT QA measurements. However, independent validation studies on the accuracy of those algorithms are scarce. Pretreatment IMRT QA using the quasi 3D dosimetry systems mentioned above rely on both measurement uncertainty and accuracy of calculation algorithms. In this article, these quasi 3D dosimetry systems and their use in patient specific

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

Science.gov (United States)

Gomà, Carles; Safai, Sairos; Vörös, Sándor

2017-06-21

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

CT dosimetry computer codes: Their influence on radiation dose estimates and the necessity for their revision under new ICRP radiation protection standards

International Nuclear Information System (INIS)

Kim, K. P.; Lee, J.; Bolch, W. E.

2011-01-01

Computed tomography (CT) dosimetry computer codes have been most commonly used due to their user friendliness, but with little consideration for potential uncertainty in estimated organ dose and their underlying limitations. Generally, radiation doses calculated with different CT dosimetry computer codes were comparable, although relatively large differences were observed for some specific organs or tissues. The largest difference in radiation doses calculated using different computer codes was observed for Siemens Sensation CT scanners. Radiation doses varied with patient age and sex. Younger patients and adult females receive a higher radiation dose in general than adult males for the same CT technique factors. There are a number of limitations of current CT dosimetry computer codes. These include unrealistic modelling of the human anatomy, a limited number of organs and tissues for dose calculation, inability to alter patient height and weight, and non-applicability to new CT technologies. Therefore, further studies are needed to overcome these limitations and to improve CT dosimetry. (authors)

Thermocurrent dosimetry with high purity aluminum oxide

Energy Technology Data Exchange (ETDEWEB)

Fullerton, G.D.; Cameron, J.R.; Moran, P.R.

1976-01-01

The application of thermocurrent (TC) to ionizing radiation dosimetry was studied. It was shown that TC in alumina (Al/sub 2/O/sub 3/) has properties that are suited to personnel dosimetry and environmental monitoring. TC dosimeters were made from thin disks of alumina. Aluminum electrodes were evaporated on each side: on one face a high voltage electrode and on the opposite face a measuring electrode encircled by a guard ring. Exposure to ionizing radiation resulted in stored electrons and holes in metastable trapping sites. The signal was read-out by heating the dosimeter with a voltage source and picnometer connected in series between the opposite electrodes. The thermally remobilized charge caused a transient TC. The thermogram, TC versus time or temperature, is similar to a TL glow curve. Either the peak current or the integrated current is a measure of absorbed dose. Six grades of alumina were studied from a total of four commercial suppliers. All six materials displayed radiation induced TC signals. Sapphire of uv-grade quality from the Adolf Meller Co. (AM) had the best dosimetry properties of those investigated. Sources of interference were studied. Thermal fading, residual signal and radiation damage do not limit TC dosimetry. Ultraviolet light can induce a TC response but it is readily excluded with uv-opaque cladding. Improper surface preparation prior to electrode evaporation was shown to cause interference. A spurious TC signal resulted from polarization of surface contaminants. Spurious TC was reduced by improved cleaning prior to electrode application. Polished surfaces resulted in blocking electrodes and caused a sensitivity shift due to radiation induced thermally activated polarization. This was not observed with rough cut surfaces.

Thermocurrent dosimetry with high purity aluminum oxide

International Nuclear Information System (INIS)

Fullerton, G.D.; Cameron, J.R.; Moran, P.R.

1976-01-01

The application of thermocurrent (TC) to ionizing radiation dosimetry was studied. It was shown that TC in alumina (Al 2 O 3 ) has properties that are suited to personnel dosimetry and environmental monitoring. TC dosimeters were made from thin disks of alumina. Aluminum electrodes were evaporated on each side: on one face a high voltage electrode and on the opposite face a measuring electrode encircled by a guard ring. Exposure to ionizing radiation resulted in stored electrons and holes in metastable trapping sites. The signal was read-out by heating the dosimeter with a voltage source and picnometer connected in series between the opposite electrodes. The thermally remobilized charge caused a transient TC. The thermogram, TC versus time or temperature, is similar to a TL glow curve. Either the peak current or the integrated current is a measure of absorbed dose. Six grades of alumina were studied from a total of four commercial suppliers. All six materials displayed radiation induced TC signals. Sapphire of uv-grade quality from the Adolf Meller Co. (AM) had the best dosimetry properties of those investigated. Sources of interference were studied. Thermal fading, residual signal and radiation damage do not limit TC dosimetry. Ultraviolet light can induce a TC response but it is readily excluded with uv-opaque cladding. Improper surface preparation prior to electrode evaporation was shown to cause interference. A spurious TC signal resulted from polarization of surface contaminants. Spurious TC was reduced by improved cleaning prior to electrode application. Polished surfaces resulted in blocking electrodes and caused a sensitivity shift due to radiation induced thermally activated polarization. This was not observed with rough cut surfaces

High electron beam dosimetry using ZrO2

International Nuclear Information System (INIS)

Lueza M, F.; Rivera M, T.; Azorin N, J.; Garcia H, M.

2009-10-01

This paper reports the experimental results of studying the thermoluminescent (Tl) properties of ZrO 2 powder embedded in polytetrafluorethylene (PTFE) exposed to high energy electron beam from linear accelerators (Linac). Structural and morphological characteristics were also reported. Irradiations were conducted using high energy electrons beams in the range from 2 to 18 MeV. Pellets of ZrO 2 +PTFE were produced using polycrystalline powder grown by the precipitation method. These pellets presented a Tl glow curve exhibiting an intense glow peak centered at around 235 C. Tl response as a function of high electron absorbed dose was linear in the range from 2 to 30 Gy. Repeatability determined by exposing a set of pellets repeatedly to the same electron absorbed dose was 0.5%. Fading along 30 days was about 50%. Then, results obtained in this study suggest than ZrO 2 +PTFE pellets could be used for high energy electron beam dosimetry provided fading correction is accounted for. (Author)

European protocol for neutron dosimetry for external beam therapy

International Nuclear Information System (INIS)

Broerse, J.J.; Mijnheer, B.J.; Williams, J.R.

1981-01-01

The paper attempts to serve the needs of European centres participating in the High LET Therapy Project Group set up under the sponsorship of The European Organization for Research on Treatment of Cancer, to promote cooperation between physicists involved in fast neutron therapy and establish a common basis for neutron dosimetry. Differences in dosimetry procedures between European and American Groups are indicated if relevant. The subject is dealt with under the following main headings: principles of dosimetry of neutron fields, dosimetric methods, physical parameters, determination of absorbed dose at a reference point, determination of absorbed dose at any point, check of absorbed dose given to a patient, dosimetry intercomparisons between institutes. There is an ample bibliography. (U.K.)

Verification of the plan dosimetry for high dose rate brachytherapy using metal-oxide-semiconductor field effect transistor detectors

International Nuclear Information System (INIS)

Qi Zhenyu; Deng Xiaowu; Huang Shaomin; Lu Jie; Lerch, Michael; Cutajar, Dean; Rosenfeld, Anatoly

2007-01-01

The feasibility of a recently designed metal-oxide-semiconductor field effect transistor (MOSFET) dosimetry system for dose verification of high dose rate (HDR) brachytherapy treatment planning was investigated. MOSFET detectors were calibrated with a 0.6 cm 3 NE-2571 Farmer-type ionization chamber in water. Key characteristics of the MOSFET detectors, such as the energy dependence, that will affect phantom measurements with HDR 192 Ir sources were measured. The MOSFET detector was then applied to verify the dosimetric accuracy of HDR brachytherapy treatments in a custom-made water phantom. Three MOSFET detectors were calibrated independently, with the calibration factors ranging from 0.187 to 0.215 cGy/mV. A distance dependent energy response was observed, significant within 2 cm from the source. The new MOSFET detector has a good reproducibility ( 2 =1). It was observed that the MOSFET detectors had a linear response to dose until the threshold voltage reached approximately 24 V for 192 Ir source measurements. Further comparison of phantom measurements using MOSFET detectors with dose calculations by a commercial treatment planning system for computed tomography-based brachytherapy treatment plans showed that the mean relative deviation was 2.2±0.2% for dose points 1 cm away from the source and 2.0±0.1% for dose points located 2 cm away. The percentage deviations between the measured doses and the planned doses were below 5% for all the measurements. The MOSFET detector, with its advantages of small physical size and ease of use, is a reliable tool for quality assurance of HDR brachytherapy. The phantom verification method described here is universal and can be applied to other HDR brachytherapy treatments

Radiation chemistry of anionic disazo dyes in Cellophane films applications for high-dose dosimetry

Energy Technology Data Exchange (ETDEWEB)

McLaughlin, W.L.William L

2003-06-01

Thin transparent Cellophane films containing anionic disazo 'Direct' dyes, e.g. blue Cellophanes, have long been used as monitors of large absorbed doses of ionizing radiation (10-300 kGy) and especially for mapping electron-beam dose profiles. Examples of dyes for such purposes are variations on forms of the disazo dyes, Direct Orange, Direct Violet or Direct Blue. The films have a thickness of 25.6 {mu}m (+0.1 {mu}m) and are available in rolls of either 30 mx0.51 m or 60 mx0.76 m. Such dyed Cellophanes are typically lightfast but can readily be bleached irreversibly by ionizing radiation, as a means of dosimetry using spectrophotometry as the analytical tool. The radiation response is markedly dependent on temperature and relative humidity during irradiation. The reaction is initiated mainly by dehydrogenation and nitrosation upon electrophilic reductive attack on the dye molecule by the thermal electrons, at initial reaction rate constants in the range 10{sup 5}-10{sup 6} s{sup -1}.

Determination of effective dose for workers hemodynamics service using double dosimetry

International Nuclear Information System (INIS)

Ruiz Lopez, M. A.; Lobato Munoz, M.; Jodar Lopez, C. A.; Ramirez Ros, J. C.; Jerez Sainz, M. I.; Pamos Urena, M.; Carrasco Rodriguez, J. L.

2013-01-01

The use of an additional dosimeter at the level of the neck above the lead apron we can provide an indication of the dose in the head (the Crystal dose). In addition, it is possible to combine the two readings of the dosimeter to provide an improved estimate of the effective dose. In the hemodynamics service of our Hospital we have maintained a worker for 3 years with the double dosimetry read monthly. With the readings from these dosimeters will do following algorithms, several estimates of the effective dose to see if, with working conditions that occur in this service, it would be necessary to extend this practice to the rest of the workers to get a better estimation of effective dose. (Author)

Retrospective dosimetry of Chernobyl liquidators

International Nuclear Information System (INIS)

Chumak, V.V.; Bakhanova, E.V.; Sholom, S.V.; Pasalskaya, L.F.; Bouville, A.; Krjuchkov, V.P.

2000-01-01

The numerous cohort of Chernobyl liquidators is a very attractive subject for epidemiological follow up due to high levels of exposure, age-gender distribution and availability of patients for medical examination. However, dosimetric information related to this population is incomplete, in many cases the quality of available dose records is doubtful and uncertainties of all dose values are not determined. Naive attempts to evaluate average doses on the basis of such factors as 'distance from the reactor' obviously fail due to large variation of tasks and workplace contamination. Therefore, prior to any sensible consideration of liquidators as a subject of epidemiological study, their doses should be evaluated (reevaluated) using the methods of retrospective dosimetry. Retrospective dosimetry in general got significant development over the last decade. However, most of the retrospective dosimetry techniques are time consuming, expensive and possess sensitivity threshold. Therefore, application of retrospective dosimetry for the needs of epidemiological follow up studies requires development of certain strategy. This strategy depends, of coarse, on the epidemiological design of the study, availability of resources and dosimetric information related to the time of clean up. One of the strategies of application of retrospective dosimetry may be demonstrated on the example of a cohort study with occasional nested case control consideration. In this case, the tools are needed for validation of existing dose records (of not always known quality), screening of the study cohort with express dosimetric method called to determine possible dose ranges, and 'state-of-the-art' assessment of individual doses for selected subjects (cases and controls). Verification of dose records involves analysis of the statistical regularities of dose distributions and detection of possible extraneous admixtures (presumably falsified dose records). This work is performed on impersonified data

Radiochromic film dosimetry

International Nuclear Information System (INIS)

Soares, Christopher G.

2006-01-01

The object of this paper is to give a new user some practical information on the use of radiochromic films for medical applications. While various aspects of radiochromic film dosimetry for medical applications have been covered in some detail in several other excellent review articles which have appeared in the last few years [Niroomand-Rad, A., Blackwell, C.R., Coursey, B.M., Gall, K.P., McLaughlin, W.L., Meigooni, A.S., Nath, R., Rodgers, J.E., Soares, C.G., 1998. Radiochromic dosimetry: recommendations of the AAPM Radiation Therapy Committee Task Group 55. Med. Phys. 25, 2093-2115; Dempsey, J.F., Low, D.A., Mutic, S., Markman, J., Kirov, A.S., Nussbaum, G.H., Williamson, J.F., 2000. Validation of a precision radiochromic film dosimetry system for quantitative two-dimensional imaging of acute exposure dose distributions. Med. Phys. 27, 2462-2475; Butson, M.J., Yu, P.K.N., Cheung, T., Metcalfe, P., 2003. Radiochromic film for medical radiation dosimetry. Mater. Sci. Eng. R41, 61-120], it is the intent of the present author to present material from a more user-oriented and practical standpoint. That is, how the films work will be stressed much less than how to make the films work well. The strength of radiochromic films is most evident in applications where there is a very high dose gradient and relatively high absorbed dose rates. These conditions are associated with brachytherapy applications, measurement of small fields, and at the edges (penumbra regions) of larger fields

In vivo dosimetry with thermoluminescent dosimeters in radiotherapy: entrance and exit doses

International Nuclear Information System (INIS)

Alves, C.; Lopes, M.C.

2000-01-01

In vivo dosimetry, by entrance and exit dose measurements, is a vital part of a radiotherapy quality assurance program. The uncertainty associated with dose delivery is internationally accepted to be within 5% or inferior depending on the tumor pathology. Thermoluminescent dosimetry is one of the dosimetric techniques used to verify the agreement between delivered and prescribed doses. Nevertheless, it requires a very accurate calibration methodology. We have used LiF chips (4.5 mm diameter and 0.8 mm thick) calibrated towards a PTW ionization chamber of 0.3 cc, in three photon energies: Co-60, 4 and 6 MeV. The TLD reader used was a Rialto 688 from NE Technology and the annealing oven the Eurotherm type 815. The calibration methodology relies on the experimental determination of individual correction factors and on a correction factor derived from a control group of dosimeters. The exit and entrance dose measurements are performed in quite different situations. To be able to achieve those two quantities with TLD, these should be independently calibrated according to the measurement conditions. Alternatively, we can use a single calibration, in entrance dose, and convert the result to the exit dose value by introducing some correction factors. These corrections are related to the different measurement depths and to the different backscattering contributions. We have proved that within an acceptable error we can perform a single calibration and adopt the correction factors which are energy and field size dependent. (author)

Retrospective Dosimetry: Dose Analysis From Tooth Enamel Using Electron Spin Resonance (ESR)

International Nuclear Information System (INIS)

Mohd Rodzi Ali; Rahimah Abdul Rahim; Noraisyah Yusof; Syed Asraf Fahlawi Wafa Syed Mohd Ghazi; Juliana Mahamad Napiah; Yahaya Talib; Rehir Dahalan

2014-01-01

The radiation dose should be accurately measured in order to relate its effect to the cells. The assessment of dose usually performed using biological dosimetry techniques. However, the reduction of lymphocytes (white blood cells) after the time period results in inaccuracy of dose measurement. An alternative method used is the application of Electron Spin Resonance (ESR) using tooth enamel. In this study, tooth enamels were evaluated and used to measure the individual absorbed dose from the background. The basic tooth features that would affect dose measurement were discussed. The results show this technique is capable and effective for retrospective dose measurement and useful for the study of radiation effect to human. (author)

Skin dose assessment in routine personnel beta/gamma dosimetry

International Nuclear Information System (INIS)

Christensen, P.

1980-01-01

The International Commission on Radiological Protection (Publication 26) has recommended a tissue depth of 5 to 10 mg.cm -2 for skin dose assessments. This requirement is generally not fulfilled by routine monitoring procedures because of practical difficulties in using very thin dosemeters with low sensitivity and therefore a high minimum detectable dose. Especially for low-energy beta-ray exposures underestimations of the skin dose by a factor of more than ten may occur. Low-transparent graphite-mixed sintered LiF and Li 2 B 4 0 7 : Mn dosemeters were produced which show a skin-equivalent response to beta and gamma exposures over a wide range of energies. These have found wide-spread application for extremity dosimetry but have not yet been generally introduced in routine personnel beta/gamma monitoring. The following adaptations of existing routine monitoring systems for improved skin dose assessments have been investigated: 1) Placement of a supplementary, thin, skin-dose equivalent dosemeter in the TLD badge to give additional information on low-energy exposures. 2) Introduction of a second photomultiplier in the read-out chamber which enables a simultaneous determination of emitted TL from both sides of the dosemeter separately. This method makes use of the selfshielding of the dosemeter to give information on the low-energy dose contribution. 3) By diffusion of Li 2 B 4 0 7 into solid LiF-dosemeters it was possible to produce a surface layer with a new distinct glow-peak at about 340 deg C which is not present in the undiffused part of the LiF chip, and which can be utilized for the assessment of the skin-dose. Data on energy response and accuracy of dose measurement for beta/gamma exposures are given for the three methods and advantages and disadvantages are discussed (H.K.)

Extremity dosimetry in medical applications within Europe: an overview of doses and monitoring practices

International Nuclear Information System (INIS)

Donadille, Laurent; Carinou, E.; Ginjaume, M.; Jankowski, J.; Rimpler, A.; Sans Merce, M.; Vanhavere, F.

2008-01-01

Full text: Some activities of the EURADOS Working Group 9 (WG9) related to the radiation protection dosimetry of medical staff were funded by the European Commission in the framework of the CONRAD project, Work Package 7. The objective of WG9 was to promote and co-ordinate research activities for the assessment of occupational exposure to staff at workplaces in therapeutic and diagnostic radiology and nuclear medicine. At these workplaces, from the point of view of the individual monitoring for external radiation, the skin of the fingers is generally the limiting organ. Subgroup 1 of WG9 had as main objective the study of the use of extremity dosemeters in medical radiation fields. The wide variety of radiation field characteristics present in medicine together with the difficulties of measuring a local dose which should be representative for the maximum skin dose using one single detector, makes it difficult to perform extremity dosimetry with an accuracy similar to that of whole-body one. A recent intercomparison organised by WG9 showed that some types of dosemeters significantly underestimate or overestimate skin doses. Subgroup 1 carried out a thorough literature review on extremity dosimetry issues. It covered diagnostic and therapeutic nuclear medicine and PET, interventional radiology and cardiology, and brachytherapy. It has notably pointed out the consensus about the requirement of regular extremity dose monitoring for nuclear medicine and PET, and the great difficulty of measuring extremity doses for procedures in interventional radiology and cardiology, activities for which routine extremity dose monitoring has been found to be poor. Furthermore, information on the status of extremity dosimetry in medical applications and associated monitoring practices was gathered from 7 European countries: France, Germany, Greece, Ireland, Poland, Spain and Switzerland. Interpretation of the data was not easy because of the wide range of procedures involved and also

Comparison of absorbed dose determinations using the IAEA dosimetry protocol and the ferrous sulphate dosimeter

International Nuclear Information System (INIS)

Mattsson, Olof

1988-01-01

In 1985 a comparison of different revised protocols for the dosimetry of high-energy photon and electron beams was published (Mattsson, 1985). The conclusions were that the agreement in absorbed dose to water determined using the different protocols is very good and that the agreement between ionization chamber and ferrous sulphate dosimetry is generally good. For electron beams the differences obtained with the ionization chamber and ferrous sulphate dosimeters were up to about 2%. The influence of the energy and angular distribution of the electron beams on the ionization chamber dosimetry is not fully considered in the dosimetry protocols. The basis for the ionization chamber dosimetry has recently been changed when the Bureau International des Poids et Mesures (BIPM) in 1986 changed the air-kerma standard. The reason was the adaption of the new stopping-power values reported in the ICRU Report No. 37. To achieve consistency in the ionization chamber dosimetry the interaction coefficients and correction factors given in the dosimetry protocols should also be based on the same set of stopping-power values. This is not the case with the protocols included in the comparison made by Mattsson. However, in the international code of practice by the International Atomic Energy Agency (IAEA, 1987) the new stopping-power values have been used. The formalism is the same as in most of the previous protocols. Mattsson et al. (1989) have shown that the differences in the various steps cancel out for the protocols published by NACP (1980) and by IAEA (1987) for cobalt-60 gamma quality. However, it is also of interest to investigate the influence of the new air-kerma standard and the new values on coefficients and factors given in the IAEA protocol for other beam qualities. Therefore, the data given by Mattsson (1985) have been recalculated using the new air-kerma standard and the IAEA protocol

Evaluation of Gafchromic EBT-XD film, with comparison to EBT3 film, and application in high dose radiotherapy verification

Science.gov (United States)

Palmer, Antony L.; Dimitriadis, Alexis; Nisbet, Andrew; Clark, Catharine H.

2015-11-01

There is renewed interest in film dosimetry for the verification of dose delivery of complex treatments, particularly small fields, compared to treatment planning system calculations. A new radiochromic film, Gafchromic EBT-XD, is available for high-dose treatment verification and we present the first published evaluation of its use. We evaluate the new film for MV photon dosimetry, including calibration curves, performance with single- and triple-channel dosimetry, and comparison to existing EBT3 film. In the verification of a typical 25 Gy stereotactic radiotherapy (SRS) treatment, compared to TPS planned dose distribution, excellent agreement was seen with EBT-XD using triple-channel dosimetry, in isodose overlay, maximum 1.0 mm difference over 200-2400 cGy, and gamma evaluation, mean passing rate 97% at 3% locally-normalised, 1.5 mm criteria. In comparison to EBT3, EBT-XD gave improved evaluation results for the SRS-plan, had improved calibration curve gradients at high doses, and had reduced lateral scanner effect. The dimensions of the two films are identical. The optical density of EBT-XD is lower than EBT3 for the same dose. The effective atomic number for both may be considered water-equivalent in MV radiotherapy. We have validated the use of EBT-XD for high-dose, small-field radiotherapy, for routine QC and a forthcoming multi-centre SRS dosimetry intercomparison.

Evaluation of Gafchromic EBT-XD film, with comparison to EBT3 film, and application in high dose radiotherapy verification

International Nuclear Information System (INIS)

Palmer, Antony L; Dimitriadis, Alexis; Nisbet, Andrew; Clark, Catharine H

2015-01-01

There is renewed interest in film dosimetry for the verification of dose delivery of complex treatments, particularly small fields, compared to treatment planning system calculations. A new radiochromic film, Gafchromic EBT-XD, is available for high-dose treatment verification and we present the first published evaluation of its use. We evaluate the new film for MV photon dosimetry, including calibration curves, performance with single- and triple-channel dosimetry, and comparison to existing EBT3 film. In the verification of a typical 25 Gy stereotactic radiotherapy (SRS) treatment, compared to TPS planned dose distribution, excellent agreement was seen with EBT-XD using triple-channel dosimetry, in isodose overlay, maximum 1.0 mm difference over 200–2400 cGy, and gamma evaluation, mean passing rate 97% at 3% locally-normalised, 1.5 mm criteria. In comparison to EBT3, EBT-XD gave improved evaluation results for the SRS-plan, had improved calibration curve gradients at high doses, and had reduced lateral scanner effect. The dimensions of the two films are identical. The optical density of EBT-XD is lower than EBT3 for the same dose. The effective atomic number for both may be considered water-equivalent in MV radiotherapy. We have validated the use of EBT-XD for high-dose, small-field radiotherapy, for routine QC and a forthcoming multi-centre SRS dosimetry intercomparison. (paper)

Dosimetry and operation of irradiation facilities

International Nuclear Information System (INIS)

Vidal, P.E.

1985-01-01

The industrial use of ionizing radiation has required, from the very first, the measurement of delivered and absorbed doses; hence the necessity of providing dosimetric systems. Laboratories, scientists, industries and potential equipment manufacturers have all collaborated in this new field of activity. Dosimetric intercomparisons have been made by each industry at their own facilities and in collaboration with specialists, national organizations and the IAEA. Dosimetry has become a way of ensuring that treatment by irradiation has been carried out in accordance with the rules. It has become in effect assurance of quality. Routine dosimetry should determine a maximum and minimum dose. Numerous factors play a part in dosimetry. Industry is currently in possession of routine dosimetric systems that are sufficiently accurate, fairly easy to handle and reasonable in cost, thereby satisfying all the requirements of industry and the need for control. Dosimetry is important in the process of marketing irradiated products. The operator of an industrial irradiation facility bases his dosimetry on comparison with reference systems. Research aimed at simplifying the practice of routine dosimetry should be continued. New physical and chemical techniques will be incorporated into systems already in use. The introduction of microcomputers into the operation of radiation facilities has increased the value of dosimetry and made the conditions of treatment more widespread. Stress should be placed on research in several areas apart from reference systems, for example: dosimetric systems at temperatures from +8 deg. C to -45 deg. C, over the dose range 100 krad to a little more than 1 Mrad, liquids and fluidized solids carried at high speed through ducts, thin-film liquids circulating at a high flow rate, and various other problems. (author)

Clinical application of a OneDose MOSFET for skin dose measurements during internal mammary chain irradiation with high dose rate brachytherapy in carcinoma of the breast.

Science.gov (United States)

Kinhikar, Rajesh A; Sharma, Pramod K; Tambe, Chandrashekhar M; Mahantshetty, Umesh M; Sarin, Rajiv; Deshpande, Deepak D; Shrivastava, Shyam K

2006-07-21

In our earlier study, we experimentally evaluated the characteristics of a newly designed metal oxide semiconductor field effect transistor (MOSFET) OneDose in-vivo dosimetry system for Ir-192 (380 keV) energy and the results were compared with thermoluminescent dosimeters (TLDs). We have now extended the same study to the clinical application of this MOSFET as an in-vivo dosimetry system. The MOSFET was used during high dose rate brachytherapy (HDRBT) of internal mammary chain (IMC) irradiation for a carcinoma of the breast. The aim of this study was to measure the skin dose during IMC irradiation with a MOSFET and a TLD and compare it with the calculated dose with a treatment planning system (TPS). The skin dose was measured for ten patients. All the patients' treatment was planned on a PLATO treatment planning system. TLD measurements were performed to compare the accuracy of the measured results from the MOSFET. The mean doses measured with the MOSFET and the TLD were identical (0.5392 Gy, 15.85% of the prescribed dose). The mean dose was overestimated by the TPS and was 0.5923 Gy (17.42% of the prescribed dose). The TPS overestimated the skin dose by 9% as verified by the MOSFET and TLD. The MOSFET provides adequate in-vivo dosimetry for HDRBT. Immediate readout after irradiation, small size, permanent storage of dose and ease of use make the MOSFET a viable alternative for TLDs.

On the impact of improved dosimetric accuracy on head and neck high dose rate brachytherapy.

Science.gov (United States)

Peppa, Vasiliki; Pappas, Eleftherios; Major, Tibor; Takácsi-Nagy, Zoltán; Pantelis, Evaggelos; Papagiannis, Panagiotis

2016-07-01

To study the effect of finite patient dimensions and tissue heterogeneities in head and neck high dose rate brachytherapy. The current practice of TG-43 dosimetry was compared to patient specific dosimetry obtained using Monte Carlo simulation for a sample of 22 patient plans. The dose distributions were compared in terms of percentage dose differences as well as differences in dose volume histogram and radiobiological indices for the target and organs at risk (mandible, parotids, skin, and spinal cord). Noticeable percentage differences exist between TG-43 and patient specific dosimetry, mainly at low dose points. Expressed as fractions of the planning aim dose, percentage differences are within 2% with a general TG-43 overestimation except for the spine. These differences are consistent resulting in statistically significant differences of dose volume histogram and radiobiology indices. Absolute differences of these indices are however small to warrant clinical importance in terms of tumor control or complication probabilities. The introduction of dosimetry methods characterized by improved accuracy is a valuable advancement. It does not appear however to influence dose prescription or call for amendment of clinical recommendations for the mobile tongue, base of tongue, and floor of mouth patient cohort of this study. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

Development of new methodology for dose calculation in photographic dosimetry

International Nuclear Information System (INIS)

Daltro, T.F.L.

1994-01-01

A new methodology for equivalent dose calculations has been developed at IPEN-CNEN/SP to be applied at the Photographic Dosimetry Laboratory using artificial intelligence techniques by means of neutral network. The research was orientated towards the optimization of the whole set of parameters involves in the film processing going from the irradiation in order to obtain the calibration curve up to the optical density readings. The learning of the neutral network was performed by taking the readings of optical density from calibration curve as input and the effective energy and equivalent dose as output. The obtained results in the intercomparison show an excellent agreement with the actual values of dose and energy given by the National Metrology Laboratory of Ionizing Radiation. (author)

Development of new methodology for dose calculation in photographic dosimetry

International Nuclear Information System (INIS)

Daltro, T.F.L.; Campos, L.L.

1994-01-01

A new methodology for equivalent dose calculation has been developed at IPEN-CNEN/SP to be applied at the Photographic Dosimetry Laboratory using artificial intelligence techniques by means of neural network. The research was oriented towards the optimization of the whole set of parameters involved in the film processing going from the irradiation in order to obtain the calibration curve up to the optical density readings. The learning of the neural network was performed by taking readings of optical density from calibration curve as input and the effective energy and equivalent dose as output. The obtained results in the intercomparison show an excellent agreement with the actual values of dose and energy given by the National Metrology Laboratory of Ionizing Radiation

The Third International Intercomparison on EPR Tooth Dosimetry: Part 2, final analysis

International Nuclear Information System (INIS)

Wieser, A.; Debuyst, R.; Fattibene, P.; Meghzifene, A.; Onori, S.; Bayankin, S. N.; Brik, A.; Bugay, A.; Chumak, V.; Ciesielski, B.; Hoshi, M.; Imata, H.; Ivannikov, A.; Ivanov, D.; Junczewska, M.; Miyazawa, C.; Penkowski, M.; Pivovarov, S.; Romanyukha, A.; Romanyukha, L.; Schauer, D.; Scherbina, O.; Schultka, K.; Sholom, S.; Skvortsov, V.; Stepanenko, V.; Thomas, J. A.; Tielewuhan, E.; Toyoda, S.; Trompier, F.

2006-01-01

The objective of the Third International Intercomparison on EPR Tooth Dosimetry was to evaluate laboratories performing tooth enamel dosimetry <300 mGy. Final analysis of results included a correlation analysis between features of laboratory dose reconstruction protocols and dosimetry performance. Applicability of electron paramagnetic resonance (EPR) tooth dosimetry at low dose was shown at two applied dose levels of 79 and 176 mGy. Most (9 of 12) laboratories reported the dose to be within 50 mGy of the delivered dose of 79 mGy, and 10 of 12 laboratories reported the dose to be within 100 mGy of the delivered dose of 176 mGy. At the high-dose tested (704 mGy) agreement within 25% of the delivered dose was found in 10 laboratories. Features of EPR dose reconstruction protocols that affect dosimetry performance were found to be magnetic field modulation amplitude in EPR spectrum recording, EPR signal model in spectrum deconvolution and duration of latency period for tooth enamel samples after preparation. (authors)

In vivo dosimetry using a linear Mosfet-array dosimeter to determine the urethra dose in 125I permanent prostate implants.

Science.gov (United States)

Bloemen-van Gurp, Esther J; Murrer, Lars H P; Haanstra, Björk K C; van Gils, Francis C J M; Dekker, Andre L A J; Mijnheer, Ben J; Lambin, Philippe

2009-01-01

In vivo dosimetry during brachytherapy of the prostate with (125)I seeds is challenging because of the high dose gradients and low photon energies involved. We present the results of a study using metal-oxide-semiconductor field-effect transistor (MOSFET) dosimeters to evaluate the dose in the urethra after a permanent prostate implantation procedure. Phantom measurements were made to validate the measurement technique, determine the measurement accuracy, and define action levels for clinical measurements. Patient measurements were performed with a MOSFET array in the urinary catheter immediately after the implantation procedure. A CT scan was performed, and dose values, calculated by the treatment planning system, were compared to in vivo dose values measured with MOSFET dosimeters. Corrections for temperature dependence of the MOSFET array response and photon attenuation in the catheter on the in vivo dose values are necessary. The overall uncertainty in the measurement procedure, determined in a simulation experiment, is 8.0% (1 SD). In vivo dose values were obtained for 17 patients. In the high-dose region (> 100 Gy), calculated and measured dose values agreed within 1.7% +/- 10.7% (1 SD). In the low-dose region outside the prostate (MOSFET detectors are suitable for in vivo dosimetry during (125)I brachytherapy of prostate cancer. An action level of +/- 16% (2 SD) for detection of errors in the implantation procedure is achievable after validation of the detector system and measurement conditions.

Field dosimetry on sterilization area of medical-hospitable materials

International Nuclear Information System (INIS)

Mariano, C.S.T.P.; Campos, L.L.

1992-01-01

The calcium sulfate doped with dysprosium, used in high dose dosimetry by electron paramagnetic resonance (EPR), is studied on field dosimetry for medical-hospitable materials sterilization. The calibration curves of EPR signal in function of absorbed dose in air and the thermal decay of EPR signal at room temperature are also presented. (C.G.C)

NIST high-dose calibration services

International Nuclear Information System (INIS)

Humphreys, J.C.

1989-01-01

There is a need for the standardization of high-dose measurements used in the radiation-processing industry in order to provide assured traceability to national standards. NIST provides dosimetry calibration services to this industry. One of these services involves administration of known absorbed doses of gamma rays to customer-supplied dosimeters. The dosimeters are packaged to provide electron equilibrium conditions and are irradiated in a standard 60 Co calibration facility; this provides a calibration of that batch of dosimeters. Another service consists of supplying to a customer calibrated transfer dosimeters for irradiation with the customer's radiation source. The irradiated transfer dosimeters are then returned to NIST for analysis; the results are reported to the customer, providing a calibration of the dose rate of the customer's source. (orig.)

Application of an alanine dosimetry system for industrial irradiation and radiation protection

International Nuclear Information System (INIS)

Gohs, U.

1996-01-01

This paper reports the application of alanine dosimetry in radiation processing. Continuous checks of the EPR measuring conditions as well as using high-quality alanine dosimeters and consistent technique for dose determination guarantee an accuracy of about ± 3% intermediate dose levels. The alanine dosimetry system was applied for dose mapping measurements during irradiator qualification and performance qualification of different products, routine dosimetry, and special radiation protection applications within the gamma irradiator. (author)

Improvement of dose determination using glass display of mobile phones for accident dosimetry

International Nuclear Information System (INIS)

Discher, M.; Woda, C.; Fiedler, I.

2013-01-01

Previous studies have demonstrated that mobile phones can be used as suitable emergency dosimeters in case of an accidental radiation overexposure. Glass samples extracted from displays of mobile phones are sensitive to ionizing radiation and can be measured using the thermoluminescence (TL) method. A non-radiation induced background signal (so-called zero dose signal) was observed which overlaps with the radiation induced signal and consequently limits the minimum detectable dose. Investigations of several glasses from different displays showed that it is possible to reduce the zero dose signal up to 90% by etching the glass surface with concentrated hydrofluoric acid. With this approach a reduction of the detection limit of a factor of four, corresponding to approximately 80 mGy, was achieved. Dosimetric properties of etched samples are presented and developed protocols validated by dose recovery tests under realistic conditions. With the improvements in sample preparation the proposed method of dose determination is a competitive alternative to OSL/TL measurements of electronic components and chip cards and provides a useful option for retrospective accident dosimetry. -- Highlights: ► Glass displays from mobile phones have good potential for emergency dosimetry. ► The background signal can be reduced by etching glass samples with hydrofluoric acid. ► The minimum detectable dose can be lowered to approximately 80 mGy

Postimplant Dosimetry Using a Monte Carlo Dose Calculation Engine: A New Clinical Standard

International Nuclear Information System (INIS)

Carrier, Jean-Francois; D'Amours, Michel; Verhaegen, Frank; Reniers, Brigitte; Martin, Andre-Guy; Vigneault, Eric; Beaulieu, Luc

2007-01-01

Purpose: To use the Monte Carlo (MC) method as a dose calculation engine for postimplant dosimetry. To compare the results with clinically approved data for a sample of 28 patients. Two effects not taken into account by the clinical calculation, interseed attenuation and tissue composition, are being specifically investigated. Methods and Materials: An automated MC program was developed. The dose distributions were calculated for the target volume and organs at risk (OAR) for 28 patients. Additional MC techniques were developed to focus specifically on the interseed attenuation and tissue effects. Results: For the clinical target volume (CTV) D 90 parameter, the mean difference between the clinical technique and the complete MC method is 10.7 Gy, with cases reaching up to 17 Gy. For all cases, the clinical technique overestimates the deposited dose in the CTV. This overestimation is mainly from a combination of two effects: the interseed attenuation (average, 6.8 Gy) and tissue composition (average, 4.1 Gy). The deposited dose in the OARs is also overestimated in the clinical calculation. Conclusions: The clinical technique systematically overestimates the deposited dose in the prostate and in the OARs. To reduce this systematic inaccuracy, the MC method should be considered in establishing a new standard for clinical postimplant dosimetry and dose-outcome studies in a near future

Dosimetry quality audit of high energy photon beams in greek radiotherapy centers

International Nuclear Information System (INIS)

Hourdakis, Constantine J.; Boziari, A.

2008-01-01

Background and purpose: Dosimetry quality audits and intercomparisons in radiotherapy centers is a useful tool in order to enhance the confidence for an accurate therapy and to explore and dissolve discrepancies in dose delivery. This is the first national comprehensive study that has been carried out in Greece. During 2002 - 2006 the Greek Atomic Energy Commission performed a dosimetry quality audit of high energy external photon beams in all (23) Greek radiotherapy centers, where 31 linacs and 13 Co-60 teletherapy units were assessed in terms of their mechanical performance characteristics and relative and absolute dosimetry. Materials and Methods: The quality audit in dosimetry of external photon beams took place by means of on-site visits, where certain parameters of the photon beams were measured, calculated and assessed according to a specific protocol and the IAEA TRS 398 dosimetry code of practice. In each radiotherapy unit (Linac or Co-60), certain functional parameters were measured and the results were compared to tolerance values and limits. Doses in water under reference and non reference conditions were measured and compared to the stated values. Also, the treatment planning systems (TPS) were evaluated with respect to irradiation time calculations. Results: The results of the mechanical tests, dosimetry measurements and TPS evaluation have been presented in this work and discussed in detail. This study showed that Co-60 units had worse performance mechanical characteristics than linacs. 28% of all irradiation units (23% of linacs and 42% of Co-60 units) exceeded the acceptance limit at least in one mechanical parameter. Dosimetry accuracy was much worse in Co60 units than in linacs. 61% of the Co60 units exhibited deviations outside ±3% and 31% outside ±5%. The relevant percentages for the linacs were 24% and 7% respectively. The results were grouped for each hospital and the sources of errors (functional and human) have been investigated and

Dosimetry quality audit of high energy photon beams in greek radiotherapy centers.

Science.gov (United States)

Hourdakis, Constantine J; Boziari, A

2008-04-01

Dosimetry quality audits and intercomparisons in radiotherapy centers is a useful tool in order to enhance the confidence for an accurate therapy and to explore and dissolve discrepancies in dose delivery. This is the first national comprehensive study that has been carried out in Greece. During 2002--2006 the Greek Atomic Energy Commission performed a dosimetry quality audit of high energy external photon beams in all (23) Greek radiotherapy centers, where 31 linacs and 13 Co-60 teletherapy units were assessed in terms of their mechanical performance characteristics and relative and absolute dosimetry. The quality audit in dosimetry of external photon beams took place by means of on-site visits, where certain parameters of the photon beams were measured, calculated and assessed according to a specific protocol and the IAEA TRS 398 dosimetry code of practice. In each radiotherapy unit (Linac or Co-60), certain functional parameters were measured and the results were compared to tolerance values and limits. Doses in water under reference and non reference conditions were measured and compared to the stated values. Also, the treatment planning systems (TPS) were evaluated with respect to irradiation time calculations. The results of the mechanical tests, dosimetry measurements and TPS evaluation have been presented in this work and discussed in detail. This study showed that Co-60 units had worse performance mechanical characteristics than linacs. 28% of all irradiation units (23% of linacs and 42% of Co-60 units) exceeded the acceptance limit at least in one mechanical parameter. Dosimetry accuracy was much worse in Co60 units than in linacs. 61% of the Co60 units exhibited deviations outside +/-3% and 31% outside +/-5%. The relevant percentages for the linacs were 24% and 7% respectively. The results were grouped for each hospital and the sources of errors (functional and human) have been investigated and discussed in details. This quality audit proved to be a

Clinical application of a OneDose(TM) MOSFET for skin dose measurements during internal mammary chain irradiation with high dose rate brachytherapy in carcinoma of the breast

International Nuclear Information System (INIS)

Kinhikar, Rajesh A; Sharma, Pramod K; Tambe, Chandrashekhar M; Mahantshetty, Umesh M; Sarin, Rajiv; Deshpande, Deepak D; Shrivastava, Shyam K

2006-01-01

In our earlier study, we experimentally evaluated the characteristics of a newly designed metal oxide semiconductor field effect transistor (MOSFET) OneDose(TM) in-vivo dosimetry system for Ir-192 (380 keV) energy and the results were compared with thermoluminescent dosimeters (TLDs). We have now extended the same study to the clinical application of this MOSFET as an in-vivo dosimetry system. The MOSFET was used during high dose rate brachytherapy (HDRBT) of internal mammary chain (IMC) irradiation for a carcinoma of the breast. The aim of this study was to measure the skin dose during IMC irradiation with a MOSFET and a TLD and compare it with the calculated dose with a treatment planning system (TPS). The skin dose was measured for ten patients. All the patients' treatment was planned on a PLATO treatment planning system. TLD measurements were performed to compare the accuracy of the measured results from the MOSFET. The mean doses measured with the MOSFET and the TLD were identical (0.5392 Gy, 15.85% of the prescribed dose). The mean dose was overestimated by the TPS and was 0.5923 Gy (17.42% of the prescribed dose). The TPS overestimated the skin dose by 9% as verified by the MOSFET and TLD. The MOSFET provides adequate in-vivo dosimetry for HDRBT. Immediate readout after irradiation, small size, permanent storage of dose and ease of use make the MOSFET a viable alternative for TLDs. (note)

Lithium formate EPR dosimetry for verifications of planned dose distributions prior to intensity-modulated radiation therapy

Science.gov (United States)

Gustafsson, H.; Lund, E.; Olsson, S.

2008-09-01

The objective of the present investigation was to evaluate lithium formate electron paramagnetic resonance (EPR) dosimetry for measurement of dose distributions in phantoms prior to intensity-modulated radiation therapy (IMRT). Lithium formate monohydrate tablets were carefully prepared, and blind tests were performed in clinically relevant situations in order to determine the precision and accuracy of the method. Further experiments confirmed that within the accuracy of the current method, the dosimeter response was independent of beam energies and dose rates used for IMRT treatments. The method was applied to IMRT treatment plans, and the dose determinations were compared to ionization chamber measurements. The experiments showed that absorbed doses above 3 Gy could be measured with an uncertainty of less than 2.5% of the dose (coverage factor k = 1.96). Measurement time was about 15 min using a well-calibrated dosimeter batch. The conclusion drawn from the investigation was that lithium formate EPR dosimetry is a promising new tool for absorbed dose measurements in external beam radiation therapy, especially for doses above 3 Gy.

Lithium formate EPR dosimetry for verifications of planned dose distributions prior to intensity-modulated radiation therapy

Energy Technology Data Exchange (ETDEWEB)

Gustafsson, H; Lund, E [Department of Medical and Health Sciences, Radiation Physics, Faculty of Health Sciences, Linkoeping University, S-581 85 Linkoeping (Sweden); Olsson, S [Division of Radiation Physics, Linkoeping University Hospital, S-581 85 Linkoeping (Sweden)], E-mail: hakgu@imv.liu.se

2008-09-07

The objective of the present investigation was to evaluate lithium formate electron paramagnetic resonance (EPR) dosimetry for measurement of dose distributions in phantoms prior to intensity-modulated radiation therapy (IMRT). Lithium formate monohydrate tablets were carefully prepared, and blind tests were performed in clinically relevant situations in order to determine the precision and accuracy of the method. Further experiments confirmed that within the accuracy of the current method, the dosimeter response was independent of beam energies and dose rates used for IMRT treatments. The method was applied to IMRT treatment plans, and the dose determinations were compared to ionization chamber measurements. The experiments showed that absorbed doses above 3 Gy could be measured with an uncertainty of less than 2.5% of the dose (coverage factor k = 1.96). Measurement time was about 15 min using a well-calibrated dosimeter batch. The conclusion drawn from the investigation was that lithium formate EPR dosimetry is a promising new tool for absorbed dose measurements in external beam radiation therapy, especially for doses above 3 Gy.

Report on high energy neutron dosimetry workshop

International Nuclear Information System (INIS)

Alvar, K.R.; Gavron, A.

1993-01-01

The workshop was called to assess the performance of neutron dosimetry per the responses from ten DOE accelerator facilities to an Office of Energy Research questionnaire regarding implementation of a personnel dosimetry requirement in DRAFT DOE 5480.ACC, ''Safety of Accelerator Facilities''. The goals of the workshop were to assess the state of dosimetry at high energy accelerators and if such dosimetry requires improvement, to reach consensus on how to proceed with such improvements. There were 22 attendees, from DOE Programs and contract facilities, DOE, Office of Energy Research (ER), Office of Environmental Safety and Health (EH), Office of Fusion Energy, and the DOE high energy accelerator facilities. A list of attendees and the meeting agenda are attached. Copies of the presentations are also attached

Usefulness and problems of film dosimetry in high energy radiotherapy

International Nuclear Information System (INIS)

Hirabayashi, Hisae

1995-01-01

Film dosimetry is a convenient and quick method of obtaining a set of high energy radiation isodose curves in the plane of the film, but it is an empirical method which presents some problems. Many authors have reported on film dosimetry for industrial films. Recently, the development of computerized densitometer systems, ready-pack films for radiotherapy and automatic film processors has helped improve the procedure. This paper reports our experiences regarding film dosimetry using the new materials, its usefulness in radiotherapy and some of technical problems encountered. The optical density value corresponding to a given dose depends upon the processing conditions, for XV-2 film, variation is about 4% when an automatic processor is used under controlled conditions. The Off-axis-ratios and the PDD in the perpendicular film plane agree well with the ion-chamber for photon and electron beams; by contrast, the PDD in the parallel film plane is significantly affected by variations in the phantom thickness, the type of film package and misalignment in phantom. But, bare films inserted into a cassette made of phantom material agree well for electron beams. Film dosimetry is effective and accurate at the edges of the field and for small fields, due to its high spatial resolution and rapid method. In addition, it is useful for electron beams OCR beam data input; for evaluating the input parameters for treatment planning systems; for quality assurance of the treatment equipment; and for preliminary clinical studies. Even when modern materials are used for film dosimetry, some technical problems will arise. Thus, to ensure the accuracy, certain precautions are required when setting conditions of film exposure and for quality control of the film processor. (author)

On the absorbed dose determination method in high energy photon beams

International Nuclear Information System (INIS)

Scarlat, F.; Scarisoreanu, A.; Oane, M.; Mitru, E.; Avadanei, C.

2008-01-01

The absorbed dose determination method in water, based on standards of air kerma or exposure in high energy photon beams generated by electron with energies in the range of 1 MeV to 50 MeV is presented herein. The method is based on IAEA-398, AAPM TG-51, DIN 6800-2, IAEA-381, IAEA-277 and NACP-80 recommendations. The dosimetry equipment is composed of UNIDOS T 10005 electrometer and different ionization chambers calibrated in air kerma method in a Co 60 beam. Starting from the general formalism showed in IAEA-381, the determination of absorbed dose in water, under reference conditions in high energy photon beams, is given. This method was adopted for the secondary standard dosimetry laboratory (SSDL) in NILPRP-Bucharest

Dosimetry optimization at COGEMA-La Hague

International Nuclear Information System (INIS)

Kalimbadjian, J.

2000-01-01

At the present time, the la Hague site strives to apply international recommendations together with national regulations concerning radiation protection, and especially the respect of limitation and optimization principles. The application of these principles is based on the implementation of a passive dosimetry and an active dosimetry. The monthly passive dosimetry is monitored by means of a photographic dosimetry film, completed with lithium fluorine thermoluminescent film badges. This personal dosimetry common to X, β, γ and neutron radiations is carried out in close relationship between the Radiation Protection Department, the Occupational Medical Department and the staff running the Plant. The application or ALARA's principle as well as that of radiation protection optimization implies to implement a complementary active dosimetry enabling to gain in real time, the personal dosimetry of each intervening person, either they be COGEMA's workers or external companies'. This active dosimetry provides with following information: This preventive dosimetry is based on the knowledge of doses integration in real time and is fitted with alarm thresholds according to the total amount of doses and dose rates. Thresholds on the dose rate are also set relatively to the radiological environment. This knowledge of doses and dose rates allows a stricter management of the works, while analyzing them according to the nature of the work, to the location and to the skills of the intervening people. This dosimetry allows to analyze and optimize doses integration according to the works nature for the whole intervening staff. The la Hague Site has developed an active personal dosimetry system, common to every intervening person, COGEMA or external companies. The DOSICARD was thus elaborated, shaped as an electronic dosimeter fitted with an alarm and a smart card. The access to controlled areas is conditioned to information given by the DOSICARD concerning medical aptitudes and

Do we need 3D tube current modulation information for accurate organ dosimetry in chest CT? Protocols dose comparisons.

Science.gov (United States)

Lopez-Rendon, Xochitl; Zhang, Guozhi; Coudyzer, Walter; Develter, Wim; Bosmans, Hilde; Zanca, Federica

2017-11-01

To compare the lung and breast dose associated with three chest protocols: standard, organ-based tube current modulation (OBTCM) and fast-speed scanning; and to estimate the error associated with organ dose when modelling the longitudinal (z-) TCM versus the 3D-TCM in Monte Carlo simulations (MC) for these three protocols. Five adult and three paediatric cadavers with different BMI were scanned. The CTDI vol of the OBTCM and the fast-speed protocols were matched to the patient-specific CTDI vol of the standard protocol. Lung and breast doses were estimated using MC with both z- and 3D-TCM simulated and compared between protocols. The fast-speed scanning protocol delivered the highest doses. A slight reduction for breast dose (up to 5.1%) was observed for two of the three female cadavers with the OBTCM in comparison to the standard. For both adult and paediatric, the implementation of the z-TCM data only for organ dose estimation resulted in 10.0% accuracy for the standard and fast-speed protocols, while relative dose differences were up to 15.3% for the OBTCM protocol. At identical CTDI vol values, the standard protocol delivered the lowest overall doses. Only for the OBTCM protocol is the 3D-TCM needed if an accurate (<10.0%) organ dosimetry is desired. • The z-TCM information is sufficient for accurate dosimetry for standard protocols. • The z-TCM information is sufficient for accurate dosimetry for fast-speed scanning protocols. • For organ-based TCM schemes, the 3D-TCM information is necessary for accurate dosimetry. • At identical CTDI vol , the fast-speed scanning protocol delivered the highest doses. • Lung dose was higher in XCare than standard protocol at identical CTDI vol .

Status of radiation dosimetry in Germany using ionization chamber calibrated in terms of absorbed dose to water

International Nuclear Information System (INIS)

Hohlfeld, Klaus; Roos, Martin

1995-01-01

In 1984 the PTB as PSDL and the DIN Standard Committee on Radiology (NAR) in close co-operation decided that in Germany the measured absorbed dose to water in a water phantom should replace exposure in the dosimetry for radiation therapy. The PTB has established primary standards of water absorbed dose in the whole range of photon and electron radiation, and international comparisons at the BIPM and with other PSDLs proved agreement within 0.5%. Secondary standards are calibrated in a water phantom under reference conditions in a Co-60 gamma radiation beam at the PTB. Thus, the calibration factor in terms of water absorbed dose, N W , is transferred to the manufacturers of dosimeters, the German Calibration Service and the dosimetry laboratories of the verification authorities. The Verification Law subjects each ionization dosimeter used in the treatment of patients with external photon radiation beams under a type-test at PTB and under a verification procedure, where the calibration factor, N W , must be shown to be within given limits. The absorbed dose determination at the users' level follows the foralism prescribed in the Standard DIN 6800-2 (1995) 'Procedures for Absorbed Dose Determination in Radiology by the Ionization Method'. The concept of this DIN Standard uses exclusively one quantity from the primary standard to the user's instrument eliminating uncertainties and sources of mistakes associated with the conversion of a calibration factor. The concept is simple and clear and covers the whole range of photon and electron radiation. As a means of quality assurance in basic dosimetry the PTB runs a calibration service, up to now on a voluntary basis, which allows the user to compare his dosimetry system against PTB standards using mailed Fricke ampoules, with water absorbed dose as measured and used

Implications of radiation risk for practical dosimetry

International Nuclear Information System (INIS)

Dennis, J.A.

1984-01-01

Radiobiological experiments with animals and cells have led to an expectation that the risks of cancer and hereditary effects are reduced at low doses and low dose rates of low LET radiation. Risk estimates derived from human exposures at high doses and dose rates usually contain an allowance for low dose effects in comparison with high dose effects, but no allowance may have been made for low dose rate effects. Although there are reasons for thinking that leukaemia risks may possibly have been underestimated, the total cancer risk assumed by ICRP for occupational exposures is reasonably realistic. For practical dosimetry the primary dose concepts and limits have to be translated into secondary quantities that are capable of practical realisation and measurement, and which will provide a stable and robust system of metrology. If the ICRP risk assumptions are approximately correct, it is extremely unlikely that epidemiological studies of occupational exposures will detect the influence of radiation. Elaboration of dosimetry and dose recording for epidemiological purposes is therefore unjustified except possibly in relation to differences between high and low LET radiations. (author)

Dosimetry systems for radiation processing

International Nuclear Information System (INIS)

McLaughlin, W.L.; Desrosiers, M.F.

1995-01-01

Dosimetry serves important functions in radiation processing, where large absorbed doses and dose rates from photon and electron sources have to be measured with reasonable accuracy. Proven dosimetry systems are widely used to perform radiation measurements in development of new processes, validation, qualification and verification (quality control) of established processes and archival documentation of day-to-day and plant-to-plant processing uniformity. Proper calibration and traceability of routine dosimetry systems to standards are crucial to the success of many large-volume radiation processes. Recent innovations and advances in performance of systems that enhance radiation measurement assurance and process diagnostics include dose-mapping media (new radiochromic film and solutions), optical waveguide systems for food irradiation, solid-state devices for real-time and passive dosimetry over wide dose-rate and dose ranges, and improved analytical instruments and data acquisition. (author)

Application of monomer/polymer gel dosimetry to study the effects of tissue inhomogeneities on intensity-modulated radiation therapy (IMRT) dose distributions.

Science.gov (United States)

Vergote, Koen; De Deene, Yves; Claus, Filip; De Gersem, Werner; Van Duyse, Bart; Paelinck, Leen; Achten, Eric; De Neve, Wilfried; De Wagter, Carlos

2003-04-01

When planning an intensity-modulated radiation therapy (IMRT) treatment in a heterogeneous region (e.g. the thorax), the dose computation algorithm of a treatment planning system may need to account for these inhomogeneities in order to obtain a reliable prediction of the dose distribution. An accurate dose verification technique such as monomer/polymer gel dosimetry is suggested to verify the outcome of the planning system. The effects of low-density structures: (a) on narrow high-energy (18 MV) photon beams; and (b) on a class-solution IMRT treatment delivered to a thorax phantom have been examined using gel dosimetry. The used phantom contained air cavities that could be filled with water to simulate a homogeneous or heterogeneous configuration. The IMRT treatment for centrally located lung tumors was delivered on both cases, and gel derived dose maps were compared with computations by both the GRATIS and Helax-TMS planning system. Dose rebuildup due to electronic disequilibrium in a narrow photon beam is demonstrated. The gel measurements showed good agreement with diamond detector measurements. Agreement between measured IMRT dose maps and dose computations was demonstrated by several quantitative techniques. An underdosage of the planning target volume (PTV) was revealed. The homogeneity of the phantom had only a minor influence on the dose distribution in the PTV. An expansion of low-level isodoses in the lung volume was predicted by collapsed cone computations in the heterogeneous case. For the class-solution described, the dose in centrally located mediastinal tumors can be computed with sufficient accuracy, even when neglecting the lower lung density. Polymer gel dosimetry proved to be a valuable technique to verify dose calculation algorithms for IMRT in 3D in heterogeneous configurations.

Gamma irradiator dose mapping simulation using the MCNP code and benchmarking with dosimetry

International Nuclear Information System (INIS)

Sohrabpour, M.; Hassanzadeh, M.; Shahriari, M.; Sharifzadeh, M.

2002-01-01

The Monte Carlo transport code, MCNP, has been applied in simulating dose rate distribution in the IR-136 gamma irradiator system. Isodose curves, cumulative dose values, and system design data such as throughputs, over-dose-ratios, and efficiencies have been simulated as functions of product density. Simulated isodose curves, and cumulative dose values were compared with dosimetry values obtained using polymethyle-methacrylate, Fricke, ethanol-chlorobenzene, and potassium dichromate dosimeters. The produced system design data were also found to agree quite favorably with those of the system manufacturer's data. MCNP has thus been found to be an effective transport code for handling of various dose mapping excercises for gamma irradiators

Optimized dose distribution of a high dose rate vaginal cylinder

International Nuclear Information System (INIS)

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

1998-01-01

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

Assessments for high dose radionuclide therapy treatment planning

International Nuclear Information System (INIS)

Fisher, D.R.

2003-01-01

Advances in the biotechnology of cell specific targeting of cancer and the increased number of clinical trials involving treatment of cancer patients with radiolabelled antibodies, peptides, and similar delivery vehicles have led to an increase in the number of high dose radionuclide therapy procedures. Optimised radionuclide therapy for cancer treatment is based on the concept of absorbed dose to the dose limiting normal organ or tissue. The limiting normal tissue is often the red marrow, but it may sometimes be the lungs, liver, intestinal tract, or kidneys. Appropriate treatment planning requires assessment of radiation dose to several internal organs and tissues, and usually involves biodistribution studies in the patient using a tracer amount of radionuclide bound to the targeting agent and imaged at sequential timepoints using a planar gamma camera. Time-activity curves are developed from the imaging data for the major organ tissues of concern, for the whole body and sometimes for selected tumours. Patient specific factors often require that dose estimates be customised for each patient. In the United States, the Food and Drug Administration regulates the experimental use of investigational new drugs and requires 'reasonable calculation of radiation absorbed dose to the whole body and to critical organs' using the methods prescribed by the Medical Internal Radiation Dose (MIRD) Committee of the Society of Nuclear Medicine. Review of high dose studies shows that some are conducted with minimal dosimetry, that the marrow dose is difficult to establish and is subject to large uncertainties. Despite the general availability of software, internal dosimetry methods often seem to be inconsistent from one clinical centre to another. (author)

Audits in high dose rate brachytherapy in Brazil

International Nuclear Information System (INIS)

Marechal, M.H.; Rosa, L.A.; Velasco, A.; Paiva, E. de; Goncalves, M.; Castelo, L.C.

2002-01-01

The lack of well established dosimetry protocols for HDR sources is a point of great concern regarding the uniformity of procedures within a particular country. The main objective of this paper is to report the results of an implementation of the audit program in dosimetry of high dose rate brachytherapy sources used by the radiation therapy centers in Brazil. In Brazil, among 169 radiotherapy centers, 35 have HDR brachytherapy systems. This program started in August 2001 and until now eight radiotherapy services were audited. The audit program consists of the visit in loco to each center and the evaluation of the intensity of the source with a well type chamber specially design for HDR 192 Ir sources. The measurements was carried out with a HDR1000PLUS Brachytherapy Well Type Chamber and a MAX 4000 Electrometer, both manufactured by Standard Imaging Inc. The chamber was calibrated in air kerma strength by the Accredited Dosimetry Calibration Laboratory, Department of Medical Physics, University of Wisconsin in the USA. The same chamber was calibrated in Brazil using a 192 lr high dose rate source whose intensity was determined by 60 Co gamma rays and 250 kV x rays interpolation methodology. The Nk of 60 Co and 250 kV x rays were provided by the Brazilian National Standard Laboratory for Ionizing Radiation (LMNRI)

Foundations of ionizing radiation dosimetry

International Nuclear Information System (INIS)

Denisenko, O.N.; Pereslegin, I.A.

1985-01-01

Foundations of dosimetry in application to radiotherapy are presented. General characteristics of ionizing radiations and main characteristics of ionizing radiation sources, mostly used in radiotherapy, are given. Values and units for measuring ionizing radiation (activity of a radioactive substance, absorbed dose, exposure dose, integral dose and dose equivalent are considered. Different methods and instruments for ionizing radiation dosimetry are discussed. The attention is paid to the foundations of clinical dosimetry (representation of anatomo-topographic information, choice of radiation conditions, realization of radiation methods, corrections for a configuration and inhomogeneity of a patient's body, account of biological factors of radiation effects, instruments of dose field formation, control of irradiation procedure chosen)

Biological dosimetry in radiological protection: dose response curves elaboration for 60Co and 137Cs

International Nuclear Information System (INIS)

Silva, Marcia Augusta da

1997-01-01

Ionizing radiation sources for pacific uses are being extensively utilized by modern society and the applications of these sources have raised the probability of the occurrence of accidents. The accidental exposition to radiation creates a necessity of the development of methods to evaluate dose quantity. This data could be obtained by the measurement of damage caused by radiation in the exposed person. The radiation dose can be estimated in exposed persons through physical methods (physical dosimetry) but the biological methods can't be dispensed, and among them, the cytogenetic one that makes use of chromosome aberrations (dicentric and centric ring) formed in peripheral blood lymphocytes (PBL) exposed to ionizing radiation. This method correlates the frequency of radioinduced aberrations with the estimated absorbed dose, as in vitro as in vivo, which is called cytogenetic dosimetry. By the introduction of improved new techniques in culture, in the interpretation of aberrations in the different analysers of slides and by the adoption of different statistical programs to analyse the data, significant differences are observed among laboratories in dose-response curves (calibration curves). The estimation of absorbed dose utilizing other laboratory calibration curves may introduce some uncertainties, so the International Atomic Energy Agency (IAEA) advises that each laboratory elaborates your own dose-response curve for cytogenetic dosimetry. The results were obtained from peripheral blood lymphocytes of the healthy and no-smoking donors exposed to 60 Co and 137 Cs radiation, with dose rate of 5 cGy.min. -1 . Six points of dose were determined 20,50,100,200,300,400 cGy and the control not irradiated. The analysed aberrations were of chromosomic type, dicentric and centric ring. The dose response curve for dicentrics were obtained by frequencies weighted in liner-quadratic mathematic model and the equation resulted were for 60 Co: Y = (3 46 +- 2.14)10 -4 cGy -1 + (3

Dosimetry during mango irradiation using Gafchromic HD-810 film

International Nuclear Information System (INIS)

Sharma, S. D.; Chilkulwar, R. H.; Kumar, R.

2009-01-01

The dosimetric characteristics of Gafchromic HD-810 film were evaluated for its possible use as a high-dose dosemeter for routine dosimetry during mango irradiation. The film dosemeter sample of size 2 x 2 cm 2 was used throughout the course of this work. The irradiation of the film dosemeter for characterisation and calibration purposes was carried out in a gamma irradiator. The dose-response of the Gafchromic HD-810 film dosemeter at 550 nm was found to be linear in the dose range 50-1000 Gy, which indicates the feasibility of using this film for dosimetry up to 1000 Gy. The mean inter-dosemeter variation was within 2%, which gives better dose-response consistency of the HD-810 film. The radiation absorbed dose measured by the Gafchromic HD-810 film dosemeter during mango irradiation was compared with that measured by a standard Ceric-cerous dosemeter. This study establishes the Gafchromic HD-810 film as a convenient and technically suitable dosemeter for high-dose dosimetry up to 1.0 kGy during mango irradiation. (authors)

High sensitivity MOSFET-based neutron dosimetry

International Nuclear Information System (INIS)

Fragopoulou, M.; Konstantakos, V.; Zamani, M.; Siskos, S.; Laopoulos, T.; Sarrabayrouse, G.

2010-01-01

A new dosemeter based on a metal-oxide-semiconductor field effect transistor sensitive to both neutrons and gamma radiation was manufactured at LAAS-CNRS Laboratory, Toulouse, France. In order to be used for neutron dosimetry, a thin film of lithium fluoride was deposited on the surface of the gate of the device. The characteristics of the dosemeter, such as the dependence of its response to neutron dose and dose rate, were investigated. The studied dosemeter was very sensitive to gamma rays compared to other dosemeters proposed in the literature. Its response in thermal neutrons was found to be much higher than in fast neutrons and gamma rays.

Dose measurements in dental radiology using thermoluminescent dosimetry;Medicoes de dose em radiodiagnostico odontologico utilizando dosimetria termoluminescente

Energy Technology Data Exchange (ETDEWEB)

Chiara, Ana Claudia M. de; Costa, Alessandro M. [Universidade de Sao Paulo (FFCLRP/USP), Ribeirao Preto, SP (Brazil). Faculdade de Filosofia, Ciencias e Letras; Pardini, Luiz Carlos [Universidade de Sao Paulo (FORP/USP), Ribeirao Preto, SP (Brazil). Faculdade de Odontologia

2009-07-01

The aim of this work was the implementation of a code of practice for dosimetry in dental radiology using the technique of thermoluminescent dosimetry. General principles for the use of thermoluminescent dosimeters were followed. The irradiations were performed using ten X-ray equipment for intra-oral radiography and an X-ray equipment for panoramic radiography. The incident air kerma was evaluated for five different exposure times used in clinical practice for intra-oral radiographs. Using a backscatter factor of 1.2, it was observed that approximately 40% of the entrance skin dose values found for intra-oral radiographs are above the diagnostic reference level recommended in national regulation. Different configurations of voltage and current were used representing the exposure as a child, woman and man for panoramic radiographs. The results obtained for the air kerma area product were respectively 53.3 +- 5.2 mGy.cm{sup 2}, 101.5 +- 9.5 mGy.cm{sup 2} and 116.8 +- 10.4 mGy.cm{sup 2}. The use of thermoluminescent dosimetry requires several procedures before a result is recorded. The use of dosimeters with ionization chambers or semiconductors provides a simple and robust method for routine measurements. However, the use of thermoluminescent dosimetry can be of great value to large-scale surveys to establish diagnostic reference levels. (author)

Photographic film dosimetry for high-energy accelerator radiation

International Nuclear Information System (INIS)

Komochkov, M.M.; Salatskaya, M.I.

1981-01-01

A technique for personnel photographic film dosimetry (PPFDN) of wide energy spectrum neutrons intended for measuring the effect of accelerating device radiation on personnel is described. Procedures of data measurement and processing as well as corrections to hadron contribution are presented. It is noted that the PPFDN method permits to measure a neutron dose equivalent for personnel in the range from 0.01 to 0.02 up to 100 rem, if the relativistic neutron contribution to a total dose does not exceed 5%. The upper limit of the measured dose reduced several times for a greater contribution of relativistic neutrons to the total dose [ru

Portal dosimetry in wedged beams

NARCIS (Netherlands)

Spreeuw, Hanno; Rozendaal, Roel; Camargo, Priscilla; Mans, Anton; Wendling, Markus; Olaciregui-Ruiz, Igor; Sonke, Jan-Jakob; van Herk, Marcel; Mijnheer, Ben

2015-01-01

Portal dosimetry using electronic portal imaging devices (EPIDs) is often applied to verify high-energy photon beam treatments. Due to the change in photon energy spectrum, the resulting dose values are, however, not very accurate in the case of wedged beams if the pixel-to-dose conversion for the

Dosimetry Service

CERN Multimedia

2006-01-01

Cern Staff and Users can now consult their dose records for an individual or an organizational unit with HRT. Please see more information on our web page: http://cern.ch/rp-dosimetry Dosimetry Service is open every morning from 8.30 - 12.00. Closed in the afternoons. We would like to remind you that dosimeters cannot be sent to customers by internal mail. Short-term dosimeters (VCT's) must always be returned to the Service after the use and must not be left on the racks in the experimental areas or in the secretariats. Dosimetry Service Tel. 7 2155 Dosimetry.service@cern.ch http://cern.ch/rp-dosimetry

Practical neutron dosimetry at high energies

International Nuclear Information System (INIS)

McCaslin, J.B.; Thomas, R.H.

1980-10-01

Dosimetry at high energy particle accelerators is discussed with emphasis on physical measurements which define the radiation environment and provide an immutable basis for the derivation of any quantities subsequently required for risk evaluation. Results of inter-laboratory dosimetric comparisons are reviewed and it is concluded that a well-supported systematic program is needed which would make possible detailed evaluations and inter-comparisons of instruments and techniques in well characterized high energy radiation fields. High-energy dosimetry is so coupled with radiation transport that it is clear their study should proceed concurrently

Neutron dosimetry in biology

International Nuclear Information System (INIS)

Sigurbjoernsson, B.; Smith, H.H.; Gustafsson, A.

1965-01-01

To study adequately the biological effects of different energy neutrons it is necessary to have high-intensity sources which are not contaminated by other radiations, the most serious of which are gamma rays. An effective dosimetry must provide an accurate measure of the absorbed dose, in biological materials, of each type of radiation at any reactor facility involved in radiobiological research. A standardized biological dosimetry, in addition to physical and chemical methods, may be desirable. The ideal data needed to achieve a fully documented dosimetry has been compiled by H. Glubrecht: (1) Energy spectrum and intensity of neutrons; (2) Angular distribution of neutrons on the whole surface of the irradiated object; (3) Additional undesired radiation accompanying the neutrons; (4) Physical state and chemical composition of the irradiated object. It is not sufficient to note only an integral dose value (e.g. in 'rad') as the biological effect depends on the above data

Neutron personnel dosimetry considerations for fusion reactors

International Nuclear Information System (INIS)

Barton, T.P.; Easterly, C.E.

1979-07-01

The increasing development of fusion reactor technology warrants an evaluation of personnel neutron dosimetry systems to aid in the concurrent development of a radiation protection program. For this reason, current state of knowledge neutron dosimeters have been reviewed with emphasis placed on practical utilization and the problems inherent in each type of dosimetry system. Evaluations of salient parameters such as energy response, latent image instability, and minimum detectable dose equivalent are presented for nuclear emulsion films, track etch techniques, albedo and other thermoluminescent dosimetry techniques, electrical conductivity damage effects, lyoluminescence, thermocurrent, and thermally stimulated exoelectron emission. Brief summaries of dosimetry regulatory requirements and intercomparison study results help to establish compliance and recent trends, respectively. Spectrum modeling data generated by the Neutron Physics Division of Oak Ridge National Laboratory for the Princeton Tokamak Fusion Test Reactor (TFTR) Facility have been analyzed by both International Commission on Radiological Protection fluence to dose conversion factors and an adjoint technique of radiation dosimetry, in an attempt to determine the applicability of current neutron dosimetry systems to deuterium and tritium fusion reactor leakage spectra. Based on the modeling data, a wide range of neutron energies will probably be present in the leakage spectra of the TFTR facility, and no appreciable risk of somatic injury to occupationally exposed workers is expected. The relative dose contributions due to high energy and thermal neutrons indicate that neutron dosimetry will probably not be a serious limitation in the development of fusion power

Intercomparison of personnel dosimetry for thermal neutron dose equivalent in neutron and gamma-ray mixed fields

International Nuclear Information System (INIS)

Ogawa, Yoshihiro

1985-01-01

In order to consider the problems concerned with personnel dosimetry using film badges and TLDs, an intercomparison of personnel dosimetry, especially dose equivalent responses of personnel dosimeters to thermal neutron, was carried out in five different neutron and gamma-ray mixed fields at KUR and UTR-KINKI from the practical point of view. For the estimation of thermal neutron dose equivalent, it may be concluded that each personnel dosimeter has good performances in the precision, that is, the standard deviations in the measured values by individual dosimeter were within 24 %, and the dose equivalent responses to thermal neutron were almost independent on cadmium ratio and gamma-ray contamination. However, the relative thermal neutron dose equivalent of individual dosimeter normalized to the ICRP recommended value varied considerably and a difference of about 4 times was observed among the dosimeters. From the results obtained, it is suggested that the standardization of calibration factors and procedures is required from the practical point of radiation protection and safety. (author)

On the absorbed dose determination method in high energy electrons beams

International Nuclear Information System (INIS)

Scarlat, F.; Scarisoreanu, A.; Oane, M.; Mitru, E.; Avadanei, C.

2008-01-01

The absorbed dose determination method in water for electron beams with energies in the range from 1 MeV to 50 MeV is presented herein. The dosimetry equipment for measurements is composed of an UNIDOS.PTW electrometer and different ionization chambers calibrated in air kerma in a Co 60 beam. Starting from the code of practice for high energy electron beams, this paper describes the method adopted by the secondary standard dosimetry laboratory (SSDL) in NILPRP - Bucharest

Optimal dose reduction in computed tomography methodologies predicted from real-time dosimetry

Science.gov (United States)

Tien, Christopher Jason

Over the past two decades, computed tomography (CT) has become an increasingly common and useful medical imaging technique. CT is a noninvasive imaging modality with three-dimensional volumetric viewing abilities, all in sub-millimeter resolution. Recent national scrutiny on radiation dose from medical exams has spearheaded an initiative to reduce dose in CT. This work concentrates on dose reduction of individual exams through two recently-innovated dose reduction techniques: organ dose modulation (ODM) and tube current modulation (TCM). ODM and TCM tailor the phase and amplitude of x-ray current, respectively, used by the CT scanner during the scan. These techniques are unique because they can be used to achieve patient dose reduction without any appreciable loss in image quality. This work details the development of the tools and methods featuring real-time dosimetry which were used to provide pioneering measurements of ODM or TCM in dose reduction for CT.

Status report of the ESR/alanine project of the IAEA Dosimetry Laboratory

International Nuclear Information System (INIS)

Girzikowsky, R.

1990-01-01

The main tasks of the Dosimetry Laboratory of the IAEA are in the field of therapy-level dosimetry. Other dose ranges, i.e. protection-level standardization and calibration, are partly covered, too. On high-dose level the laboratory has been offering a Fricke-dosimetry service to Member States on request since 1965. In 1985 the Dosimetry Section has initiated an International Dose Assurance Service (IDAS). This service is an important part of the Agency's high-dose standardization programme and is based on Electron-Spin-Resonance (ESR) analysis of radiation-induced free radicals in alanine. This ESR/alanine dosimetry system was initially developed for high-dose application by GSF/Munich as the Agency's outside contractor. Although efforts were undertaken to equip the Agency Laboratory with an ESR analyzer since 1984, the purchase of an adequate unit was postponed until the end of 1988. From the date of establishment of the IDAS programme until today, the handling of all technical aspects, i.e. dosimeter production and evaluation was and is carried out by GSP/Munich under IAEA contract. As mentioned above, the IAEA Dosimetry Laboratory is in possession of its own ESR analyzer since December 1988. It was then installed in May 1989. Only one staff member of the laboratory was assigned to this project. He made himself acquainted with the analyzer, the measuring technique, and the application of alanine as dosimeter material. The ESR spectrometric analyzer is a CW ESR type ESP 300 manufactured by Bruker GmbH/FRG. It consists of a 9''/2,7 kW magnet, an X-band microwave bridge, a field regulator unit, a signal channel unit and a data system ESP 1620 based on the 68020 CPU. The probe material selected for measurement of concentration of radiation-induced free radicals is L-Alanine. This amino acid is a suitable material for transfer dosimeters due to its properties, i.e. wide sensitivity range (10 Gy to 100 kGy), energy independence for high-energy photons and electron

Dosimetry Service

CERN Multimedia

2005-01-01

Please remember to read your dosimeter at least once a month. Regular read-outs are vital to ensure that your personal dose is periodically monitored. Dosimeters should be read even if you have not visited the controlled areas. Dosimetry Service - Tel. 72155 http://cern.ch/rp-dosimetry

Radiation dosimetry in nuclear medicine

International Nuclear Information System (INIS)

Stabin, M.G.; Tagesson, M.; Ljungberg, M.; Strand, S.E.; Thomas, S.R.

1999-01-01

Radionuclides are used in nuclear medicine in a variety of diagnostic and therapeutic procedures. A knowledge of the radiation dose received by different organs in the body is essential to an evaluation of the risks and benefits of any procedure. In this paper, current methods for internal dosimetry are reviewed, as they are applied in nuclear medicine. Particularly, the Medical Internal Radiation Dose (MIRD) system for dosimetry is explained, and many of its published resources discussed. Available models representing individuals of different age and gender, including those representing the pregnant woman are described; current trends in establishing models for individual patients are also evaluated. The proper design of kinetic studies for establishing radiation doses for radiopharmaceuticals is discussed. An overview of how to use information obtained in a dosimetry study, including that of the effective dose equivalent (ICRP 30) and effective dose (ICRP 60), is given. Current trends and issues in internal dosimetry, including the calculation of patient-specific doses and in the use of small scale and microdosimetry techniques, are also reviewed

Clinical dosimetry

International Nuclear Information System (INIS)

Rassow, J.

1973-01-01

The main point of this paper on clinical dosimetry which is to be understood here as application of physical dosimetry on accelerators in medical practice, is based on dosimetric methodics. Following an explanation of the dose parameters and description of the dose distribution important for clinical practice as well as geometric irradiation parameters, the significance of a series of physical parameters such as accelerator energy, surface energy of average stopping power etc. is dealt with in detail. Following a section on field homogenization with bremsstrahlung and electron radiation, details on dosimetry in clinical practice are given. Finally, a few problems of dosemeter or monitor calibration on accelerators are described. The explanations are supplemented by a series of diagrams and tables. (ORU/LH) [de

Textbook of dosimetry. 4. ed.

International Nuclear Information System (INIS)

Ivanov, V.I.

1999-01-01

This textbook of dosimetry is devoted to the students in physics and technical physics of high education institutions, confronted with different application of atomic energy as well as with protection of population and environment against ionizing radiations. Atomic energy is highly beneficial for man but unfortunately incorporates potential dangers which manifest in accidents, the source of which is either insufficient training of the personnel, a criminal negligence or insufficient reliability of the nuclear facilities. The majority of the incident and accident events have had as origin the personnel errors. This was the case with both the 'Three Miles Island' (1979) and Chernobyl (1986) NPP accidents. The dosimetry science acquires a vital significance in accident situations since the data obtained by its procedures are essential in choosing the correct immediate actions, behaviour tactics, orientation of liquidation of accident consequences as well as in ensuring the health of population. An important accent is placed in this manual on clarification of the nature of physical processes taken place in dosimetric detectors, in establishing the relation between radiation field characteristics and the detector response as well as in defining different dosimetric quantities. The terminology and the units of physical quantities is based on the international system of units. The book contains the following 15 chapters: 1. Ionizing radiation field; 2. Radiation doses; 3. Physical bases of gamma radiation dosimetry; 4. Ionization dosimetric detectors; 5. Semiconductor dosimetric detectors; 6. Scintillation detection in the gamma radiation dosimetry; 7. Luminescent methods in dosimetry; 8. The photographic and chemical methods of gamma radiation dosimetry; 9. Neutron dosimetry; 10. Dosimetry of high intensity radiation; 11. Dosimetry of high energy Bremsstrahlung; 12. Measurement of the linear energy transfer; 13. Microdosimetry; 14. Dosimetry of incorporated

Using thermoluminescence dosimetry (TLD) to determine the gonadal dose of patients under-going chest X-ray examinations at NKST hospital, Mkar

International Nuclear Information System (INIS)

Agba, E.H.; Akaagerger, N.B.; Kungur, S.T.

2011-01-01

The doses absorbed by the gonads of patients undergoing chest X-ray examinations at NKST Christian Hospital, Mkar was determined using the Thermoluminescence Dosimetry Technique of measurement. Also, the direct X-ray dose to the chest of patients undergoing the routine examinations was also determined using the Thermolumnescence Dosimetry technique of measurement. The mean gonadal dose and the X-ray dose to the patients were found to be 0.03±0.02μSv and 0.04±0.03mSv respectively after exposure. These X-ray doses to the patients is seen to be within the acceptable recommended X -ray dose limits of 1mGy recommended by ICRP.

In vivo dosimetry in radiation therapy in Sweden

International Nuclear Information System (INIS)

Eriksson, Jacob; Blomquist, Michael

2010-07-01

A prerequisite for achieving high radiation safety for patients receiving external beam radiation therapy is that the hospitals have a quality assurance program. The program should include include monitoring of the radiation dose given to the patient. Control measurements are performed both at the system level and at the individual level. Control measurement is normally performed using in vivo dosimetry, e.g. a method to measure the radiation dose at the individual level during the actual radiation treatment time. In vivo dosimetry has proven to be an important tool to detect and prevent serious errors in patient treatment. The purpose of this research project was to identify the extent to which vivo dosimetry is used and the methods available for this at Swedish radiation therapy clinics. The authority also wanted to get an overall picture of how hospitals manage results of in vivo dosimetry, and how clinics control radiation dose when using modern treatment techniques. The report reflects the situation in Swedish radiotherapy clinics 2007. The report shows that all hospitals use some form of in vivo dosimetry. The instruments used are mainly diodes and termoluminiscence dosimeters

Reduced dose uncertainty in MRI-based polymer gel dosimetry using parallel RF transmission with multiple RF sources

International Nuclear Information System (INIS)

Sang-Young Kim; Jung-Hoon Lee; Jin-Young Jung; Do-Wan Lee; Seu-Ran Lee; Bo-Young Choe; Hyeon-Man Baek; Korea University of Science and Technology, Daejeon; Dae-Hyun Kim; Jung-Whan Min; Ji-Yeon Park

2014-01-01

In this work, we present the feasibility of using a parallel RF transmit with multiple RF sources imaging method (MultiTransmit imaging) in polymer gel dosimetry. Image quality and B 1 field homogeneity was statistically better in the MultiTransmit imaging method than in conventional single source RF transmission imaging method. In particular, the standard uncertainty of R 2 was lower on the MultiTransmit images than on the conventional images. Furthermore, the MultiTransmit measurement showed improved dose resolution. Improved image quality and B 1 homogeneity results in reduced dose uncertainty, thereby suggesting the feasibility of MultiTransmit MR imaging in gel dosimetry. (author)

Dosimetry Service

CERN Multimedia

2005-01-01

Please remember to read your dosimeter at least once a month. Regular read-outs are vital to ensure that your personal dose is periodically monitored. Dosimeters should be read even if you have not visited the controlled areas. Dosimetry Service - Tel. 7 2155 http://cern.ch/rp-dosimetry

Dosimetry Service

CERN Multimedia

Dosimetry Service

2005-01-01

Please remember to read your dosimeter at least once a month. Regular read-outs are vital to ensure that your personal dose is periodically monitored. Dosimeters should be read even if you have not visited the controlled areas. Dosimetry Service Tel. 7 2155 http://cern.ch/rp-dosimetry

Radiographic film dosimetry of proton beams for depth‐dose constancy check and beam profile measurement

Science.gov (United States)

Teran, Anthony; Ghebremedhin, Abiel; Johnson, Matt; Patyal, Baldev

2015-01-01

Radiographic film dosimetry suffers from its energy dependence in proton dosimetry. This study sought to develop a method of measuring proton beams by the film and to evaluate film response to proton beams for the constancy check of depth dose (DD). It also evaluated the film for profile measurements. To achieve this goal, from DDs measured by film and ion chamber (IC), calibration factors (ratios of dose measured by IC to film responses) as a function of depth in a phantom were obtained. These factors imply variable slopes (with proton energy and depth) of linear characteristic curves that relate film response to dose. We derived a calibration method that enables utilization of the factors for acquisition of dose from film density measured at later dates by adapting to a potentially altered processor condition. To test this model, the characteristic curve was obtained by using EDR2 film and in‐phantom film dosimetry in parallel with a 149.65 MeV proton beam, using the method. An additional validation of the model was performed by concurrent film and IC measurement perpendicular to the beam at various depths. Beam profile measurements by the film were also evaluated at the center of beam modulation. In order to interpret and ascertain the film dosimetry, Monte Carlos simulation of the beam was performed, calculating the proton fluence spectrum along depths and off‐axis distances. By multiplying respective stopping powers to the spectrum, doses to film and water were calculated. The ratio of film dose to water dose was evaluated. Results are as follows. The characteristic curve proved the assumed linearity. The measured DD approached that of IC, but near the end of the spread‐out Bragg peak (SOBP), a spurious peak was observed due to the mismatch of distal edge between the calibration and measurement films. The width of SOBP and the proximal edge were both reproducible within a maximum of 5 mm; the distal edge was reproducible within 1 mm. At 5 cm depth, the

On the radiation dosimetry in space

International Nuclear Information System (INIS)

Doke, Tadayoshi

2005-01-01

The radiation dosimetry in space is considerably different from that on the earth surface, because, on the earth surface, the quality factor for radiation is roughly given for its energy but, in space, it is defined as a continuous function of LET. Thus, the contribution to the dose equivalent from heavy charged particles included in galactic cosmic rays is more than 50%, because of their high LET values. To evaluate such dose equivalent within an uncertainty of 30%, we must determine the true LET distribution. This paper describes the essence of such a new radiation dosimetry in space. (author)

Calculation of electron and isotopes dose point kernels with FLUKA Monte Carlo code for dosimetry in nuclear medicine therapy

CERN Document Server

Mairani, A; Valente, M; Battistoni, G; Botta, F; Pedroli, G; Ferrari, A; Cremonesi, M; Di Dia, A; Ferrari, M; Fasso, A

2011-01-01

Purpose: The calculation of patient-specific dose distribution can be achieved by Monte Carlo simulations or by analytical methods. In this study, FLUKA Monte Carlo code has been considered for use in nuclear medicine dosimetry. Up to now, FLUKA has mainly been dedicated to other fields, namely high energy physics, radiation protection, and hadrontherapy. When first employing a Monte Carlo code for nuclear medicine dosimetry, its results concerning electron transport at energies typical of nuclear medicine applications need to be verified. This is commonly achieved by means of calculation of a representative parameter and comparison with reference data. Dose point kernel (DPK), quantifying the energy deposition all around a point isotropic source, is often the one. Methods: FLUKA DPKS have been calculated in both water and compact bone for monoenergetic electrons (10-3 MeV) and for beta emitting isotopes commonly used for therapy ((89)Sr, (90)Y, (131)I, (153)Sm, (177)Lu, (186)Re, and (188)Re). Point isotropic...

Establishment of a dosimetric system for high doses using glasses

International Nuclear Information System (INIS)

Correa Quezada, Valeria de la Asuncion

1997-01-01

A routine dosimetric system was developed using commercial glass samples. The dosimetric characteristics of national and imported samples were studied: batch uniformity, response repeatability, reutilization, absorbed dose response, detection range, response stability as a function of absorbed dose, storage temperature and thermal treatments pre- and post-irradiation, using the optical absorption technique. As an application, the dosimetric system was tested in a flower irradiation process at IPEN. All the obtained results show the usefulness of the proposed system for high dose dosimetry. (author)

Personal dosimetry and information platforms

International Nuclear Information System (INIS)

Sanchez Hidalgo, M.; Galan Montenegro, P.; Bodineau Gil, C.; Hernandez Rodriguez, R.; Jimenez Nartin, A.; Cano Sanchez, J. J.

2011-01-01

One question often raised by the hospital personnel dosimetry is the high incidence in the no monthly turnover of dosimeters, which is currently a high number of administrative dose assignments. The high number of workers with personal dosimetry and in many cases, the dispersion of workplaces makes it impossible to personalized management. To make a more direct and personal, and transmit information quickly and with guaranteed reception, has developed and implemented a system of personalized dosimetric information through messaging Short Message Service (SMS) and access to the history of dosimetric dosimetric and management through web space Service Hospital Radio physics.

Applichation of the sulphate ceric dosimetric in the high doses range

International Nuclear Information System (INIS)

Prieto Miranda, F.

1991-01-01

The ceric-cerous dosimetric system is one of the system more employed in the high dose dosimetry. The spectrophotometric procedure to measure the ceric-concentration is an usual analityc method to determine the absorbed dose. On the other hand, due at increase employ of the irradiation process control. In this paper is realized the ceric-cerous dosimetric calibration in the dose range of 0,6 - 5 kGy and the application in the irradiation process control to differents absorbed dose values

Biophysical dosimetry using electron paramagnetic resonance in human tooth

International Nuclear Information System (INIS)

Khan, R.F.H.; Boreham, D.R.; Rink, W.J.

2002-01-01

Accidental dosimetry utilizing radiation induced paramagnetic species in biophysical tissues like teeth is a technique; that can measure the amount of radiation exposure to an individual. The major problem in implementing this technique at low doses is the presence of native organic signal, and various other artifacts produced as a result of sample processing. After a series of experimental trials, we developed an optimum set of rules, which uses high temperature ultrasonic treatment of enamel in KOH, multiple sample rotation during in-cavity measurement of natural and calibrated added irradiations, and dose construction using a backward extrapolation method. By using this we report the successful dose reconstruction in a few of our laboratory samples in 100 mGy range (76.29 ± 30.14) mGy with reasonably low uncertainty. Keywords: biophysical dosimetry, human tooth enamel, low dose measurements, accidental dosimetry (author)

Comparison of radiation doses obtained for radiation monitoring of controlled areas with radiation doses obtained for personnel dosimetry in radiodiagnosis centers

International Nuclear Information System (INIS)

Lescano, Roberto; Caspani, Carlos; Universidad Nacional del Litoral, Santa Fe

2001-01-01

In this paper we propose to search an indicator that shows, at an objective way, the quality of the radioprotection actions. The method is about to determine doses, measured in the work area, connecting them with the workload, and finally get the dose for the center. Them we make a comparison with the personal film dosimetry data. We discuss the final results, evaluating the radioprotection conditions in daily work. (author)

Risks of circulatory diseases among Mayak PA workers with radiation doses estimated using the improved Mayak Worker Dosimetry System 2008

Energy Technology Data Exchange (ETDEWEB)

Moseeva, Maria B.; Azizova, Tamara V.; Grigoryeva, Evgenia S. [Southern Urals Biophysics Institute (SUBI), Ozyorsk, Chelyabinsk Region (Russian Federation); Haylock, Richard [Public Health of England, London (United Kingdom)

2014-05-15

The new Mayak Worker Dosimetry System 2008 (MWDS-2008) was published in 2013 and supersedes the Doses-2005 dosimetry system for Mayak Production Association (PA) workers. It provides revised external and internal dose estimates based on the updated occupational history data. Using MWDS-2008, a cohort of 18,856 workers first employed at one of the main Mayak PA plants during 1948-1972 and followed up to 2005 was identified. Incidence and mortality risks from ischemic heart disease (IHD) (International Classification of Diseases (ICD)-9 codes 410-414) and from cerebrovascular diseases (CVD) (ICD-9 codes 430-438) were examined in this cohort and compared with previously published risk estimates in the same cohort based on the Doses-2005 dosimetry system. Significant associations were observed between doses from external gamma-rays and IHD and CVD incidence and also between internal doses from alpha-radiation and IHD mortality and CVD incidence. The estimates of excess relative risk (ERR)/Gy were consistent with those estimates from the previous studies based on Doses-2005 system apart from the relationship between CVD incidence and internal liver dose where the ERR/Gy based on MWDS-2008 was just over three times higher than the corresponding estimate based on Doses-2005 system. Adjustment for smoking status did not show any effect on the estimates of risk from internal alpha-particle exposure. (orig.)

Radiotherapy gel dosimetry

International Nuclear Information System (INIS)

Baldock, C.

2002-01-01

shapes and sizes while sparing normal tissue. The situation is further complicated if the normal tissues are critical organs or are particularly sensitive to radiation. Radiotherapy techniques employed to obtain a closer conformation of the dose distribution to the tumour volume are referred to as conformal radiotherapy techniques. The clinical implementation of conformal therapy has been delayed by limitations in the verification of conformal dose distributions calculated by treatment planning systems prior to the irradiation of the patient and the verification of complex treatments during its delivery to the patient. There are several aspects of conformal therapy that complicate dose verification. To achieve the dose distributions conforming to complex 3D volumes, high dose gradients arise in the treatment volume. Further, overdose or underdose regions can exist when separate radiation fields are used to deliver additional radiation. These aspects require that practical dose measurement (dosimetry) techniques be able to integrate dose over time and easily measure dose distributions in 3D with high spatial resolution. Traditional dosimeters, such as ion chambers, thermoluminescent dosimeters and radiographic film do not fulfil these requirements. Novel gel dosimetry techniques are being developed in which dose distributions can potentially be determined in vitro in 3D using anthropomorphic phantoms to simulate a clinically irradiated situation. As long ago as the 1950's, radiation-induced colour change in dyes was used to investigate radiation doses in gels. It was subsequently shown that radiation induced changes in nuclear magnetic resonance (NMR) relaxation properties of gels infused with conventional Fricke dosimetry solutions could be measured using magnetic resonance imaging (MRI). In Fricke gels, Fe 2+ ions in ferrous sulphate solutions are usually dispersed throughout a gelatin, agarose or PVA matrix. Radiation-induced changes in the dosimeters are considered to

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

International Nuclear Information System (INIS)

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

2009-01-01

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

Characterization of silicates and calcium carbonates applied to high-dose dosimetry; Caracterizacao de silicatos e carbonatos de calcio aplicados a dosimetria de doses altas

Energy Technology Data Exchange (ETDEWEB)

Vila, Gustavo Barreto

2012-07-01

The predominant isomorphous form in the biominerals studied in this work (oyster shell, coral, mother of pearl and shell) was aragonite. The appearance of the calcite phase occurred at 500 deg C at a heating rate of 10 deg {sup C}/s for all samples except for the coral sample, which was 400 deg C, independent of the heating rate. The most abundant element in the biominerals samples was Ca in the CaO form, and in the silicates (tremolite, diopside and rhodonite) Si in the SiO form. The most common trace element observed in the biominerals samples was Fe. The analyses of electron paramagnetic resonance showed lines of Mn{sup 2+} in the coral and mother-of-pearl samples before irradiation. In the case of the irradiated samples, the defects found were CO{sub 2}{sup -}, CO{sub 3}{sup 3-}, CO{sub 3}{sup -} and SO{sub 2}{sup -}, in the g range between 2.0010 and 2.0062. In the analyses by optical absorption of biominerals, transitions due to the presence of Mn in the samples were found. A thermoluminescent (TL) peak at approximately 140 deg C was found for the biominerals and at 180 deg C for silicates, which intensity depends directly on the dose. For samples exposed to different types of radiation, the TL peak occurred at lower temperatures. From the dose-response curves obtained for these materials, it was possible to determine a linear range for which their application in high dose dosimetry becomes possible. Taking into account the radiation type, among biominerals and silicates, the lowest detectable dose (40mGy) to gamma radiation was achieved for oyster shell samples using the measuring technique of optically stimulated luminescence (OSL). Using beta radiation, for diopside and tremolite samples the lowest detectable dose of 60mGy was obtained. For all samples, using the TL, OSL and thermally stimulated exoelectron emission (TSEE) techniques in alpha, beta and gamma radiation beans a good response reproducibility was obtained. Therefore, the samples characterized

11. International conference on solid radiation dosimetry

International Nuclear Information System (INIS)

Krylova, I.V.

1996-01-01

The main problems discussed during the international conference on solid radiation dosimetry which took place in June 1995 in Budapest are briefly considered. These are the basic physical processes, materials applied for dosimetry, special techniques, personnel monitoring, monitoring of environmental effects, large-dose dosimetry, clinic dosimetry, track detector used for dosimetry, dosimetry in archaeology and geology, equipment and technique for dosimetric measurements. The special attention was paid to superlinearity in the TLD-100 (LiF, Mg, Ti) response function when determining doses of gamma radiation, heavy charged particles, low-energy particle fluxes in particular. New theoretical models were considered

Dosimetry in nuclear power plants

International Nuclear Information System (INIS)

Lastra B, J. A.

2008-12-01

To control the occupationally exposed personnel dose working at the Laguna Verde nuclear power plant, two types of dosemeters are used, the thermoluminescent (TLD) which is processed monthly, and the direct reading dosemeter that is electronic and works as daily control of personal dose. In the case of the electronic dosemeters of direct reading conventional, the readings and dose automatic registers and the user identity to which he was assigned to each dosemeter was to carry out the restricted area exit. In activities where the ionizing radiation sources are not fully characterized, it is necessary to relocate the personal dosemeter or assigned auxiliary dosemeters (TLDs and electronics) to determine the dose received by the user to both whole body and in any specific area of it. In jobs more complicated are used a tele dosimetry system where the radiation protection technician can be monitoring the user dose to remote control, the data transmission is by radio. The dosimetry activities are documented in procedures that include dosemeter inventories realization, the equipment and dosemeters calibration, the dosimetry quality control and the discrepancies investigation between the direct reading and TLD systems. TLD dosimetry to have technical expertise in direct and indirect dosimetry and two technicians in TLD dosimetry; electronic dosimetry to have 4 calibration technicians. For the electronic dosemeters are based on a calibrator source of Cesium-137. TLD dosemeters to have an automatic radiator, an automatic reader which can read up to 100 TLD dosemeters per hour and a semiautomatic reader. To keep the equipment under a quality process was development a process of initial entry into service and carried out a periodic verification of the heating cycles. It also has a maintenance contract for the equipment directly with the manufacturer to ensure their proper functioning. The vision in perspective of the dosimetry services of Laguna Verde nuclear power plant

Contralateral breast doses measured by film dosimetry: tangential techniques and an optimized IMRT technique

International Nuclear Information System (INIS)

Saur, S; Frengen, J; Fjellsboe, L M B; Lindmo, T

2009-01-01

The contralateral breast (CLB) doses for three tangential techniques were characterized by using a female thorax phantom and GafChromic EBT film. Dose calculations by the pencil beam and collapsed cone algorithms were included for comparison. The film dosimetry reveals a highly inhomogeneous dose distribution within the CLB, and skin doses due to the medial fields that are several times higher than the interior dose. These phenomena are not correctly reproduced by the calculation algorithms. All tangential techniques were found to give a mean CLB dose of approximately 0.5 Gy. All wedged fields resulted in higher CLB doses than the corresponding open fields, and the lateral open fields resulted in higher CLB doses than the medial open fields. More than a twofold increase in the mean CLB dose from the medial open field was observed for a 90 deg. change of the collimator orientation. Replacing the physical wedge with a virtual wedge reduced the mean dose to the CLB by 35% and 16% for the medial and lateral fields, respectively. Lead shielding reduced the skin dose for a tangential technique by approximately 50%, but the mean CLB dose was only reduced by approximately 11%. Finally, a technique based on open medial fields in combination with several IMRT fields is proposed as a technique for minimizing the CLB dose. With and without lead shielding, the mean CLB dose using this technique was found to be 0.20 and 0.27 Gy, respectively.

Use of glasses as radiation detectors for high doses

International Nuclear Information System (INIS)

Caldas, L.

1989-08-01

Glass samples were tested in relation to the possibility of use in high dose dosimetry in medical and industrial areas. The main characteristics were determined: detection threshold, reproducibility, response to gamma radiation of 137 Cs and 6 Co and thermal decay at ambient temperature, with the use of optical absorption and thermoluminesce techniques. (author) [pt

Dosimetry for radiation processing

International Nuclear Information System (INIS)

McLaughlin, W.L.; Boyd, A.W.; Chadwick, K.H.; McDonald, J.C.; Miller, A.

1989-01-01

Radiation processing is a relatively young industry with broad applications and considerable commercial success. Dosimetry provides an independent and effective way of developing and controlling many industrial processes. In the sterilization of medical devices and in food irradiation, where the radiation treatment impacts directly on public health, the measurements of dose provide the official means of regulating and approving its use. In this respect, dosimetry provides the operator with a means of characterizing the facility, of proving that products are treated within acceptable dose limits and of controlling the routine operation. This book presents an up-to-date review of the theory, data and measurement techniques for radiation processing dosimetry in a practical and useful way. It is hoped that this book will lead to improved measurement procedures, more accurate and precise dosimetry and a greater appreciation of the necessity of dosimetry for radiation processing. (author)

Absolute and relative dose measurements with Gafchromic trade mark sign EBT film for high energy electron beams with different doses per pulse

International Nuclear Information System (INIS)

Fiandra, Christian; Ragona, Riccardo; Ricardi, Umberto; Anglesio, Silvia; Giglioli, Francesca Romana

2008-01-01

The authors have evaluated the accuracy, in absolute and relative dose measurements, of the Gafchromic trade mark sign EBT film in pulsed high-energy electron beams. Typically, the electron beams used in radiotherapy have a dose-per-pulse value of less than 0.1 mGy/pulse. However, very high dose-per-pulse electron beams are employed in certain linear accelerators dedicated to intraoperatory radiation therapy (IORT). In this study, the absorbed dose measurements with Gafchromic trade mark sign EBT in both low (less than 0.3 mGy per pulse) and high (30 and 70 mGy per pulse) dose-per-pulse electron beams were compared with ferrous sulfate chemical Fricke dosimetry (operated by the Italian Primary Standard Dosimetry Laboratory), a method independent of the dose per pulse. A summary of Gafchromic trade mark sign EBT in relative and absolute beam output determination is reported. This study demonstrates the independence of Gafchromic trade mark sign EBT absorption as a function of dose per pulse at different dose levels. A good agreement (within 3%) was found with Fricke dosimeters for plane-base IORT applicators. Comparison with a diode detector is presented for relative dose measurements, showing acceptable agreement both in the steep dose falloff zone and in the homogeneous dose region. This work also provides experimental values for recombination correction factor (K sat ) of a Roos (plane parallel) ionization chamber calculated on the basis of theoretical models for charge recombination.

Reconstructive dosimetry for cutaneous radiation syndrome

Energy Technology Data Exchange (ETDEWEB)

Lima, C.M.A.; Lima, A.R.; Degenhardt, Ä.L.; Da Silva, F.C.A., E-mail: dasilva@ird.gov.br [Instituto de Radioprotecao e Dosimetria (IRD/CNEN-RJ), Rio de Janeiro, RJ (Brazil); Valverde, N.J. [Fundacao Eletronuclear de Assistencia Medica, Rio de Janeiro, RJ (Brazil)

2015-10-15

According to the International Atomic Energy Agency (IAEA), a relatively significant number of radiological accidents have occurred in recent years mainly because of the practices referred to as potentially high-risk activities, such as radiotherapy, large irradiators and industrial radiography, especially in gammagraphy assays. In some instances, severe injuries have occurred in exposed persons due to high radiation doses. In industrial radiography, 80 cases involving a total of 120 radiation workers, 110 members of the public including 12 deaths have been recorded up to 2014. Radiological accidents in industrial practices in Brazil have mainly resulted in development of cutaneous radiation syndrome (CRS) in hands and fingers. Brazilian data include 5 serious cases related to industrial gammagraphy, affecting 7 radiation workers and 19 members of the public; however, none of them were fatal. Some methods of reconstructive dosimetry have been used to estimate the radiation dose to assist in prescribing medical treatment. The type and development of cutaneous manifestations in the exposed areas of a person is the first achievable gross dose estimation. This review article presents the state-of-the-art reconstructive dosimetry methods enabling estimation of local radiation doses and provides guidelines for medical handling of the exposed individuals. The review also presents the Chilean and Brazilian radiological accident cases to highlight the importance of reconstructive dosimetry. (author)

Individual Dosimetry for High Energy Radiation Fields

International Nuclear Information System (INIS)

Spurny, F.

1999-01-01

The exposure of individuals on board aircraft increased interest in individual dosimetry in high energy radiation fields. These fields, both in the case of cosmic rays as primary radiation and at high energy particle accelerators are complex, with a large diversity of particle types, their energies, and linear energy transfer (LET). Several already existing individual dosemeters have been tested in such fields. For the component with high LET (mostly neutrons) etched track detectors were tested with and without fissile radiators, nuclear emulsions, bubble detectors for both types available and an albedo dosemeter. Individual dosimetry for the low LET component has been performed with thermoluminescent detectors (TLDs), photographic film dosemeters and two types of electronic individual dosemeters. It was found that individual dosimetry for the low LET component was satisfactory with the dosemeters tested. As far as the high LET component is concerned, there are problems with both the sensitivity and the energy response. (author)

Heterogeneity phantoms for visualization of 3D dose distributions by MRI-based polymer gel dosimetry

International Nuclear Information System (INIS)

Watanabe, Yoichi; Mooij, Rob; Mark Perera, G.; Maryanski, Marek J.

2004-01-01

Heterogeneity corrections in dose calculations are necessary for radiation therapy treatment plans. Dosimetric measurements of the heterogeneity effects are hampered if the detectors are large and their radiological characteristics are not equivalent to water. Gel dosimetry can solve these problems. Furthermore, it provides three-dimensional (3D) dose distributions. We used a cylindrical phantom filled with BANG-3 registered polymer gel to measure 3D dose distributions in heterogeneous media. The phantom has a cavity, in which water-equivalent or bone-like solid blocks can be inserted. The irradiated phantom was scanned with an magnetic resonance imaging (MRI) scanner. Dose distributions were obtained by calibrating the polymer gel for a relationship between the absorbed dose and the spin-spin relaxation rate of the magnetic resistance (MR) signal. To study dose distributions we had to analyze MR imaging artifacts. This was done in three ways: comparison of a measured dose distribution in a simulated homogeneous phantom with a reference dose distribution, comparison of a sagittally scanned image with a sagittal image reconstructed from axially scanned data, and coregistration of MR and computed-tomography images. We found that the MRI artifacts cause a geometrical distortion of less than 2 mm and less than 10% change in the dose around solid inserts. With these limitations in mind we could make some qualitative measurements. Particularly we observed clear differences between the measured dose distributions around an air-gap and around bone-like material for a 6 MV photon beam. In conclusion, the gel dosimetry has the potential to qualitatively characterize the dose distributions near heterogeneities in 3D

Rectal dose assessment in patients submitted to high-dose-rate brachytherapy for uterine cervix cancer

International Nuclear Information System (INIS)

Oliveira, Jetro Pereira de; Batista, Delano Valdivino Santos; Bardella, Lucia Helena; Carvalho, Arnaldo Rangel

2009-01-01

Objective: The present study was aimed at developing a thermoluminescent dosimetric system capable of assessing the doses delivered to the rectum of patients submitted to high-dose-rate brachytherapy for uterine cervix cancer. Materials and methods: LiF:Mg,Ti,Na powder was the thermoluminescent material utilized for evaluating the rectal dose. The powder was divided into small portions (34 mg) which were accommodated in a capillary tube. This tube was placed into a rectal probe that was introduced into the patient's rectum. Results: The doses delivered to the rectum of six patients submitted to high-dose-rate brachytherapy for uterine cervix cancer evaluated by means of thermoluminescent dosimeters presented a good agreement with the planned values based on two orthogonal (anteroposterior and lateral) radiographic images of the patients. Conclusion: The thermoluminescent dosimetric system developed in the present study is simple and easy to be utilized as compared to other rectal dosimetry methods. The system has shown to be effective in the evaluation of rectal doses in patients submitted to high-dose-rate brachytherapy for uterine cervix cancer. (author)

Extra-high doses detected in the enamel of human teeth in the Techa riverside region

Energy Technology Data Exchange (ETDEWEB)

Shishkina, E.A., E-mail: ElenaA.Shishkina@gmail.com [Urals Research Center for Radiation Medicine, 68A, Vorovsky Str., 454076 Chelyabinsk (Russian Federation); Degteva, M.O.; Tolstykh, E.I.; Volchkova, A. [Urals Research Center for Radiation Medicine, 68A, Vorovsky Str., 454076 Chelyabinsk (Russian Federation); Ivanov, D.V. [Institute of Metal Physics, Russian Academy of Sciences, 18 S. Kovalevsky Str, 620041 Yekaterinburg (Russian Federation); Wieser, A. [Helmholtz Zentrum Muenchen, German Research Centre for Environmental Health, D-85764 Neuherberg (Germany); Della Monaca, S. [Istituto Superiore di Sanita, 00161 Rome (Italy); Istituto Regina Elena, 00144 Rome (Italy); Fattibene, P. [Istituto Superiore di Sanita, 00161 Rome (Italy); Istituto Nazionale di Fisica Nucleare, 00161 Rome (Italy)

2011-09-15

During the long-term study of tooth enamel by EPR dosimetry for population exposed to radiation due to contamination of the Techa River, it was found out that for some of the tooth donors the dose accumulated in tooth enamel could be as high as several tens of Gy. Such doses were absorbed only in tooth enamel and they should not be associated with exposures to other organs or the whole body. The nature of such doses was discussed in a number of previous papers where it was shown that the source of such doses is {sup 90}Sr incorporated in the calcified dental tissues. However, among specialists in radiation dosimetry who were not involved in the biokinetic studies, the nature and dosimetric significance of extra-high doses in tooth enamel are still raising questions. The aim of the current paper is to summarize the accumulated information on extra-high doses in the teeth of the Techa riverside residents, describe the dose levels observed, explain the nature of extra-high doses in the enamel and discuss their informative value. The paper includes an overview of already published findings and an analysis of information collected in the data bank of the Urals Research Center for Radiation Medicine (URCRM), Chelyabinsk, Russia, which has not been published before.

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)

ESR Dosimetry

International Nuclear Information System (INIS)

Baffa, Oswaldo; Rossi, Bruno; Graeff, Carlos; Kinoshita, Angela; Chen Abrego, Felipe; Santos, Adevailton Bernardo dos

2004-01-01

ESR dosimetry is widely used for several applications such as dose assessment in accidents, medical applications and sterilization of food and other materials. In this work the dosimetric properties of natural and synthetic Hydroxyapatite, Alanine, and 2-Methylalanine are presented. Recent results on the use of a K-Band (24 GHz) ESR spectrometer in dosimetry are also presented

Dosimetry techniques applied to thermoluminescent age estimation

International Nuclear Information System (INIS)

Erramli, H.

1986-12-01

The reliability and the ease of the field application of the measuring techniques of natural radioactivity dosimetry are studied. The natural radioactivity in minerals in composed of the internal dose deposited by alpha and beta radiations issued from the sample itself and the external dose deposited by gamma and cosmic radiations issued from the surroundings of the sample. Two technics for external dosimetry are examined in details. TL Dosimetry and field gamma dosimetry. Calibration and experimental conditions are presented. A new integrated dosimetric method for internal and external dose measure is proposed: the TL dosimeter is placed in the soil in exactly the same conditions as the sample ones, during a time long enough for the total dose evaluation [fr

High frequency electromagnetic dosimetry

CERN Document Server

Sánchez-Hernández, David A

2009-01-01

Along with the growth of RF and microwave technology applications, there is a mounting concern about the possible adverse effects over human health from electromagnetic radiation. Addressing this issue and putting it into perspective, this groundbreaking resource provides critical details on the latest advances in high frequency electromagnetic dosimetry.

Assessment of the feasibility of using transrectal ultrasound for postimplant dosimetry in low-dose-rate prostate brachytherapy

Energy Technology Data Exchange (ETDEWEB)

Davies, Rhian Siân, E-mail: rhian.s.davies@wales.nhs.uk; Perrett, Teresa; Powell, Jane; Barber, Jim; Tanguay, Jacob; Button, Michael; Cochlin, Dennis; Smith, Christian; Lester, Jason Francis

2016-01-01

A study was performed to establish whether transrectal ultrasound (TRUS)-based postimplant dosimetry (PID) is both practically feasible and comparable to computed tomography (CT)-based PID, recommended in current published guidelines. In total, 22 patients treated consecutively at a single cancer center with low-dose-rate (LDR) brachytherapy for early-stage prostate cancer had a transrectal ultrasound performed immediately after implant (d0-TRUS) and computed tomography scan 30 days after implant (d30-CT). Postimplant dosimetry planning was performed on both image sets and the results were compared. The interobserver reproducibility of the transrectal ultrasound postimplant dosimetry planning technique was also assessed. It was noticed that there was no significant difference in mean prostate D{sub 90} (136.5 Gy and 144.4 Gy, p = 0.2197), V{sub 100} (86.4% and 89.1%, p = 0.1480) and V{sub 150} (52.0% and 47.8%, p = 0.1657) for d30-CT and d0-TRUS, respectively. Rectal doses were significantly higher for d0-TRUS than d30-CT. Urethral doses were available with d0-TRUS only. We have shown that d0-TRUS PID is a useful tool for assessing the quality of an implant after low-dose-rate prostate brachytherapy and is comparable to d30-CT PID. There are clear advantages to its use in terms of resource and time efficiency both for the clinical team and the patient.

A practical and transferable methodology for dose estimation in irradiated spices based on thermoluminescence dosimetry

International Nuclear Information System (INIS)

D'Oca, M.C.; Bartolotta, A.; Cammilleri, C.; Giuffrida, S.; Parlato, A.; Di Stefano, V.

2008-01-01

Full text: Among the industrial applications of ionizing radiation, the treatment of food for preservation purposes is a worldwide recognized tool, provided that proper and validated identification methods are available and used. The thermoluminescence (TL) dosimetry is the physical method validated by the European Committee for Standardization for food from which silicate minerals can be isolated, such as spices and aromatic herbs. The aim of this work was to set up a reasonably simple procedure, alternative to the recommended one, for the identification of irradiated spices and to estimate at the same time the original dose in the irradiated product, using TL and the additive dose method, even after months storage. We have already shown that the additive dose method can be applied with TL dosimetry, if the TL response of the silicate specimen after extraction is always added to the response after each irradiation; the applied added doses were higher than 1 kGy, that can however give saturation problems. The new proposed methodology makes use of added doses lower than 600 Gy; the entire process can be completed within few hours and a linear fit can be utilized. The method was applied to the silicates extracted from oregano samples soon after the radiation treatment (original dose: 2 - 3 - 5 kGy), and after one year storage at room conditions in the dark (original dose: 1-2 kGy). The procedure allows the identification of irradiated samples, without any false positive, together with an estimation of the dose range

Dosimetry system of the RB reactor; Dozimetarski sistem reaktora RB

Energy Technology Data Exchange (ETDEWEB)

Lolic, B; Vukadin, D [Boris Kidric Institute of nuclear sciences, Vinca, Belgrade (Yugoslavia)

1962-07-01

Although RB reactor is operated at very low power levels, safety and dosimetry systems have high importance. This paper shows detailed dosimetry system with fundamental typical components. Estimated radiation doses dependent on reactor power are given at some characteristic points in the rooms nearby reactor.

Personnel Dosimetry for Radiation Accidents. Proceedings of a Symposium on Personnel Dosimetry for Accidental High-Level Exposure to External and Internal Radiation

International Nuclear Information System (INIS)

1965-01-01

Accidents involving the exposure of persons to high levels of radiation have been few in number and meticulous precautions are taken in an effort to maintain this good record. When, however, such an accident does occur, a timely estimate of the dose received can be of considerable help to the physician in deciding whether a particular person requires medical treatment, and in selecting the most appropriate treatment. Individual dosimetry provides the physical basis for relating the observed effects to those in other accident cases, to other human data, and to data from animal experiments, thus providing an important aid to rational treatment and to the accumulation of a meaningful body of knowledge on the subject. It is most important therefore that, where there is a possibility of receiving high-level exposure, methods of personnel dosimetry should be available that would provide the dosimetric information most useful to the physician. Provision of good personnel dosimetry for accidental high-level exposure is in many cases an essential part of emergency planning because the information provided may influence emergency and rescue operations, and can lead to improved accident preparedness. Accordingly, the International Atomic Energy Agency and the World Health Organization jointly organized the Symposium on Personnel Dosimetry for Accidental High-Level Exposure to External and Internal Radiation for the discussion of such methods and for a critical review of the procedures adopted in some of the radiation accidents that have already occurred. The meeting was attended by 179 participants from 34 countries and from five other international organizations. The papers presented and the ensuing discussions are published in these Proceedings. It is hoped that the Proceedings will be of help to those concerned with the organization and development of wide-range personnel monitoring systems, and with the interpretation of the results provided

Thermoluminescent dosimetry of new phosphors of Zn O exposed to beta radiation

International Nuclear Information System (INIS)

Cruz V, C.; Burruel I, S.E.; Grijalva M, H.; Barboza F, M.; Bernal, R.

2004-01-01

In this work, we report the thermoluminescence dosimetry of a new Zn O phosphor obtained by annealing of Zn S powder precipitated when Zn S films were grown by employing a CBD method. The collected Zn S powder was pressed in a die to form pellets which were subjected to different thermal treatments under air atmosphere. X-ray diffraction (XRD) patterns and energy-dispersive X-ray Spectrometry (EDS) analyses confirmed the transformation of Zn S to Zn O. The phosphors thus obtained were exposed to high doses of beta radiation and their thermoluminescent dosimetry show that these new phosphors are materials suitable to be used in high dose thermoluminescence dosimetry. (Author)

Interfractional trend analysis of dose differences based on 2D transit portal dosimetry

International Nuclear Information System (INIS)

Persoon, L C G G; Nijsten, S M J J G; Wilbrink, F J; Podesta, M; Snaith, J A D; Lustberg, T; Van Elmpt, W J C; Van Gils, F; Verhaegen, F

2012-01-01

Dose delivery of a radiotherapy treatment can be influenced by a number of factors. It has been demonstrated that the electronic portal imaging device (EPID) is valuable for transit portal dosimetry verification. Patient related dose differences can emerge at any time during treatment and can be categorized in two types: (1) systematic—appearing repeatedly, (2) random—appearing sporadically during treatment. The aim of this study is to investigate how systematic and random information appears in 2D transit dose distributions measured in the EPID plane over the entire course of a treatment and how this information can be used to examine interfractional trends, building toward a methodology to support adaptive radiotherapy. To create a trend overview of the interfractional changes in transit dose, the predicted portal dose for the different beams is compared to a measured portal dose using a γ evaluation. For each beam of the delivered fraction, information is extracted from the γ images to differentiate systematic from random dose delivery errors. From the systematic differences of a fraction for a projected anatomical structures, several metrics are extracted like percentage pixels with |γ| > 1. We demonstrate for four example cases the trends and dose difference causes which can be detected with this method. Two sample prostate cases show the occurrence of a random and systematic difference and identify the organ that causes the difference. In a lung cancer case a trend is shown of a rapidly diminishing atelectasis (lung fluid) during the course of treatment, which was detected with this trend analysis method. The final example is a breast cancer case where we show the influence of set-up differences on the 2D transit dose. A method is presented based on 2D portal transit dosimetry to record dose changes throughout the course of treatment, and to allow trend analysis of dose discrepancies. We show in example cases that this method can identify the causes of

Cellular dosimetry in nuclear medicine imaging: training

International Nuclear Information System (INIS)

Gardin, I.; Faraggi, M.; Stievenart, J.L.; Le Guludec, D.; Bok, B.

1998-01-01

The radionuclides used in nuclear medicine imaging emit not only diagnostically useful photons, but also energy electron emissions, responsible for dose heterogeneity at the cellular level. The mean dose delivered to the cell nucleus by electron emissions of 99m Tc, 123 I, 111 In, 67 Ga, and 201 Tl, has been calculated, for the cell nucleus, a cytoplasmic and a cell membrane distribution of radioactivity. This model takes into account both the self-dose which results from the radionuclide located in the target cell, and the cross-dose, which comes from the surrounding cells. The results obtained by cellular dosimetry (D cel ) have been compared with those obtained with conventional dosimetry (D conv ), by assuming the same amount of radioactivity per cell. Cellular dosimetry shows, for a cytoplasmic and a cell membrane distributions of radioactivity, that the main contribution to the dose to the cell nucleus, comes from the surrounding cells. On the other hand, for a cell nucleus distribution of radioactivity, the self-dose is not negligible and may be the main contribution. The comparison between cellular and conventional dosimetry shows that D cel /D conv ratio ranges from 0.61 and O.89, in case of a cytoplasmic and a cell membrane distributions of radioactivity, depending on the radionuclide and cell dimensions. Thus, conventional dosimetry slightly overestimates the mean dose to the cell nucleus. On the other hand, D cel /D conv ranges from 1.1 to 75, in case of a cell nucleus distribution of radioactivity. Conventional dosimetry may strongly underestimates the absorbed dose to the nucleus, when radioactivity is located in the nucleus. The study indicates that in nuclear medicine imaging, cellular dosimetry may lead to a better understanding of biological effects of radiopharmaceuticals. (authors)

Dosimetry of beams for negative pi-meson radiation therapy

International Nuclear Information System (INIS)

Dicello, J.F.

1976-01-01

Several new facilities have been built in the last few years which can produce high intensity beams of pions. As a result, a significant amount of new data related to pion dosimetry is available. Results of beam composition, beam shaping, and collimation are given along with depth dose curves and isodose contours. Experimental data which describe the radiation quality of pion beams and the change in radiation quality with position are presented. Experimental data determining the fraction of the dose resulting from neutrons are discussed. The present techniques used in pion dosimetry are summarized, and those areas of pion dosimetry which require additional effort in order to achieve routine treatment planning for patients are reviewed

Tissue equivalence in neutron dosimetry

International Nuclear Information System (INIS)

Nutton, D.H.; Harris, S.J.

1980-01-01

A brief review is presented of the essential features of neutron tissue equivalence for radiotherapy and gives the results of a computation of relative absorbed dose for 14 MeV neutrons, using various tissue models. It is concluded that for the Bragg-Gray equation for ionometric dosimetry it is not sufficient to define the value of W to high accuracy and that it is essential that, for dosimetric measurements to be applicable to real body tissue to an accuracy of better than several per cent, a correction to the total absorbed dose must be made according to the test and tissue atomic composition, although variations in patient anatomy and other radiotherapy parameters will often limit the benefits of such detailed dosimetry. (U.K.)

Use of electron paramagnetic resonance dosimetry with tooth enamel for retrospective dose assessment. Report of a co-ordinated research project

Energy Technology Data Exchange (ETDEWEB)

NONE

2002-12-01

Electron paramagnetic resonance (EPR) dosimetry is a physical method for the assessment of absorbed dose from ionising radiation. It is based on the measurement of stable radiation induced radicals in human calcified tissues (primarily in tooth enamel). EPR dosimetry with teeth is now firmly established in retrospective dosimetry. It is a powerful method for providing information on exposure to ionising radiation many years after the event, since the 'signal' is 'stored' in the tooth or the bone. This technique is of particular relevance to relatively low dose exposures or when the results of conventional dosimetry are not available (e.g. in accidental circumstances). The use of EPR dosimetry, as an essential tool for retrospective assessment of radiation exposure is an important part of radioepidemiological studies and also provides data to select appropriate countermeasures based on retrospective evaluation of individual doses. Despite well established regulations and protocols for maintaining radiation protection dose limits, the assurance that these limits will not be exceeded cannot be guaranteed, thus providing new challenges for development of accurate methods of individual dose assessment. To meet some of these challenges, in 1998 the IAEA initiated a co-ordinated research project (CRP) with the objective to review the available methods, current research and development in EPR biodosimetry technology, which may be of practical use. The major goal of this CRP was to investigate the use of EPR biodosimetry for reconstruction of absorbed dose in tooth enamel with the aim of providing Member States with up-to-date, and generally agreed upon advice regarding the most suitable procedures and the best focus for their research. The co-ordinated research project was conducted over four years and this publication presents the results and findings by a group of investigators from different countries. The available cytogenetic methods for radiation dose assessment were

Use of electron paramagnetic resonance dosimetry with tooth enamel for retrospective dose assessment. Report of a co-ordinated research project

International Nuclear Information System (INIS)

2002-12-01

Electron paramagnetic resonance (EPR) dosimetry is a physical method for the assessment of absorbed dose from ionising radiation. It is based on the measurement of stable radiation induced radicals in human calcified tissues (primarily in tooth enamel). EPR dosimetry with teeth is now firmly established in retrospective dosimetry. It is a powerful method for providing information on exposure to ionising radiation many years after the event, since the 'signal' is 'stored' in the tooth or the bone. This technique is of particular relevance to relatively low dose exposures or when the results of conventional dosimetry are not available (e.g. in accidental circumstances). The use of EPR dosimetry, as an essential tool for retrospective assessment of radiation exposure is an important part of radioepidemiological studies and also provides data to select appropriate countermeasures based on retrospective evaluation of individual doses. Despite well established regulations and protocols for maintaining radiation protection dose limits, the assurance that these limits will not be exceeded cannot be guaranteed, thus providing new challenges for development of accurate methods of individual dose assessment. To meet some of these challenges, in 1998 the IAEA initiated a co-ordinated research project (CRP) with the objective to review the available methods, current research and development in EPR biodosimetry technology, which may be of practical use. The major goal of this CRP was to investigate the use of EPR biodosimetry for reconstruction of absorbed dose in tooth enamel with the aim of providing Member States with up-to-date, and generally agreed upon advice regarding the most suitable procedures and the best focus for their research. The co-ordinated research project was conducted over four years and this publication presents the results and findings by a group of investigators from different countries. The available cytogenetic methods for radiation dose assessment were

Dosimetry characteristics of the Leksell gamma knife for stereotactic radiosurgery

International Nuclear Information System (INIS)

Wu, A.; Lindner, G.; Maitz, A.; Smarra, N.; Turco, R.F.; Kalend, A.M.; Lunsford, L.D.; Flickinger, J.C.; Bloomer, W.D.

1988-01-01

Gamma knife radiosurgery refers to the treatment procedure that delivers very high dose to a small brain lesion with 201 highly focused beams of Co-60. The hemispheric array of these multiple sources with the sizes of beams ranging from 4, 8, 14, to 18 mm makes the determination of dosimetry characteristics of the radiation field very complex. This paper describes the structures, operations, and dose characteristics of gamma knife. Dosimetry measurements were made using ion chamber, TLD, diode, and films to calibrate the dose outputs of the combination of 201 beams of 4, 8, 14, or 18 mm in diameter irradiating from various directions. Results of measured isodose distribution and dose profiles for the various diameter beams are also presented

MO-B-BRB-03: 3D Dosimetry in the Clinic: Validating Special Techniques

Energy Technology Data Exchange (ETDEWEB)

Juang, T. [Stanford Cancer Center (United States)

2016-06-15

Full three-dimensional (3D) dosimetry using volumetric chemical dosimeters probed by 3D imaging systems has long been a promising technique for the radiation therapy clinic, since it provides a unique methodology for dose measurements in the volume irradiated using complex conformal delivery techniques such as IMRT and VMAT. To date true 3D dosimetry is still not widely practiced in the community; it has been confined to centres of specialized expertise especially for quality assurance or commissioning roles where other dosimetry techniques are difficult to implement. The potential for improved clinical applicability has been advanced considerably in the last decade by the development of improved 3D dosimeters (e.g., radiochromic plastics, radiochromic gel dosimeters and normoxic polymer gel systems) and by improved readout protocols using optical computed tomography or magnetic resonance imaging. In this session, established users of some current 3D chemical dosimeters will briefly review the current status of 3D dosimetry, describe several dosimeters and their appropriate imaging for dose readout, present workflow procedures required for good dosimetry, and analyze some limitations for applications in select settings. We will review the application of 3D dosimetry to various clinical situations describing how 3D approaches can complement other dose delivery validation approaches already available in the clinic. The applications presented will be selected to inform attendees of the unique features provided by full 3D techniques. Learning Objectives: L. John Schreiner: Background and Motivation Understand recent developments enabling clinically practical 3D dosimetry, Appreciate 3D dosimetry workflow and dosimetry procedures, and Observe select examples from the clinic. Sofie Ceberg: Application to dynamic radiotherapy Observe full dosimetry under dynamic radiotherapy during respiratory motion, and Understand how the measurement of high resolution dose data in an

MO-B-BRB-01: 3D Dosimetry in the Clinic: Background and Motivation

Energy Technology Data Exchange (ETDEWEB)

Schreiner, L. [Cancer Center of Southeastern Ontario (Canada)

2016-06-15

Full three-dimensional (3D) dosimetry using volumetric chemical dosimeters probed by 3D imaging systems has long been a promising technique for the radiation therapy clinic, since it provides a unique methodology for dose measurements in the volume irradiated using complex conformal delivery techniques such as IMRT and VMAT. To date true 3D dosimetry is still not widely practiced in the community; it has been confined to centres of specialized expertise especially for quality assurance or commissioning roles where other dosimetry techniques are difficult to implement. The potential for improved clinical applicability has been advanced considerably in the last decade by the development of improved 3D dosimeters (e.g., radiochromic plastics, radiochromic gel dosimeters and normoxic polymer gel systems) and by improved readout protocols using optical computed tomography or magnetic resonance imaging. In this session, established users of some current 3D chemical dosimeters will briefly review the current status of 3D dosimetry, describe several dosimeters and their appropriate imaging for dose readout, present workflow procedures required for good dosimetry, and analyze some limitations for applications in select settings. We will review the application of 3D dosimetry to various clinical situations describing how 3D approaches can complement other dose delivery validation approaches already available in the clinic. The applications presented will be selected to inform attendees of the unique features provided by full 3D techniques. Learning Objectives: L. John Schreiner: Background and Motivation Understand recent developments enabling clinically practical 3D dosimetry, Appreciate 3D dosimetry workflow and dosimetry procedures, and Observe select examples from the clinic. Sofie Ceberg: Application to dynamic radiotherapy Observe full dosimetry under dynamic radiotherapy during respiratory motion, and Understand how the measurement of high resolution dose data in an

MO-B-BRB-01: 3D Dosimetry in the Clinic: Background and Motivation

International Nuclear Information System (INIS)

Schreiner, L.

2016-01-01

Full three-dimensional (3D) dosimetry using volumetric chemical dosimeters probed by 3D imaging systems has long been a promising technique for the radiation therapy clinic, since it provides a unique methodology for dose measurements in the volume irradiated using complex conformal delivery techniques such as IMRT and VMAT. To date true 3D dosimetry is still not widely practiced in the community; it has been confined to centres of specialized expertise especially for quality assurance or commissioning roles where other dosimetry techniques are difficult to implement. The potential for improved clinical applicability has been advanced considerably in the last decade by the development of improved 3D dosimeters (e.g., radiochromic plastics, radiochromic gel dosimeters and normoxic polymer gel systems) and by improved readout protocols using optical computed tomography or magnetic resonance imaging. In this session, established users of some current 3D chemical dosimeters will briefly review the current status of 3D dosimetry, describe several dosimeters and their appropriate imaging for dose readout, present workflow procedures required for good dosimetry, and analyze some limitations for applications in select settings. We will review the application of 3D dosimetry to various clinical situations describing how 3D approaches can complement other dose delivery validation approaches already available in the clinic. The applications presented will be selected to inform attendees of the unique features provided by full 3D techniques. Learning Objectives: L. John Schreiner: Background and Motivation Understand recent developments enabling clinically practical 3D dosimetry, Appreciate 3D dosimetry workflow and dosimetry procedures, and Observe select examples from the clinic. Sofie Ceberg: Application to dynamic radiotherapy Observe full dosimetry under dynamic radiotherapy during respiratory motion, and Understand how the measurement of high resolution dose data in an

MO-B-BRB-03: 3D Dosimetry in the Clinic: Validating Special Techniques

International Nuclear Information System (INIS)

Juang, T.

2016-01-01

Full three-dimensional (3D) dosimetry using volumetric chemical dosimeters probed by 3D imaging systems has long been a promising technique for the radiation therapy clinic, since it provides a unique methodology for dose measurements in the volume irradiated using complex conformal delivery techniques such as IMRT and VMAT. To date true 3D dosimetry is still not widely practiced in the community; it has been confined to centres of specialized expertise especially for quality assurance or commissioning roles where other dosimetry techniques are difficult to implement. The potential for improved clinical applicability has been advanced considerably in the last decade by the development of improved 3D dosimeters (e.g., radiochromic plastics, radiochromic gel dosimeters and normoxic polymer gel systems) and by improved readout protocols using optical computed tomography or magnetic resonance imaging. In this session, established users of some current 3D chemical dosimeters will briefly review the current status of 3D dosimetry, describe several dosimeters and their appropriate imaging for dose readout, present workflow procedures required for good dosimetry, and analyze some limitations for applications in select settings. We will review the application of 3D dosimetry to various clinical situations describing how 3D approaches can complement other dose delivery validation approaches already available in the clinic. The applications presented will be selected to inform attendees of the unique features provided by full 3D techniques. Learning Objectives: L. John Schreiner: Background and Motivation Understand recent developments enabling clinically practical 3D dosimetry, Appreciate 3D dosimetry workflow and dosimetry procedures, and Observe select examples from the clinic. Sofie Ceberg: Application to dynamic radiotherapy Observe full dosimetry under dynamic radiotherapy during respiratory motion, and Understand how the measurement of high resolution dose data in an

Radiotherapy Based On α Emitting Radionuclides: Geant4 For Dosimetry And Micro-/Nano-Dosimetry

International Nuclear Information System (INIS)

Guatelli, Susanna

2013-01-01

Possible physics approaches to evaluate the efficacy of TAT are dosimetry, microdosimetry and nanodosimetry. Dosimetry is adequate when mean absorbed dose to a macroscopic target volume is important to understand the biological effect of radiation. General purpose Monte Carlo (MC) codes, based on condensed history approach, are a very useful, cost effective tool to solve dosimetric problems. The condensed history approach is based on the use of multiple scattering theories to calculate the energy losses and angular changes in the direction of the particle. The short α particle range and high LET make the microdosimetric approach more suitable than dosimetry to study TAT from first physics principles, as this approach takes into account the stochastic nature of energy deposition at cellular level

The experience from operation of electronic personal dosimetry system at Dukovany, Temelin and Mochovce NPPs after repair of Siemens dosemeters eliminating false doses

International Nuclear Information System (INIS)

Malysak, J.; Kocvara, S.; Jurochova, B.; Zelenka, Z.; Schacherl, M.; Zrubec, M.; Kaiser, H.

2003-01-01

This presentation summarizes the operational experience of the Electronic Personal Dosimetry Systems installed at Dukovany, Temelin and Mochovce NPPs. The system consists of three basic parts: Electronic personal dosemeters (EPD); Physical layer (HW); Logical layer (SW). Number of false doses before and after correction is presented. This presentation has demonstrated the possibilities of SEOD system and the possibility of easy dose comparison between the individual NPPs after introducing this electronic dosimetry system. Basically, the results of film and electronic dosimetry systems are according to our findings nearly identical. Electronic dosemeter sensitivity to interfering electromagnetic fields is a problem which is easily re-movable. In addition, if we know this problem, these false doses in the SEOD system can be easily revealed (e.g. by investigation of histograms) and repaired

Test study of boron nitride as a new detector material for dosimetry in high-energy photon beams

Science.gov (United States)

Poppinga, D.; Halbur, J.; Lemmer, S.; Delfs, B.; Harder, D.; Looe, H. K.; Poppe, B.

2017-09-01

The aim of this test study is to check whether boron nitride (BN) might be applied as a detector material in high-energy photon-beam dosimetry. Boron nitride exists in various crystalline forms. Hexagonal boron nitride (h-BN) possesses high mobility of the electrons and holes as well as a high volume resistivity, so that ionizing radiation in the clinical range of the dose rate can be expected to produce a measurable electrical current at low background current. Due to the low atomic numbers of its constituents, its density (2.0 g cm-3) similar to silicon and its commercial availability, h-BN appears as possibly suitable for the dosimetry of ionizing radiation. Five h-BN plates were contacted to triaxial cables, and the detector current was measured in a solid-state ionization chamber circuit at an applied voltage of 50 V. Basic dosimetric properties such as formation by pre-irradiation, sensitivity, reproducibility, linearity and temporal resolution were measured with 6 MV photon irradiation. Depth dose curves at quadratic field sizes of 10 cm and 40 cm were measured and compared to ionization chamber measurements. After a pre-irradiation with 6 Gy, the devices show a stable current signal at a given dose rate. The current-voltage characteristic up to 400 V shows an increase in the collection efficiency with the voltage. The time-resolved detector current behavior during beam interrupts is comparable to diamond material, and the background current is negligible. The measured percentage depth dose curves at 10 cm  ×  10 cm field size agreed with the results of ionization chamber measurements within  ±2%. This is a first study of boron nitride as a detector material for high-energy photon radiation. By current measurements on solid ionization chambers made from boron nitride chips we could demonstrate that boron nitride is in principle suitable as a detector material for high-energy photon-beam dosimetry.

Calculation of absorbed dose in water by chemical Fricke dosimetry

International Nuclear Information System (INIS)

Rodrigues, Adenilson Paiva; Meireles, Ramiro Conceicao

2016-01-01

This work is the result of a laboratory activity performed in Radiological Sciences Laboratory (CRL), linked to the State University of Rio de Janeiro (UERJ). This practice aimed to determine the absorbed dose to water, through the primary calibration method called dosimetry Fricke, which consists of ferrous ions (Fe + 2) to ferric (Fe + 3), generated by water radiolysis products which is the structural change of water molecule caused by ionizing radiation. A spectrophotometer was used to extract data for analysis at a wavelength (λ) 304 and 224 nm with function of measuring the absorbance using bottles with irradiated and nonirradiated Fricke solution. (author)

Comparison between Radiology Science Laboratory, Brazil (LCR) and National Research Council, Canada (NRC) of the absorbed dose in water using Fricke dosimetry

International Nuclear Information System (INIS)

Salata, Camila; David, Mariano Gazineu; Almeida, Carlos Eduardo de

2014-01-01

The absorbed dose to water standards for HDR brachytherapy dosimetry developed by the Radiology Science Laboratory, Brazil (LCR) and the National Research Council, Canada (NRC), were compared. The two institutions have developed absorbed dose standards based on the Fricke dosimetry system. There are significant differences between the two standards as far as the preparation and readout of the Fricke solution and irradiation geometry of the holder. Measurements were done at the NRC laboratory using a single Ir-192 source. The comparison of absorbed dose measurements was expressed as the ratio Dw(NRC)/Dw(LCR), which was found to be 1.026. (author)

Thin film tritium dosimetry

Science.gov (United States)

Moran, Paul R.

1976-01-01

The present invention provides a method for tritium dosimetry. A dosimeter comprising a thin film of a material having relatively sensitive RITAC-RITAP dosimetry properties is exposed to radiation from tritium, and after the dosimeter has been removed from the source of the radiation, the low energy electron dose deposited in the thin film is determined by radiation-induced, thermally-activated polarization dosimetry techniques.

Dosimetry in high dose rate endoluminal brachytherapy

International Nuclear Information System (INIS)

Uno, Takashi; Kotaka, Kikuo; Itami, Jun

1994-01-01

In endoluminal brachytherapy for the tracheobronchial tree, esophagus, and bile duct, a reference point for dose calculation has been often settled at 1 cm outside from the middle of source travel path. In the current study, a change in the ratio of the reference point dose on the convex to concave side (Dq/Dp) was calculated, provided the source travel path bends as is the case in most endoluminal brachytherapies. Point source was presumed to move stepwise at 1 cm interval from 4 to 13 locations. Retention time at each location was calculated by personal computer so as to deliver equal dose at 1 cm from the linear travel path. With the retention time remaining constant, the change of Dq/Dp was assessed by bending the source travel path. Results indicated that the length of the source travel path and radius of its curve influenced the pattern of change in Dq/Dp. Therefore, it was concluded that the difference in reference dose on the convex and concave side of the curved path is not negligible under certain conditions in endoluminal brachytherapy. In order to maintain the ratio more than 0.9, relatively greater radius was required when the source travel path was decreased. (author)

Using the OSL single-aliquot regenerative-dose protocol with quartz extracted from building materials in retrospective dosimetry

DEFF Research Database (Denmark)

Bøtter-Jensen, L.; Solongo, S.; Murray, A.S.

2000-01-01

We report on the application of the single-aliquot regenerative-dose (SAR) protocol to the optically stimulated luminescence signal from quartz extracted from fired bricks acid unfired mortar in retrospective dosimetry. The samples came from a radioactive materials storage facility, with ambient...... dose rates of about 0.1 mGy/h. A detailed dose-depth profile was analysed from one brick, and compared with dose records from area TL dosemeters. Small-aliquot dose-distributions were analysed from the mortar samples; one associated with the exposed brick, and one from a remote site exposed only...

In vivo dosimetry of high-dose fractionated irradiation in an experimental set-up with rats

Energy Technology Data Exchange (ETDEWEB)

Fortan, L; Van Hecke, H; Van Duyse, B; De Neve, W; De Meerleer, B [Ghent Rijksuniversiteit (Belgium). Kliniek voor Radiotherapie en Kerngeneeskunde; Pattyn, P; Van Renthergem, K [Ghent University (Belgium). Dept. of Surgery

1995-12-01

The feasibility to irradiate a limited section of a rat abdomen with well-defined edges was assessed. Because of the relative small volume involved, in vivo dosimetry with TLDs was necessary in providing us information about the accuracy of the irradiation method. Three to five days prior to the start of the radiotherapy treatment, two plastic strips - each containing a TLD-dosimeter (Harshaw TLD10 LiF rods, 1 mm dia x 6 mm) sealed in polyethylene tubing, and a lead bean - were implanted in the rat abdomen. The plastic strips made a closed loop around the bowel, through the mesenterium, and were fixed with a single stitch on the inner abdominal wall. One loop was made in the hepatic area; another was made in the lower abdomen, around the rectosigmoid. Conscious animals were irradiated using a purpose-build plexi-holder, with rear legs immobilised to avoid longitudinal movements. The implanted lead beans enabled us to simulate the rat prior to each radiation session. This way, the radiation field could be set up individually for each rat, in such way that the rectosigmoid area received full dose and the hepatic area received no irradiation dose at all. Irradiation was carried out, using 5 MV photons of a linear accelerator. Fifteen animals per group were irradiated according a conventional (2.0 Gy / fraction; 5 fractions / week) or a hyperfractionated (1.6 Gy / fraction; 2 daily fractions; 5 days / week) schedule, with different total doses. Prior to implantation, TLDs were individually calibrated and checked for stability. After removal from the abdomen . TLDs were tested again for accuracy. TLDs with an unacceptable read-out curve were rejected (about 2 to 4 TLDs per group of 15). The obtained accumulated doses - as determined by TLD read-outs-were comparable to the theoretical doses, indicating that fractionated radiation of small fields, with well defined mark off, in rats is feasible.

In vivo dosimetry of high-dose fractionated irradiation in an experimental set-up with rats

International Nuclear Information System (INIS)

Fortan, L.; Van Hecke, H.; Van Duyse, B.; De Neve, W.; De Meerleer, B.; Pattyn, P.; Van Renthergem, K.

1995-01-01

The feasibility to irradiate a limited section of a rat abdomen with well-defined edges was assessed. Because of the relative small volume involved, in vivo dosimetry with TLDs was necessary in providing us information about the accuracy of the irradiation method. Three to five days prior to the start of the radiotherapy treatment, two plastic strips - each containing a TLD-dosimeter (Harshaw TLD10 LiF rods, 1 mm dia x 6 mm) sealed in polyethylene tubing, and a lead bean - were implanted in the rat abdomen. The plastic strips made a closed loop around the bowel, through the mesenterium, and were fixed with a single stitch on the inner abdominal wall. One loop was made in the hepatic area; another was made in the lower abdomen, around the rectosigmoid. Conscious animals were irradiated using a purpose-build plexi-holder, with rear legs immobilised to avoid longitudinal movements. The implanted lead beans enabled us to simulate the rat prior to each radiation session. This way, the radiation field could be set up individually for each rat, in such way that the rectosigmoid area received full dose and the hepatic area received no irradiation dose at all. Irradiation was carried out, using 5 MV photons of a linear accelerator. Fifteen animals per group were irradiated according a conventional (2.0 Gy / fraction; 5 fractions / week) or a hyperfractionated (1.6 Gy / fraction; 2 daily fractions; 5 days / week) schedule, with different total doses. Prior to implantation, TLDs were individually calibrated and checked for stability. After removal from the abdomen . TLDs were tested again for accuracy. TLDs with an unacceptable read-out curve were rejected (about 2 to 4 TLDs per group of 15). The obtained accumulated doses - as determined by TLD read-outs-were comparable to the theoretical doses, indicating that fractionated radiation of small fields, with well defined mark off, in rats is feasible

From nGy to MGy - new TL dosimetry of complex radiation at high-energy accelerators and thermonuclear fusion facilities

International Nuclear Information System (INIS)

Obryk, B.; Bilski, P.; Budzanowski, M.; Olko, P.

2011-01-01

One of the well known advantages of thermoluminescence (TL) detectors made of lithium fluoride doped with magnesium, copper and phosphorus (LiF:Mg,Cu,P) is their very high sensitivity to ionizing radiation. LiF:Mg,Cu,P detectors enable measurements of radiation doses from tens of nano grays up to a few kilo grays, when the total saturation of the signal of the so-called main dosimetric peak (at about 220 C. degrees) occurs. In 2006 for the first time we observed unprecedented high-temperature emission of LiF detectors heated to temperatures up to 600 C. degrees, after exposures to radiation doses ranging from 1 kGy to 1 MGy. For quantification of the glow curve shape changes of LiF:Mg,Cu,P detectors in this range of doses and determination of the absorbed dose, the high temperature coefficient (UHTR) was defined. This newly established dosimetric method was tested in a range of radiation qualities, such as gamma radiation, electron and proton beams, thermal neutron fields and in high-energy mixed fields around the SPS and PS accelerators at CERN. A number of dosimetric sets with LiF:Mg,Cu,P detectors are currently installed around the LHC at CERN. The new method for ultra-high dose range monitoring with a single LiF:Mg,Cu,P detector, which is capable of covering at least twelve orders of magnitude of doses, can be used for dosimetry at high energy accelerators and has great potential for accident dosimetry in particular. (authors)

Dose planning with comparison to in vivo dosimetry for epithermal neutron irradiation of the dog brain

International Nuclear Information System (INIS)

Seppaelae, Tiina; Auterinen, Iiro; Aschan, Carita; Seren, Tom; Benczik, Judit; Snellman, Marjatta; Huiskamp, Rene; Ramadan, Usama Abo; Kankaanranta, Leena; Joensuu, Heikki; Savolainen, Sauli

2002-01-01

Boron neutron capture therapy (BNCT) is an experimental type of radiotherapy, presently being used to treat glioblastoma and melanoma. To improve patient safety and to determine the radiobiological characteristics of the epithermal neutron beam of Finnish BNCT facility (FiR 1) dose-response studies were carried on the brain of dogs before starting the clinical trials. A dose planning procedure was developed and uncertainties of the epithermal neutron-induced doses were estimated. The accuracy of the method of computing physical doses was assessed by comparing with in vivo dosimetry. Individual radiation dose plans were computed using magnetic resonance images of the heads of 15 Beagle dogs and the computational model of the FiR 1 epithermal neutron beam. For in vivo dosimetry, the thermal neutron fluences were measured using Mn activation foils and the gamma-ray doses with MCP-7s type thermoluminescent detectors placed both on the skin surface of the head and in the oral cavity. The degree of uncertainty of the reference doses at the thermal neutron maximum was estimated using a dose-planning program. The estimated uncertainty (±1 standard deviation) in the total physical reference dose was ±8.9%. The calculated and the measured dose values agreed within the uncertainties at the point of beam entry. The conclusion is that the dose delivery to the tissue can be verified in a practical and reliable fashion by placing an activation dosimeter and a TL detector at the beam entry point on the skin surface with homogeneous tissues below. However, the point doses cannot be calculated correctly in the inhomogeneous area near air cavities of the head model with this type of dose-planning program. This calls for attention in dose planning in human clinical trials in the corresponding areas

Personnel neutron dose assessment upgrade: Volume 1, Personnel neutron dosimetry assessment: [Final report

International Nuclear Information System (INIS)

Hadlock, D.E.; Brackenbush, L.W.; Griffith, R.V.; Hankins, D.E.; Parkhurst, M.A.; Stroud, C.M.; Faust, L.G.; Vallario, E.J.

1988-07-01

This report provides guidance on the characteristics, use, and calibration criteria for personnel neutron dosimeters. The report is applicable for neutrons with energies ranging from thermal to less than 20 MeV. Background for general neutron dosimetry requirements is provided, as is relevant federal regulations and other standards. The characteristics of personnel neutron dosimeters are discussed, with particular attention paid to passive neutron dosimetry systems. Two of the systems discussed are used at DOE and DOE-contractor facilities (nuclear track emulsion and thermoluminescent-albedo) and another (the combination TLD/TED) was recently developed. Topics discussed in the field applications of these dosimeters include their theory of operation, their processing, readout, and interpretation, and their advantages and disadvantages for field use. The procedures required for occupational neutron dosimetry are discussed, including radiation monitoring and the wearing of dosimeters, their exchange periods, dose equivalent evaluations, and the documenting of neutron exposures. The coverage of dosimeter testing, maintenance, and calibration includes guidance on the selection of calibration sources, the effects of irradiation geometries, lower limits of detectability, fading, frequency of calibration, spectrometry, and quality control. 49 refs., 6 figs., 8 tabs

Radiation dose during tomography of the petrous bone. Experimental investigations with film dosimetry on an Alderson phantom

Energy Technology Data Exchange (ETDEWEB)

Grehn, S.

1988-06-01

Using filmdosimetry and an Alderson skull phantom, the iso-dose distribution during tomography of the petrous bone was investigated. We were particularly concerned with the radiation dose to the lens of the eye, the critical organ in the skull, and to the inner ear, using different types of examination and various positions of the skull. The choice of suitable film material and standardisation against TLD measurements is crucial for the accuracy of film dosimetry, allowing for correction of film blackening in relation to varying energies. Tomography of the petrous bone in the prone position produced a reduction in radiation dose to the eye to only 1 to 4% of the dose incident on the occiput. In this way, and using high definition screen and grinds, it is possible to obtain optimal tomographic images despite drastic reduction of the scattered radiation to the eye. Radiation dose to the inner ear is greatly below any significant somatic dose, irrespective of projection or technique. Special measures to reduce radiation to the inner ear are neither effective nor sensible.

Workshop on dosimetry for radon and radon daughters

International Nuclear Information System (INIS)

Turner, J.E.; Holoway, C.F.; Loebl, A.S.

1978-05-01

Emphasis is placed on the dosimetry for radon and daughters, rather than on monitoring and instrumentation. The objectives of the meeting were to exchange scientific information, to identify problem areas in radon-daughter dosimetry, and to make any observations or recommendations by the participants through issuance of this report. The discussion topics included the history of dosimetry for radon and daughters, human data, aerosols, deposition and movement in the respiratory tract, dose calculations, dose-to-working-level-month (WLM) conversion factors, animal experiments, and the development of regulations and remedial criteria for reducing population exposures to radon daughters. This report contains a summary of Workshop discussions plus individual statements contributed by several of the participants. The outstanding problem areas from the standpoint of dosimetry appear to involve the appropriate lung organ mass to be used (average lung-tissue dose vs. high-level local dose); recognition of the discrete, rather than continuous, structure of the mucus; lack of knowledge about lung clearance; the variability of dose with the degree of disequilibrium and the unattached fraction of radon daughters for a given WLM; and questions about the character of uranium mine atmospheres actually breathed in the older mines from which much of the epidemiological information originates. The development of criteria for taking remedial action to reduce exposures involves additional concerns of basing long-term risk assessment on short-term sampling and applying WLM data for miners to general populations

Dosimetry system 1986

International Nuclear Information System (INIS)

Woolson, William A.; Egbert, Stephen D.; Gritzner, Michael L.

1987-01-01

the new dosimetry. The experience gained by the use of this prototype paved the way for an improved system called Dosimetry System 1986 (DS86), which incorporated further developments in dosimetry and treated a more extensive set of survivors in the RERF data base. The fourth joint US-Japan dosimetry workshop, held in Hiroshima on 16 and 17 March 1986, reviewed the results and findings of the research to assess the A-bomb dose estimates and their incorporation into DS86. As a result, the US-Japan A-bomb radiation dosimetry committees formally approved replacement of T65D with DS86 for use by RERF for computation of doses to A-bomb survivors. The purpose of this chapter is to provide a description of DS86

In vivo dose evaluation during gynaecological radiotherapy using L-alanine/ESR dosimetry

International Nuclear Information System (INIS)

Burg Rech, Amanda; Baffa, Oswaldo; Barbi, Gustavo Lazzaro; Almeida Ventura, Luiz Henrique; Silva Guimaraes, Flavio; Oliveira, Harley Francisco

2014-01-01

The dose delivered by in vivo 3-D external beam radiation therapy (EBRT) was verified with L-alanine/electron spin resonance (ESR) dosimetry for patients diagnosed with gynaecological cancer. Measurements were performed with an X-band ESR spectrometer. Dosemeters were positioned inside the vaginal cavity with the assistance of an apparatus specially designed for this study. Previous phantom studies were performed using the same conditions as in the in vivo treatment. Four patients participated in this study during 20-irradiation sessions, giving 220 dosemeters to be analysed. The doses were determined with the treatment planning system, providing dose confirmation. The phantom study resulted in a deviation between -2.5 and 2.1 %, and for the in vivo study a deviation between -9.2 and 14.2 % was observed. In all cases, the use of alanine with ESR was effective for dose assessment, yielding results consistent with the values set forth in the International Commission on Radiation Units and Measurements (ICRU) reports. (authors)

Bayesian Methods for Radiation Detection and Dosimetry

CERN Document Server

Groer, Peter G

2002-01-01

We performed work in three areas: radiation detection, external and internal radiation dosimetry. In radiation detection we developed Bayesian techniques to estimate the net activity of high and low activity radioactive samples. These techniques have the advantage that the remaining uncertainty about the net activity is described by probability densities. Graphs of the densities show the uncertainty in pictorial form. Figure 1 below demonstrates this point. We applied stochastic processes for a method to obtain Bayesian estimates of 222Rn-daughter products from observed counting rates. In external radiation dosimetry we studied and developed Bayesian methods to estimate radiation doses to an individual with radiation induced chromosome aberrations. We analyzed chromosome aberrations after exposure to gammas and neutrons and developed a method for dose-estimation after criticality accidents. The research in internal radiation dosimetry focused on parameter estimation for compartmental models from observed comp...

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

International Nuclear Information System (INIS)

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

2006-01-01

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

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

Energy Technology Data Exchange (ETDEWEB)

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

2006-12-20

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

Recent progress in application of JAERI alanine/ESR dosimetry system

International Nuclear Information System (INIS)

Kojima, T.

1995-01-01

Feasibility studies of application of JAERI alanine/ESR dosimetry system were performed on radiotherapy level dosimetry, low dose-rate dosimetry for residual life estimation of cable insulators used in nuclear power facilities, and dose monitoring for electron processing. (author)

Double dosimetry procedures for the determination of occupational effective dose in interventional radiology

International Nuclear Information System (INIS)

Jaervinen, H.; Buls, N.; Clerinx, P.; Miljanic, S.; Ranogajec-Komor, M.; Nikodemova, D.; D'Errico, F.

2008-01-01

Full text: In interventional radiology, for an accurate determination of occupational effective dose, measurements with two dosemeters ('double dosimetry', DD) have been recommended, one dosemeter located above and one under the protective apron. In this paper, based on an extensive literature search, the most recent algorithms developed for the determination of effective dose from the dosimeter readings have been compared for a few practical interventional procedures. Recommendations on the practices and algorithms are given on the basis of the results. For the comparison of algorithms, dosemeter readings and the effective dose were obtained both experimentally and by calculation. Further, data from published Monte Carlo calculations have been applied. The literature review has indicated that very few regulations for DD exist and the DD practices have not been harmonized. There is no firm consensus on the most suitable calculation algorithms. Single dosemeter (SD) measurements are still mostly used for the calculation of effective dose. Most DD and SD algorithms overestimate effective dose significantly, sometimes by over ten times. However, SD algorithms can significantly underestimate effective dose in certain interventional radiology conditions. Due to the possibility of underestimating effective dose, DD is generally recommended. The results suggest that there might not be a single DD algorithm which would be optimum for all interventional radiology procedures. However, the selection of a precise DD algorithm for each individual condition is not practical and compromises must be made. For accurate personnel dosimetry, the accuracy of the algorithm selected should be tested for typical local interventional radiology condition. Personnel dosemeters should be used in the recommended positions. The dosemeter above the apron should be on a collar and its reading also used to assess the risk of lens injuries. The dosemeter under the apron can be on the chest or

Light-water-reactor pressure-vessel surveillance dosimetry using solid-state track recorders

International Nuclear Information System (INIS)

Ruddy, F.H.; Roberts, J.H.; Gold, R.; Preston, C.C.

1983-07-01

The accumulation of neutron dose by the pressure vessel of an operating nuclear power plant results in damage in the form of steel embrittlement. In order to ascertain the safe operating lifetime of the reactor pressure vessel, dosimetric measurements must be made to evaluate the neutron dose to the pressure vessel and relate this dose to the cumulative radiation damage. Advanced dosimetry techniques are being evaluated for surveillance of operating reactors. Solid-state track recorder (SSTR) techniques are included among these advanced dosimetry techniques. Described herein are low neutron fluence calibration and standardization measurements that are being carried out in pressure vessel mockup benchmark neutron fields in the USA, Belgium, and England. In addition, high fluence SSTR dosimetry capsules have been irradiated with metallurgical specimens in a pressure vessel mockup facility. The design and deployment of advances SSTR dosimetry capsules in operating power reactors are also described

Management system of personnel dosimetry based on ISO 9001:2008 for medical diagnostic

International Nuclear Information System (INIS)

Queiroz, Carlos E.B.; Gerber Junior, Walmoli; Jahn, Tiago R.; Hahn, Tiago T.; Fontana, Thiago S.; Bolzan, Vagner

2013-01-01

MDose is a computer management system of personal dosimetry in diagnostic radiology services physician based on ISO 9001:9008 management system. According to Brazilian law all service radiology should implement a control of personal dosimetry in addition to radiation doses greater than 1.5 mSv/year service should do research of high dose, which is to identify the causes the resulting dose increase professional. This work is based on the use of the PDCA cycle in a JAVA software developed as a management method in the analysis of high doses in order to promote systematic and continuous improvement within the organization of radiological protection of workers

Investigating the feasibility of 3D dosimetry in the RPC IMRT H and N phantom

Energy Technology Data Exchange (ETDEWEB)

Sakhalkar, H S; Sterling, D [Department of Radiation Oncology Physics, Duke University Medical Center, Durham, NC (United States); Adamovics, J [Department of Chemistry and Biology, Rider University, Lawrenceville, NJ (United States); Ibbott, G [Department of Radiation Physics, M. D. Anderson Cancer Center, Houston, Tx (United States); Oldham, M, E-mail: mark.oldham@duke.edu

2009-05-01

An urgent requirement for 3D dosimetry has been recognized because of high failure rate ({approx}25%) in RPC credentialing, which relies on point and 2D dose measurements. Comprehensive 3D dosimetry is likely to resolve more errors and improve IMRT quality assurance. This work presents an investigation of the feasibility of PRESAGE/optical-CT 3D dosimetry in the Radiologic Physics Center (RPC) IMRT H and N phantom. The RPC H and N phantom (with standard and PRESAGE dosimetry inserts alternately) was irradiated with the same IMRT plan. The TLD and EBT film measurement data from standard insert irradiation was provided by RPC. The 3D dose measurement data from PRESAGE insert irradiation was readout using the OCTOPUS{sup TM} 5X optical-CT scanner at Duke. TLD, EBT and PRESAGE dose measurements were inter-compared with Eclipse calculations to evaluate consistency of planning and delivery. Results showed that the TLD point dose measurements agreed with Eclipse calculations to within 5% dose-difference. Relative dose comparison between Eclipse dose, EBT dose and PRESAGE dose was conducted using profiles and gamma comparisons (4% dose-difference and 4 mm distance-to-agreement). Profiles showed good agreement between measurement and calculation except along steep dose gradient regions where Eclipse modelling might be inaccurate. Gamma comparisons showed that the measurement and calculation showed good agreement (>96%) if edge artefacts in measurements are ignored. In conclusion, the PRESAGE/optical-CT dosimetry system was found to be feasible as an independent dosimetry tool in the RPC IMRT H and N phantom.

Investigating the feasibility of 3D dosimetry in the RPC IMRT H and N phantom

International Nuclear Information System (INIS)

Sakhalkar, H S; Sterling, D; Adamovics, J; Ibbott, G; Oldham, M

2009-01-01

An urgent requirement for 3D dosimetry has been recognized because of high failure rate (∼25%) in RPC credentialing, which relies on point and 2D dose measurements. Comprehensive 3D dosimetry is likely to resolve more errors and improve IMRT quality assurance. This work presents an investigation of the feasibility of PRESAGE/optical-CT 3D dosimetry in the Radiologic Physics Center (RPC) IMRT H and N phantom. The RPC H and N phantom (with standard and PRESAGE dosimetry inserts alternately) was irradiated with the same IMRT plan. The TLD and EBT film measurement data from standard insert irradiation was provided by RPC. The 3D dose measurement data from PRESAGE insert irradiation was readout using the OCTOPUS TM 5X optical-CT scanner at Duke. TLD, EBT and PRESAGE dose measurements were inter-compared with Eclipse calculations to evaluate consistency of planning and delivery. Results showed that the TLD point dose measurements agreed with Eclipse calculations to within 5% dose-difference. Relative dose comparison between Eclipse dose, EBT dose and PRESAGE dose was conducted using profiles and gamma comparisons (4% dose-difference and 4 mm distance-to-agreement). Profiles showed good agreement between measurement and calculation except along steep dose gradient regions where Eclipse modelling might be inaccurate. Gamma comparisons showed that the measurement and calculation showed good agreement (>96%) if edge artefacts in measurements are ignored. In conclusion, the PRESAGE/optical-CT dosimetry system was found to be feasible as an independent dosimetry tool in the RPC IMRT H and N phantom.

The 1st Nuclear Test in the former USSR of 29 August 1949: Comparison of individual dose estimates by modeling with EPR retrospective dosimetry and luminescence retrospective dosimetry data for Dolon village, Kazakhstan

Energy Technology Data Exchange (ETDEWEB)

Stepanenko, V.F. [Medical Radiological Research Center of RAMS, 4 Korolev Str., Obninsk 249036 (Russian Federation); Research Institute for Radiation Biology and Medicine, Hiroshima University, 1-2-3 Kasumi 1-2-3, Minami-ku, Hiroshima 734-8553 (Japan)], E-mail: mrrc@obninsk.ru; Hoshi, M. [Research Institute for Radiation Biology and Medicine, Hiroshima University, 1-2-3 Kasumi 1-2-3, Minami-ku, Hiroshima 734-8553 (Japan); Ivannikov, A.I. [Medical Radiological Research Center of RAMS, 4 Korolev Str., Obninsk 249036 (Russian Federation); Research Institute for Radiation Biology and Medicine, Hiroshima University, 1-2-3 Kasumi 1-2-3, Minami-ku, Hiroshima 734-8553 (Japan); Bailiff, I.K. [Luminescence Dating and Dosimetry Laboratory, University of Durham, South Road, Durham, DHI 3LE (United Kingdom); Zhumadilov, K. [Research Institute for Radiation Biology and Medicine, Hiroshima University, 1-2-3 Kasumi 1-2-3, Minami-ku, Hiroshima 734-8553 (Japan); Skvortsov, V.G. [Medical Radiological Research Center of RAMS, 4 Korolev Str., Obninsk 249036 (Russian Federation); Argembaeva, R. [Scientifical Research Institute for Radiation Medicine, 258, Gagarina Str., P.B. 49, Semipalatinsk 490026 (Kazakhstan); Tsyb, A.F. [Medical Radiological Research Center of RAMS, 4 Korolev Str., Obninsk 249036 (Russian Federation)

2007-07-15

Three methods of individual dose reconstruction, namely dose calculations based on the available archive data and on the individual questioning of inhabitants, EPR dosimetry in human tooth enamel, and retrospective luminescence dosimetry (RLD) with quartz inclusions in the bricks were applied for assessment of accumulated external doses in Dolon village (Kazakhstan), which is one of the most affected settlements as a result of 29.08.1949 nuclear test at Semipalatinsk nuclear test site. Dose values obtained by EPR and RLD methods were compared with computed dose values. The available data on soil contamination with {sup 137}Cs and {sup 239+240}Pu in the vicinity and inside Dolon village were used for interpretation of the results of comparison. Based on a calculated value of 2260 mGy for the dose in the air along the central axis of the trace located NW of Dolon, the doses in the air over whole village and for the south-eastern part of the village containing the RLD sampling points were estimated as 775{+-}40 and 645{+-}70mGy, respectively, the latter correlates well with the RLD dose value of 460{+-}92mGy. The 'upper level' of the mean 'shielding and behavior' factor of dose reduction for inhabitants of Dolon village was estimated as 0.28{+-}0.07; this was performed by comparing the individual EPR tooth enamel doses with the calculated mean dose for the settlement. The individual dose estimates by EPR dosimetry were compared with individual dose values obtained by modeling. Uncertainties of the calculated individual doses were evaluated using Monte Carlo simulations. The individual dose estimates by EPR method are lower in comparison with mean computed doses and with RLD data, but they are in a good consistency with computed individual dose values in Dolon village based on the results of individual questioning with account of individual 'shielding and behavior' factors.

The 1st Nuclear Test in the former USSR of 29 August 1949: Comparison of individual dose estimates by modeling with EPR retrospective dosimetry and luminescence retrospective dosimetry data for Dolon village, Kazakhstan

International Nuclear Information System (INIS)

Stepanenko, V.F.; Hoshi, M.; Ivannikov, A.I.; Bailiff, I.K.; Zhumadilov, K.; Skvortsov, V.G.; Argembaeva, R.; Tsyb, A.F.

2007-01-01

Three methods of individual dose reconstruction, namely dose calculations based on the available archive data and on the individual questioning of inhabitants, EPR dosimetry in human tooth enamel, and retrospective luminescence dosimetry (RLD) with quartz inclusions in the bricks were applied for assessment of accumulated external doses in Dolon village (Kazakhstan), which is one of the most affected settlements as a result of 29.08.1949 nuclear test at Semipalatinsk nuclear test site. Dose values obtained by EPR and RLD methods were compared with computed dose values. The available data on soil contamination with 137 Cs and 239+240 Pu in the vicinity and inside Dolon village were used for interpretation of the results of comparison. Based on a calculated value of 2260 mGy for the dose in the air along the central axis of the trace located NW of Dolon, the doses in the air over whole village and for the south-eastern part of the village containing the RLD sampling points were estimated as 775±40 and 645±70mGy, respectively, the latter correlates well with the RLD dose value of 460±92mGy. The 'upper level' of the mean 'shielding and behavior' factor of dose reduction for inhabitants of Dolon village was estimated as 0.28±0.07; this was performed by comparing the individual EPR tooth enamel doses with the calculated mean dose for the settlement. The individual dose estimates by EPR dosimetry were compared with individual dose values obtained by modeling. Uncertainties of the calculated individual doses were evaluated using Monte Carlo simulations. The individual dose estimates by EPR method are lower in comparison with mean computed doses and with RLD data, but they are in a good consistency with computed individual dose values in Dolon village based on the results of individual questioning with account of individual 'shielding and behavior' factors

High dose gamma-ray standard

International Nuclear Information System (INIS)

Macrin, R.; Moraru, R.

1999-01-01

The high gamma-ray doses produced in a gamma irradiator are used, mainly, for radiation processing, i.e. sterilization of medical products, processing of food, modifications of polymers, irradiation of electronic devices, a.s.o. The used absorbed doses depend on the application and cover the range 10 Gy to 100 MGy. The regulations in our country require that the response of the dosimetry systems, used for the irradiation of food and medical products, be calibrated and traceable to the national standards. In order to be sure that the products receive the desired absorbed dose, appropriate dosimetric measurements must be performed, including the calibration of the dosemeters and their traceability to the national standards. The high dose gamma-ray measurements are predominantly based on the use of reference radiochemical dosemeters. Among them the ferrous sulfate can be used as reference dosemeter for low doses (up to 400 Gy) but due to its characteristics it deserves to be considered a standard dosemeter and to be used for transferring the conventional absorbed dose to other chemical dosemeters used for absorbed doses up to 100 MGy. The study of the ferrous sulfate dosemeter consisted in preparing many batches of solution by different operators in quality assurance conditions and in determining for all batches the linearity, the relative intrinsic error, the repeatability and the reproducibility. The principal results are the following: the linear regression coefficient: 0.999, the relative intrinsic error: max.6 %, the repeatability (for P* = 95 %): max.3 %, the reproducibility (P* = 95%): max.5 %. (authors)

Hanford internal dosimetry program manual

International Nuclear Information System (INIS)

Carbaugh, E.H.; Sula, M.J.; Bihl, D.E.; Aldridge, T.L.

1989-10-01

This document describes the Hanford Internal Dosimetry program. Program Services include administrating the bioassay monitoring program, evaluating and documenting assessments of internal exposure and dose, ensuring that analytical laboratories conform to requirements, selecting and applying appropriate models and procedures for evaluating internal radionuclide deposition and the resulting dose, and technically guiding and supporting Hanford contractors in matters regarding internal dosimetry. 13 refs., 16 figs., 42 tabs

Personnel dosimetry methods introduced in the Czechoslovak national laboratories

International Nuclear Information System (INIS)

Trousil, J.; Singer, J.; Kokta, L.; Prouza, Z.

1979-01-01

Personnel dosimetry methods are described that were developed in the Institute for Research, Production and Application of Radioisotopes and that have been or will be introduced in the national personnel dosimetry service. In Czechoslovakia, workers exposed to a radiation risk are divided into two groups, according to the level of the risk. The criterion is the possibility of exceeding one tenth of the MPD. For the higher risk group, a complex dose meter is usually used for dosimetry of photon and beta radiation; it contains a film dose meter and a radiothermoluminescent (RTL) glass dose meter. The RTL glass dose meter also serves as an accident dose meter. For neutron dosimetry, a dose meter comprising a solid-state track detector in combination with fissionable foils has been introduced. For accident dosimetry, a silicon diode of Czechoslovak production is used. For the lower risk group, only the introduction of an RTL dose meter is foreseen. There will be a three month control period; for neutron dosimetry, the track detector in combination with fissionable foils is retained. For measurements of hand doses, a themoluminescent ring dose meter has been introduced. The dose meters are described, giving information on the types of detectors employed, measurement techniques and descriptions of the basic characteristics of the instruments, their basic dosimetric parameters and the dose and energy ranges which can be measured. The results of international comparisons are presented; these have served to confirm the measurement precision. In conclusion, some questions of dose-meter calibration are summarized, and the problems of dose measurement in mixed fields of neutrons and gamma rays are discussed. (author)

Plasma Doping - Enabling Technology for High Dose Logic and Memory Applications

International Nuclear Information System (INIS)

Miller, T.; Godet, L.; Papasouliotis, G. D.; Singh, V.

2008-01-01

As logic and memory device dimensions shrink with each generation, there are more high dose implants at lower energies. Examples include dual poly gate (also referred to as counter-doped poly), elevated source drain and contact plug implants. Plasma Doping technology throughput and dopant profile benefits at these ultra high dose and lower energy conditions have been well established [1,2,3]. For the first time a production-worthy plasma doping implanter, the VIISta PLAD tool, has been developed with unique architecture suited for precise and repeatable dopant placement. Critical elements of the architecture include pulsed DC wafer bias, closed-loop dosimetry and a uniform low energy, high density plasma source. In this paper key performance metrics such as dose uniformity, dose repeatability and dopant profile control will be presented that demonstrate the production-worthiness of the VIISta PLAD tool for several high dose applications.

Radiochromic film dosimetry

International Nuclear Information System (INIS)

Xu Zhiyong

2002-01-01

Radiochromic film dosimetry was developed to measure ionization irradiation dose for industry and medicine. At this time, there are no comprehensive guideline on the medical application, calibration method and densitometer system for medicine. The review gives update on Radiochromic film dosimetry used for medicine, including principles, film model and material, characteristics, calibration method, scanning densitometer system and medical application

A practical three-dimensional dosimetry system for radiation therapy

International Nuclear Information System (INIS)

Guo Pengyi; Adamovics, John; Oldham, Mark

2006-01-01

There is a pressing need for a practical three-dimensional (3D) dosimetry system, convenient for clinical use, and with the accuracy and resolution to enable comprehensive verification of the complex dose distributions typical of modern radiation therapy. Here we introduce a dosimetry system that can achieve this challenge, consisting of a radiochromic dosimeter (PRESAGE trade mark sign ) and a commercial optical computed tomography (CT) scanning system (OCTOPUS trade mark sign ). PRESAGE trade mark sign is a transparent material with compelling properties for dosimetry, including insensitivity of the dose response to atmospheric exposure, a solid texture negating the need for an external container (reducing edge effects), and amenability to accurate optical CT scanning due to radiochromic optical contrast as opposed to light-scattering contrast. An evaluation of the performance and viability of the PRESAGE trade mark sign /OCTOPUS, combination for routine clinical 3D dosimetry is presented. The performance of the two components (scanner and dosimeter) was investigated separately prior to full system test. The optical CT scanner has a spatial resolution of ≤1 mm, geometric accuracy within 1 mm, and high reconstruction linearity (with a R 2 value of 0.9979 and a standard error of estimation of ∼1%) relative to independent measurement. The overall performance of the PRESAGE trade mark sign /OCTOPUS system was evaluated with respect to a simple known 3D dose distribution, by comparison with GAFCHROMIC[reg] EBT film and the calculated dose from a commissioned planning system. The 'measured' dose distribution in a cylindrical PRESAGE trade mark sign dosimeter (16 cm diameter and 11 cm height) was determined by optical-CT, using a filtered backprojection reconstruction algorithm. A three-way Gamma map comparison (4% dose difference and 4 mm distance to agreement), between the PRESAGE trade mark sign , EBT and calculated dose distributions, showed full agreement in

Report on external occupational dosimetry in Canada

International Nuclear Information System (INIS)

1995-12-01

In light of the new recommendations of the ICRP in Report 60 on dose quantities and dose limits, this working group was set up to examine the implications for external dosimetry in Canada. The operational quantities proposed by the ICRU are discussed in detail with regard to their applicability in Canada. The current occupational dosimetry services available in Canada are described as well as the several performance intercomparisons that have been carried out within the country as well as internationally. Recommendations are given with respect to standards for dosimetry, including accuracy and precision. More practical advice is given on the choice of dosimeter to use for external dosimetry, frequency of monitoring, and who should be monitored. Specific advice is given on the monitoring of pregnant workers and problem of non-uniform irradiation. Accident and emergency dosimetry are dealt with briefly. Suggestions are given regarding record keeping both for employers and for the national dose registry. 48 refs., 6 tabs., 1 fig

Dosimetry study for electron beam irradiation in radiation processing

International Nuclear Information System (INIS)

Sunaga, Hiromi; Haruyama, Yasuyuki; Takizawa, Haruki; Kojima, Takuji; Yotsumoto, Keiichi

1995-01-01

For certain critical applications such as medical device sterilization and food irradiation, accurate calibration of electron energy and absorbed dose is required to assure the quality of irradiated products. To meet this requirement, TRCRE, JAERI has carried out research and development on high dose radiation dosimetry for electron beams in the energy range used in radiation processing (0.15 - 3.0 MeV). JAERI has developed a simultaneous electron beam energy and dosimeter calibration system that consist of a total absorption calorimeter, an electron current density meter, and a stacked thin-film dosimeter set. For low energy electrons, where it is important to measure the depth-dose profile in materials with high depth resolution, we studied the feasibility of a method using Gafchromic film dosimeters. This film, which has an 8-μm thick sensitive layer, is combined with a stepped array of absorber films of the same thickness to produce a high-resolution depth-dose profile on the Gafchromic film. The depth-dose profile obtained in this manner has about five times greater resolution than conventional radiochromic film dosimetry. (author)

Commissioning dosimetry at SINAGAMA irradiation facility

International Nuclear Information System (INIS)

Noriah Mod Ali; Hasan Sham; Taiman Kadni

2000-01-01

Dose mapping is one of the important factors in the commissioning of the irradiation plant. Comparison of the dose distribution obtained through the dose mapping exercise carried out since 1991 for Sinagama plant are described in this paper. It is aimed to confirmed the need for a thorough dose-mapping before the plant can be proceed with routine irradiation. The dose measurement was performed using a routine ceric-cerous dosimeter, supplied by the High Dose Dosimetry Laboratory, SSDL. The quality assurance of these service was maintain and verify through regular participation in dose intercomparison organised by the IAEA

Biological and clinical dosimetry, July 1, 1964 to December 31, 1984. Final report

International Nuclear Information System (INIS)

Laughlin, J.S.; Zeitz, L.

1986-01-01

The goal was to develop systems for the determination of absorbed dose in biological research and clinical applications. The primary method under study is the local absorbed dose calorimeter. In addition, secondary dosimetric systems such as ionization chambers, chemical dosimeters and thermoluminescent dosimeters (TLD) are being developed and applied to provide an absolute basis for the evaluation and comparison of experiments, treatments and other procedures using radiation. In keeping with these objectives this project has accomplished significant advances in the following areas: (1) local absorbed dose calorimetry; (2) neutron dosimetry; (3) dosimetry of ultra-high intensity radiation sources; (4) solid state detector and germanium gamma camera program; (5) dosimetry for brachytherapy; and (6) ''non-isolated sensor'' calorimeters

Innovation and the future of advanced dosimetry: 2D to 5D

Science.gov (United States)

Oldham, Mark

2017-05-01

Recent years have witnessed a remarkable evolution in the techniques, capabilities and applications of 3D dosimetry. Initially the goal was simple: to innovate new techniques capable of comprehensively measuring and verifying exquisitely intricate dose distributions from a paradigm changing emerging new therapy, IMRT. Basic questions emerged: how well were treatment planning systems modelling the complex delivery, and how could treatments be verified for safe use on patients? Since that time, equally significant leaps of innovation have continued in the technology of treatment delivery. In addition, clinical practice has been transformed by the addition of on-board imaging capabilities, which tend to hypo-fractionation strategies and margin reduction. The net result is a high stakes treatment setting where the clinical morbidity of any unintended treatment deviation is exacerbated by the combination of highly conformal dose distributions given with reduced margins with fractionation regimens unfriendly to healthy tissue. Not surprisingly this scenario is replete with challenges and opportunities for new and improved dosimetry systems. In particular tremendous interest exists in comprehensive 3D dosimetry systems, and systems that can resolve the dose in moving structures (4D) and even in deforming structures (5D). Despite significant progress in the capability of multi-dimensional dosimetry systems, it is striking that true 3D dosimetry systems are today largely found in academic institutions or specialist clinics. The reasons will be explored. We will highlight innovations occurring both in treatment delivery and in advanced dosimetry methods designed to verify them, and explore current and future opportunities for advanced dosimetry tools in clinical practice and translational research.

Internal dosimetry hazard and risk assessments: methods and applications

International Nuclear Information System (INIS)

Roberts, G.A.

2006-01-01

Routine internal dose exposures are typically (in the UK nuclear industry) less than external dose exposures: however, the costs of internal dosimetry monitoring programmes can be significantly greater than those for external dosimetry. For this reason decisions on when to apply routine monitoring programmes, and the nature of these programmes, can be more critical than for external dosimetry programmes. This paper describes various methods for performing hazard and risk assessments which are being developed by RWE NUKEM Limited Approved Dosimetry Services to provide an indication when routine internal dosimetry monitoring should be considered. (author)

Uncertainty analysis in the determination of absorbed dose in water by Fricke chemical dosimetry

International Nuclear Information System (INIS)

Vasconcelos, Fabia; Aguirre, Eder Aguirre

2016-01-01

This work studies the calculations of uncertainties and the level of confidence that involves the process for obtaining the dose absorbed in water using the method of Fricke dosimetry, developed at Laboratorio de Ciencias Radiologicas (LCR). Measurements of absorbance of samples Fricke, irradiated and non-irradiated is going to use in order to calculate the respective sensitivity coefficients, along with the expressions of the calculation of Fricke dose and the absorbed dose in water. Those expressions are used for calculating the others sensitivity coefficients from the input variable. It is going to use the combined uncertainty and the expanded uncertainty, with a level of confidence of 95.45%, in order to report the uncertainties of the measurement. (author)

Dosimetry applied to radiology and radiotherapy

International Nuclear Information System (INIS)

Yoshimura, Elisabeth Mateus

2010-01-01

Full text. The uses of ionizing radiation in medicine are increasing worldwide, and the population doses increase as well. The actual radiation protection philosophy is based on the balance of risks and benefits related to the practices, and patient dosimetry has an important role in the implementation of this point of view. In radiology the goal is to obtain an image with diagnostic quality with the minimum patient dose. In modern Radiotherapy the cure indexes are higher, giving rise to longer survival times to the patients. Dosimetry in radiotherapy helps the treatment planning systems to get a better protection to critical organs, with higher doses to the tumor, with a guarantee of better life quality to the patient. We will talk about the new trends in dosimetry of medical procedures, including experimental techniques and calculation tools developed to increase reliability and precision of dose determination. In radiology the main concerns of dosimetry are: the transition from film- radiography to digital image, the pediatric patient doses, and the choice of dosimetric quantities to quantify fluoroscopy and tomography patient doses. As far as Radiotherapy is concerned, there is a search for good experimental techniques to quantify doses to tissues adjacent to the target volumes in patients treated with new radiotherapy techniques, as IMRT and heavy particle therapy. (author)

Individual dosimetry of workers and patients: implementation and perspectives; La dosimetrie individuelle des travailleurs et de patients: mise en oeuvre et perspectives

Energy Technology Data Exchange (ETDEWEB)

Rannou, A.; Aubert, B.; Lahaye, Th.; Scaff, P.; Casanova, Ph.; Van Bladel, L.; Queinnec, F.; Valendru, N.; Jehanno, J.; Grude, E.; Berard, Ph.; Desbree, A.; Kafrouni, H.; Paquet, F.; Vanhavere, F.; Bridier, A.; Ginestet, Ch.; Magne, S.; Donadille, L.; Bordy, J.M.; Bottollier-Depois, J.F.; Barrere, J.L.; Ferragut, A.; Metivier, H.; Gaillard-Lecanu, E

2008-07-01

These days organised by the section of the technical protection of the S.F.R.P. review the different techniques of dosimetry used in France and Europe, and present the future orientations.The different interventions are as follow: Individual exposures of the workers: historic assessment and perspectives; medical exposure: where are the doses; legal obligations in individual dosimetry: which are the objective and the need on the subject; the dosimetry follow-up of workers by the S.I.S.E.R.I. system: assessment and perspectives; impact of the norm ISO 20553 on the follow-up of internal exposure; the implementation of the patient dose measurement in Belgium; techniques of passive dosimetry used in Europe; Supervision radiation protection at EDF: long term and short term approach; Comparison active and passive dosimetry at Melox; methodology for the choice of new neutron dosemeters; the working group M.E.D.O.R.: guide of internal dosimetry for the use of practitioners; O.E.D.I.P.E.: tool of modeling for the personalized internal dosimetry; the use of the Monte-Carlo method for the planning of the cancer treatment by radiotherapy becomes a reality; the works of the committee 2 of the ICRP; passive dosimetry versus operational dosimetry: situation in Europe; Implementation of the in vivo dosimetry in a radiotherapy department: experience of the Gustave Roussy institute; experience feedback on the in vivo measures in radiotherapy, based on the use of O.S.L. pellets; multi points O.S.L. instrumentation for the radiation dose monitoring in radiotherapy; dosimetry for extremities for medical applications: principle results of the European contract C.O.N.R.A.D.; references and perspectives in dosimetry; what perspectives for numerical dosimetry, an example: Sievert; system of dose management: how to answer to needs; the last technical evolutions in terms of electronic dosimetry in nuclear power plant; the fourth generation type reactors: what dosimetry. (N.C.)

Ionizing radiations dosimetry: new results in the megagray range

International Nuclear Information System (INIS)

Balian, P.

1989-01-01

Industrial irradiation for food preservation, medical sterilization and plastic processing is in great expansion and an accurate dosimetry in the megagray range is required. It is also required for safety purposes around nuclear reactors or waste storage sites. The study of photon-matter interaction leads us to consider high-dose dosimeters among the solids in which radiolysis occurs. Organic conductors are indeed good candidates for high-dose dosimetry. These materials show original properties due to the great anisotropy of their electronic system. Radiation effects, especially on the resistivity and on the (E.S.R.) Electron Spin Resonance linewidth, are very important. We show that a simple resistance measurement allows an accurate monitoring of the absorbed dose, in the range 0.01 - 50 MGy, for X-rays, gamma-rays and electron irradiations. The E.S.R. linewidth measurements permits the use of small dosimeters between 1 and 100 MGy. Finally, some organic conductors are proposed as high-temperature dosimeters for irradiation performed up to 120 0 C. The irradiated pure silica contains a large variety of defects. Only the E' center seems helpful for dosimetry purposes, and its electron spin resonance (E.S.R.) signal is simply related to the absorbed dose in the range 0.1 - 3 MGy or even, 0.5 kGy - 5 MGy [fr

A multicentre ‘end to end’ dosimetry audit for cervix HDR brachytherapy treatment

International Nuclear Information System (INIS)

Palmer, Antony L.; Diez, Patricia; Gandon, Laura; Wynn-Jones, Andrea; Bownes, Peter; Lee, Chris; Aird, Edwin; Bidmead, Margaret; Lowe, Gerry; Bradley, David; Nisbet, Andrew

2015-01-01

Purpose: To undertake the first multicentre fully ‘end to end’ dosimetry audit for HDR cervix brachytherapy, comparing planned and delivered dose distributions around clinical treatment applicators, with review of local procedures. Materials and methods: A film-dosimetry audit was performed at 46 centres, including imaging, applicator reconstruction, treatment planning and delivery. Film dose maps were calculated using triple-channel dosimetry and compared to RTDose data from treatment planning systems. Deviations between plan and measurement were quantified at prescription Point A and using gamma analysis. Local procedures were also discussed. Results: The mean difference between planned and measured dose at Point A was −0.6% for plastic applicators and −3.0% for metal applicators, at standard uncertainty 3.0% (k = 1). Isodose distributions agreed within 1 mm over a dose range 2–16 Gy. Mean gamma passing rates exceeded 97% for plastic and metal applicators at 3% (local) 2 mm criteria. Two errors were found: one dose normalisation error and one applicator library misaligned with the imaged applicator. Suggestions for quality improvement were also made. Conclusions: The concept of ‘end to end’ dosimetry audit for HDR brachytherapy has been successfully implemented in a multicentre environment, providing evidence that a high level of accuracy in brachytherapy dosimetry can be achieved

GafChromic EBT film dosimetry with flatbed CCD scanner: A novel background correction method and full dose uncertainty analysis

International Nuclear Information System (INIS)

Saur, Sigrun; Frengen, Jomar

2008-01-01

Film dosimetry using radiochromic EBT film in combination with a flatbed charge coupled device scanner is a useful method both for two-dimensional verification of intensity-modulated radiation treatment plans and for general quality assurance of treatment planning systems and linear accelerators. Unfortunately, the response over the scanner area is nonuniform, and when not corrected for, this results in a systematic error in the measured dose which is both dose and position dependent. In this study a novel method for background correction is presented. The method is based on the subtraction of a correction matrix, a matrix that is based on scans of films that are irradiated to nine dose levels in the range 0.08-2.93 Gy. Because the response of the film is dependent on the film's orientation with respect to the scanner, correction matrices for both landscape oriented and portrait oriented scans were made. In addition to the background correction method, a full dose uncertainty analysis of the film dosimetry procedure was performed. This analysis takes into account the fit uncertainty of the calibration curve, the variation in response for different film sheets, the nonuniformity after background correction, and the noise in the scanned films. The film analysis was performed for film pieces of size 16x16 cm, all with the same lot number, and all irradiations were done perpendicular onto the films. The results show that the 2-sigma dose uncertainty at 2 Gy is about 5% and 3.5% for landscape and portrait scans, respectively. The uncertainty gradually increases as the dose decreases, but at 1 Gy the 2-sigma dose uncertainty is still as good as 6% and 4% for landscape and portrait scans, respectively. The study shows that film dosimetry using GafChromic EBT film, an Epson Expression 1680 Professional scanner and a dedicated background correction technique gives precise and accurate results. For the purpose of dosimetric verification, the calculated dose distribution can

GafChromic EBT film dosimetry with flatbed CCD scanner: a novel background correction method and full dose uncertainty analysis.

Science.gov (United States)

Saur, Sigrun; Frengen, Jomar

2008-07-01

Film dosimetry using radiochromic EBT film in combination with a flatbed charge coupled device scanner is a useful method both for two-dimensional verification of intensity-modulated radiation treatment plans and for general quality assurance of treatment planning systems and linear accelerators. Unfortunately, the response over the scanner area is nonuniform, and when not corrected for, this results in a systematic error in the measured dose which is both dose and position dependent. In this study a novel method for background correction is presented. The method is based on the subtraction of a correction matrix, a matrix that is based on scans of films that are irradiated to nine dose levels in the range 0.08-2.93 Gy. Because the response of the film is dependent on the film's orientation with respect to the scanner, correction matrices for both landscape oriented and portrait oriented scans were made. In addition to the background correction method, a full dose uncertainty analysis of the film dosimetry procedure was performed. This analysis takes into account the fit uncertainty of the calibration curve, the variation in response for different film sheets, the nonuniformity after background correction, and the noise in the scanned films. The film analysis was performed for film pieces of size 16 x 16 cm, all with the same lot number, and all irradiations were done perpendicular onto the films. The results show that the 2-sigma dose uncertainty at 2 Gy is about 5% and 3.5% for landscape and portrait scans, respectively. The uncertainty gradually increases as the dose decreases, but at 1 Gy the 2-sigma dose uncertainty is still as good as 6% and 4% for landscape and portrait scans, respectively. The study shows that film dosimetry using GafChromic EBT film, an Epson Expression 1680 Professional scanner and a dedicated background correction technique gives precise and accurate results. For the purpose of dosimetric verification, the calculated dose distribution

Liquid scintillator for 2D dosimetry for high-energy photon beams

International Nuclear Information System (INIS)

Poenisch, Falk; Archambault, Louis; Briere, Tina Marie; Sahoo, Narayan; Mohan, Radhe; Beddar, Sam; Gillin, Michael T.

2009-01-01

Complex radiation therapy techniques require dosimetric verification of treatment planning and delivery. The authors investigated a liquid scintillator (LS) system for application for real-time high-energy photon beam dosimetry. The system was comprised of a transparent acrylic tank filled with liquid scintillating material, an opaque outer tank, and a CCD camera. A series of images was acquired when the tank with liquid scintillator was irradiated with a 6 MV photon beam, and the light data measured with the CCD camera were filtered to correct for scattering of the optical light inside the liquid scintillator. Depth-dose and lateral profiles as well as two-dimensional (2D) dose distributions were found to agree with results from the treatment planning system. Further, the corrected light output was found to be linear with dose, dose rate independent, and is robust for single or multiple acquisitions. The short time needed for image acquisition and processing could make this system ideal for fast verification of the beam characteristics of the treatment machine. This new detector system shows a potential usefulness of the LS for 2D QA.

Liquid scintillator for 2D dosimetry for high-energy photon beams

Energy Technology Data Exchange (ETDEWEB)

Poenisch, Falk; Archambault, Louis; Briere, Tina Marie; Sahoo, Narayan; Mohan, Radhe; Beddar, Sam; Gillin, Michael T. [Department of Radiation Physics, University of Texas M. D. Anderson Cancer Center, 1515 Holcombe Boulevard., Unit 94, Houston, Texas 77030 (United States)

2009-05-15

Complex radiation therapy techniques require dosimetric verification of treatment planning and delivery. The authors investigated a liquid scintillator (LS) system for application for real-time high-energy photon beam dosimetry. The system was comprised of a transparent acrylic tank filled with liquid scintillating material, an opaque outer tank, and a CCD camera. A series of images was acquired when the tank with liquid scintillator was irradiated with a 6 MV photon beam, and the light data measured with the CCD camera were filtered to correct for scattering of the optical light inside the liquid scintillator. Depth-dose and lateral profiles as well as two-dimensional (2D) dose distributions were found to agree with results from the treatment planning system. Further, the corrected light output was found to be linear with dose, dose rate independent, and is robust for single or multiple acquisitions. The short time needed for image acquisition and processing could make this system ideal for fast verification of the beam characteristics of the treatment machine. This new detector system shows a potential usefulness of the LS for 2D QA.

MO-B-BRB-02: 3D Dosimetry in the Clinic: IMRT Technique Validation in Sweden