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Sample records for tps radiotherapy dosimetry

  1. External audit in radiotherapy dosimetry

    International Nuclear Information System (INIS)

    Thwaites, D.I.; Western General Hospital, Edinburgh

    1996-01-01

    Quality audit forms an essential part of any comprehensive quality assurance programme. This is true in radiotherapy generally and in specific areas such as radiotherapy dosimetry. Quality audit can independently test the effectiveness of the quality system and in so doing can identify problem areas and minimize their possible consequences. Some general points concerning quality audit applied to radiotherapy are followed by specific discussion of its practical role in radiotherapy dosimetry, following its evolution from dosimetric intercomparison exercises to routine measurement-based on-going audit in the various developing audit networks both in the UK and internationally. Specific examples of methods and results are given from some of these, including the Scottish+ audit group. Quality audit in radiotherapy dosimetry is now well proven and participation by individual centres is strongly recommended. Similar audit approaches are to be encouraged in other areas of the radiotherapy process. (author)

  2. 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

  3. Radiotherapy gel dosimetry: a review

    International Nuclear Information System (INIS)

    Baldock, C.

    2003-01-01

    Radiation therapy or radiotherapy is a common form of cancer treatment. Recent advances in radiotherapy such as intensity modulated radiation therapy indicate that treatment outcomes may be improved. The principle limitation of these more advanced techniques of radiation therapy is the ability to quantify the absorbed radiation dose to the tumour which is related to the 3- dimensional geometry of the tumour. The main advances in 3-dimensional radiation dosimetry are the development of radiation sensitive polymer gel dosimeters. The use of radiation sensitive gels for radiation dosimetry in cancer therapy was first suggested in the 1950s. It was subsequently shown in 1984 that radiation induced changes in nuclear magnetic resonance relaxation properties of gels infused with conventional Fricke dosimetry solutions could be measured. Due to diffusion-related limitations in the use of Fricke gels, alternative polymer gel dosimeters were subsequently suggested in 1992. Since then, both magnetic resonance and optical imaging techniques have been used to evaluate polymer gel dosimeters to produce three-dimensional radiation dose distributions. More recently the uses of x-ray computer tomography and vibrational spectroscopy have also been demonstrated as valuable techniques in the evaluation of these dosimetry gels. Although not yet used routinely clinically, applications of these radiologically soft-tissue equivalent gel dosimeters have been shown to have great potential in the evaluation of complex radiation dose distributions. A review of 3-dimensional radiotherapy gel dosimetry is presented

  4. Dosimetry in radiotherapy. V.1

    International Nuclear Information System (INIS)

    1988-01-01

    A series of symposia on dosimetry in medicine and biology have been held by the IAEA in co-operation with WHO. The present symposium was the first one focusing on ''Dosimetry in Radiotherapy''. The papers presented reflected the different steps in the calibration chain such as the calibration standards established by the National Standards Laboratories and the conversion of the reading of calibrated instruments to the desired quantity, i.e. absorbed dose to water at a reference point in the user's beam at the radiotherapy clinic. The programme further examined the procedures necessary for optimization of the treatment of the patient, such as treatment planning methods, dose distribution studies, new techniques of dose measurement, improvements in the physical dose distributions/conformation therapy and special problems involved in total body treatments. Results of quality assurance in radiotherapy were presented from local hospitals as well as from national and international studies. Refs, figs and tabs

  5. Dosimetry in radiotherapy. V.2

    International Nuclear Information System (INIS)

    1988-01-01

    A series of symposia on dosimetry in medicine and biology have been held by the IAEA in co-operation with WHO. The present symposium was the first one focusing on ''Dosimetry in Radiotherapy''. The papers presented reflected the different steps in the calibration chain such as the calibration standards established by the National Standards Laboratories and the conversion of the reading of calibrated instruments to the desired quantity, i.e. absorbed dose to water at a reference point in the user's beam at the radiotherapy clinic. The programme further examined the procedures necessary for optimization of the treatment of the patient, such as treatment planning methods, dose distribution studies, new techniques of dose measurement, improvements in the physical dose distributions/conformation therapy and special problems involved in total body treatments. Results of quality assurance in radiotherapy were presented from local hospitals as well as from national and international studies. Refs, figs and tabs

  6. Dosimetry audit simulation of treatment planning system in multicenters radiotherapy

    Science.gov (United States)

    Kasmuri, S.; Pawiro, S. A.

    2017-07-01

    Treatment Planning System (TPS) is an important modality that determines radiotherapy outcome. TPS requires input data obtained through commissioning and the potentially error occurred. Error in this stage may result in the systematic error. The aim of this study to verify the TPS dosimetry to know deviation range between calculated and measurement dose. This study used CIRS phantom 002LFC representing the human thorax and simulated all external beam radiotherapy stages. The phantom was scanned using CT Scanner and planned 8 test cases that were similar to those in clinical practice situation were made, tested in four radiotherapy centers. Dose measurement using 0.6 cc ionization chamber. The results of this study showed that generally, deviation of all test cases in four centers was within agreement criteria with average deviation about -0.17±1.59 %, -1.64±1.92 %, 0.34±1.34 % and 0.13±1.81 %. The conclusion of this study was all TPS involved in this study showed good performance. The superposition algorithm showed rather poor performance than either analytic anisotropic algorithm (AAA) and convolution algorithm with average deviation about -1.64±1.92 %, -0.17±1.59 % and -0.27±1.51 % respectively.

  7. Film dosimetry in conformal radiotherapy

    Energy Technology Data Exchange (ETDEWEB)

    Danciu, C.; Proimos, B.S. [Patras Univ. (Greece). Dept. of Medical Physics

    1995-12-01

    Dosimetry, through a film sandwiched in a transverse cross-section of a solid phantom, is a method of choice in Conformal Radiotherapy because: (a) the blackness (density) of the film at each point offers a measure of the total dose received at that point, and (b) the film is easily calibrated by exposing a film strip in the same cross-section, through a stationary field. The film must therefore have the following properties: (a) it must be slow, in order not to be overexposed, even at a therapeutic dose of 200 cGy, and (b) the response of the film (density versus dose curve) must be independent of the photon energy spectrum. A few slow films were compared. It was found that the Kodak X-Omat V for therapy verification was the best choice. To investigate whether the film response was independent of the photon energy, response curves for six depths, starting from the depth of maximum dose to the depth of 25 cm, in solid phantom were derived. The vertical beam was perpendicular to the anterior surface of the phantom, which was at the distance of 100 cm from the source and the field was 15x15 cm at that distance. This procedure was repeated for photon beams emitted by a Cobalt-60 unit, two 6 MV and 15 MV Linear Accelerators, as well as a 45 MV Betatron. For each of those four different beams the film response was the same for all six depths. The results, as shown in the diagrams, are very satisfactory. The response curve under a geometry similar to that actually applied, when the film is irradiated in a transverse cross-section of the phantom, was derived. The horizontal beam was almost parallel (angle of 85) to the plane of the film. The same was repeated with the central ray parallel to the film (angle 90) and at a distance of 1.5 cm from the horizontal film. The field size was again 15x15 at the lateral entrance surface of the beam. The response curves remained the same, as when the beam was perpendicular to the films.

  8. 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)

  9. Dosimetry audit of radiotherapy treatment planning systems.

    Science.gov (United States)

    Bulski, Wojciech; Chełmiński, Krzysztof; Rostkowska, Joanna

    2015-07-01

    In radiotherapy Treatment Planning Systems (TPS) various calculation algorithms are used. The accuracy of dose calculations has to be verified. Numerous phantom types, detectors and measurement methodologies are proposed to verify the TPS calculations with dosimetric measurements. A heterogeneous slab phantom has been designed within a Coordinated Research Project (CRP) of the IAEA. The heterogeneous phantom was developed in the frame of the IAEA CRP. The phantom consists of frame slabs made with polystyrene and exchangeable inhomogeneity slabs equivalent to bone or lung tissue. Special inserts allow to position thermoluminescent dosimeters (TLD) capsules within the polystyrene slabs below the bone or lung equivalent slabs and also within the lung equivalent material. Additionally, there are inserts that allow to position films or ionisation chamber in the phantom. Ten Polish radiotherapy centres (of 30 in total) were audited during on-site visits. Six different TPSs and five calculation algorithms were examined in the presence of inhomogeneities. Generally, most of the results from TLD were within 5 % tolerance. Differences between doses calculated by TPSs and measured with TLD did not exceed 4 % for bone and polystyrene equivalent materials. Under the lung equivalent material, on the beam axis the differences were lower than 5 %, whereas inside the lung equivalent material, off the beam axis, in some cases they were of around 7 %. The TLD results were confirmed with the ionisation chamber measurements. The comparison results of the calculations and the measurements allow to detect limitations of TPS calculation algorithms. The audits performed with the use of heterogeneous phantom and TLD seem to be an effective tool for detecting the limitations in the TPS performance or beam configuration errors at audited radiotherapy departments. © The Author 2015. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  10. Worldwide QA networks for radiotherapy dosimetry

    International Nuclear Information System (INIS)

    Izewska, J.; Svensson, H.; Ibbott, G.

    2002-01-01

    A number of national or international organizations have developed various types and levels of external audits for radiotherapy dosimetry. There are three major programmes who make available external audits, based on mailed TLD (thermoluminescent dosimetry), to local radiotherapy centres on a regular basis. These are the IAEA/WHO TLD postal dose audit service operating worldwide, the European Society for Therapeutic Radiology and Oncology (ESTRO) system, EQUAL, in European Union (EU) and the Radiological Physics Center (RPC) in North America. The IAEA, in collaboration with WHO, was the first organization to initiate TLD audits on an international scale in 1969, using mailed system, and has a well-established programme for providing dose verification in reference conditions. Over 32 years, the IAEA/WHO TLD audit service has checked the calibration of more than 4300 radiotherapy beams in about 1200 hospitals world-wide. Only 74% of those hospitals who receive TLDs for the first time have results with deviation between measured and stated dose within acceptance limits of ±5%, while approximately 88% of the users that have benefited from a previous TLD audit are successful. EQUAL, an audit programme set up in 1998 by ESTRO, involves the verification of output for high energy photon and electron beams, and the audit of beam parameters in non-reference conditions. More than 300 beams are checked each year, mainly in the countries of EU, covering approximately 500 hospitals. The results show that although 98% of the beam calibrations are within the tolerance level of ±5%, a second check was required in 10% of the participating centres, because a deviation larger than ±5% was observed in at least one of the beam parameters in non-reference conditions. EQUAL has been linked to another European network (EC network) which tested the audit methodology prior to its application. The RPC has been funded continuously since 1968 to monitor radiation therapy dose delivery at

  11. 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

  12. 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

  13. TRS 398 dosimetry protocol for radiotherapy

    International Nuclear Information System (INIS)

    Palmans, H.; Smyth, V.

    2004-01-01

    Full text: In recent years, international codes of practice based on absorbed dose to water standards have been published for the clinical reference dosimetry of external beams. It has become widely accepted that dosimetry of radiotherapeutic beams should be based on these standards. These codes of practice are a major improvement over earlier ones that used air kerma calibration factors as they are based on a calibration directly in a phantom in terms of the quantity of interest. The previous codes begin with calibration in air in terms of air kerma, then use theoretical and generic conversion factors to obtain dose to water that do not take account of chamber-to-chamber variation. Other good reasons for implementing the new codes are that they are conceptually simpler, include improved physical data and improve the consistency for various ionisation chamber types as well as between different beam types. TRS-3982,3 is a new Code of Practice (CoP) for reference dosimetry of external radiotherapy beams based on absorbed dose to, water calibrations and was published by the IAEA in a joint effort with the WHO, PAHO and ESTRO. It is the first CoP of its kind comprehensively covering all external radiotherapy beams except neutrons. The Radiotherapy Interest Group (RJG) of the ACPSEM has recommended that radiotherapy centres in Australia and New Zealand implement this CoP by the end of 2004. In this workshop, the general philosophy of the CoP will be outlined which will provide a framework for each of the individual subcodes. Although it represents just one of the potential implementations of the CoP, this workshop will deal only with dosimetry based on a cylindrical ionisation chamber with an absorbed dose calibration factor in 60Co from the standards laboratory. With the framework of the code in mind, it is straightforward to identify the basic steps that are required for measuring absorbed dose under reference conditions in a high-energy photon beam. The same is true

  14. An IAEA Survey of Dosimetry Audit Networks for Radiotherapy

    International Nuclear Information System (INIS)

    Grochowska, Paulina; Izewska, Joanna

    2013-01-01

    A Survey: In 2010, the IAEA undertook a task to investigate and review the coverage and operations of national and international dosimetry audit programmes for radiotherapy. The aim was to organize the global database describing the activities of dosimetry audit networks in radiotherapy. A dosimetry audit questionnaire has been designed at an IAEA consultants' meeting held in 2010 for organizations conducting various levels of dosimetry audits for radiotherapy. Using this questionnaire, a survey was conducted for the first time in 2010 and repeated in 2011. Request for information on different aspects of the dosimetry audit was included, such as the audit framework and resources, its coverage and scope, the dosimetry system used and the modes of audit operation, i.e. remotely and through on-site visits. The IAEA questionnaire was sent to over 80 organizations, members of the IAEA/WHO Network of Secondary Standards Dosimetry Laboratories (SSDLs) and other organizations known for having operated dosimetry audits for radiotherapy in their countries or internationally. Survey results and discussion: In response to the IAEA survey, 53 organizations in 45 countries confirmed that they operate dosimetry audit services for radiotherapy. Mostly, audits are conducted nationally, however there are five organizations offering audits abroad, with two of them operating in various parts of the world and three of them at the regional level, auditing radiotherapy centres in neighbouring countries. The distribution of dosimetry audit services in the world is given. (author)

  15. Radiation dosimetry in radiotherapy with internal emitters

    International Nuclear Information System (INIS)

    Stabin, Michael G.

    1997-01-01

    Full text. Radiation dosimetry radionuclides are currently being labeled to various biological agents used in internal emitter radiotherapy. This talk will review the various technologies and types of radiolabel in current use, with focus on the characterization of the radiation dose to the various important tissues of the body. Methods for obtaining data, developing kinetic models, and calculating radiation doses will be reviewed. Monoclonal antibodies are currently being labeled with both alpha and beta emitting radionuclides in attempts to find effective agents against cancer. Several radionuclides are also being used as bone pain palliation agents. These agents must be studied in clinical trials to determine the biokinetics and radiation dosimetry prior to approval for general use. In such studies, it is important to ensure the collection of the appropriate kinds of data and to collect the data at appropriate time intervals. The uptake and retention of activity in all significant source organs and in excreta be measured periodically (with at least 2 data points phase of uptake or clearance). Then, correct dosimetry methods must be applied - the best available methods for characterizing the radionuclide kinetic and for estimating the dosimetry in the various organs of the body especially the marrow, should be used. Attempts are also under way to develop methods for estimating true patient-specific dosimetry. Cellular and animal studies are also. Valuable in evaluating the efficacy of the agents in shrinking or eliminating tumors; some results from such studies will also be discussed. The estimation of radiation doses to patients in therapy with internal emitters involves several complex phases of analysis. Careful attention to detail and the use of the best available methods are essential to the protection of the patient and a successful outcome

  16. Dosimetry on the radiological risks prevention in radiotherapy

    International Nuclear Information System (INIS)

    Fornet R, O. M.; Perez G, F.

    2014-08-01

    Dosimetry in its various forms plays a determining role on the radiological risks prevention in radiotherapy. To prove this in this paper is shown an analysis based on the risk matrix method, how the dosimetry can influence in each stages of a radiotherapy service; installation and acceptance, operation, maintenance and calibration. For each one of these stages the role that can play is analyzed as either the initiating event of a radiological accident or limiting barrier of these events of the dosimetric processes used for the individual dosimetry, the area monitoring, fixed or portable, for radiation beam dosimetry and of the patients for a radiotherapy service with cobalt-therapy equipment. The result of the study shows that the application of a prospective approach in the role evaluation of dosimetry in the prevention and mitigation of the consequences of a radiological accident in radiotherapy is crucial and should be subject to permanent evaluation at each development stage of these services. (author)

  17. The UK radiotherapy dosimetry audit network

    International Nuclear Information System (INIS)

    Thwaites, D.I.

    2002-01-01

    Full text: Radiotherapy dosimetry intercomparison in the UK has been carried out in limited studies since the 1960s. However the first national dosimetry intercomparison involving all radiotherapy centres was conducted in the late 1980s. This was based on visits to each centre, using ionisation chamber dosimetry. It audited megavoltage photon beam calibration and other single field parameters. It also measured doses in a three-field 'treatment' in a trapezoidal phantom constructed from epoxy-resin water-equivalent material and compared these to locally planned doses. This included off-axis points, oblique incidence, inhomogeneities, etc. The study found mean measured beam calibration doses close to stated values (ratio 1.003), with a standard deviation (sd) of the distribution of 1.5% and 97% of doses within the pro-set 3% tolerance. For the planned multi-field irradiations, mean dose ratios (measured/stated) were 1.01 (sd 3%, 90% of results within 5%). A number of discrepancies were identified, leading to improved practice. A follow up study (mid-1990s) for electron beam audit also repeated the megavoltage photon calibration audit. For photons, an improvement was noted (mean ratio 1.003, sd 1.0%, 100% within 3%), whilst for electron beams, the mean ratio of measured/stated dose was 0.994 (sd 1.8%, 94% within 3%, 99% within 5%). In parallel with - and growing out of - this, a national audit network began to develop in 1991/2. It utilised similar methodology to the intercomparison and a network approach to allow parallel developments of the scope of the system. The network has eight regional groups, each with up to 10 radiotherapy centres, serving average populations of 7-8 million. Each group organises audits of its own centres and has developed at its own pace. Most have piloted methodology, phantoms, etc. for new audits which can then be used by other groups. All 65 UK centres are included. The network is co-ordinated by an IPEM Steering Committee (current chair

  18. Radiological response and dosimetry in physical phantom of head and neck for 3D conformational radiotherapy

    International Nuclear Information System (INIS)

    Thompson, Larissa

    2013-01-01

    Phantoms are tools for simulation of organs and tissues of the human body in radiology and radiotherapy. This thesis describes the development, validation and, most importantly, the use of a physical head and neck phantom in radiology and radiotherapy, with the purpose of evaluating dose distribution using Gafchromic EBT2 film in 15 MV 3D conformal radiotherapy. The work was divided in two stages, (1) development of new equivalent tissues and improvement of the physical phantom, and (2) use of the physical phantom in experimental dosimetry studies. In phase (1) parameters such as mass density, chemical composition of tissues, anatomical and biometric measurements were considered, as well as aspects of imaging by computed tomography (CT) and radiological response representation in Hounsfield Units (HU), which were compared with human data. Radiological experiments of in-phantom simulated brain pathologies were also conducted. All those results matched human-sourced data, therefore the physical phantom is a suitable simulator that may be used to enhance radiological protocols and education in medical imaging. The main objective in phase (2) was to evaluate the spatial dose distribution in a brain tumor simulator inserted inside the head and neck phantom developed by the Ionizing Radiation Research Group (NRI), exposed to 15 MV 3D conformal radiotherapy, for internal dose assessment. Radiation planning was based on CT images of the physical phantom with a brain tumor simulator made with equivalent material. The treatment planning system (TPS), CAT3D software, used CT images and prescribed a dose of 200 cGy, distributed in three fields of radiation, in a T-shaped pattern. The TPS covered the planning treatment volume (PTV) with 97% of the prescribed dose. A solid water phantom and radiochromic Gafchromic EBT2 film were used for calibration procedures, generating a dose response curve as a function of optical density (OD). After calibration and irradiation, the film

  19. Alanine-ESR dosimetry for radiotherapy IAEA experience

    International Nuclear Information System (INIS)

    Mehta, K.; Girzikowsky, R.; )

    1997-01-01

    At present, the most commonly used transfer dosimeters for radiotherapy applications are TL dosemeters. They are being used for intercomparison between SSDLs (about 70) and the IAEA dosimetry laboratory. However, there are some undesirable characteristics of this dosimetry system. We have a study in progress at the IAEA to evaluate the alanine-ESR systems as an alternative to TLDs. There are several desirable qualities which make alanine an attractive dosemeter. Preliminary data suggest that the alanine-ESR dosimetry system has the potential to replace TLDs for intercomparison amongst SSDLs in the therapy-level dose regions. (Author)

  20. On the clinical applicability of large-area 2-D TL dosimetry for verifying small photon radiotherapy beams

    Energy Technology Data Exchange (ETDEWEB)

    Kabat, D.; Nahajowski, D.; Gora, E.; Rozwadowska-Bogusz, B.; Lesiak, J.; Polak, B. [Centre of Oncology, Maria Sklodowska-Curie Memorial Institute, Krakow Branch, Garncarska 11, 31-115 Krakow (Poland); Czopyk, L.; Olko, P. [Institute of Nuclear Physics, Polish Academy of Sciences (IFJ PAN), Krakow (Poland); Waligorski, M.P.R. [Centre of Oncology, Maria Sklodowska-Curie Memorial Institute, Krakow Branch, Garncarska 11, 31-115 Krakow (Poland); Institute of Nuclear Physics, Polish Academy of Sciences (IFJ PAN), Krakow (Poland)], E-mail: z5waligo@cyf-kr.edu.pl

    2008-02-15

    A two-dimensional (2-D) thermoluminescence (TL) dosimetry system consisting of LiF:Mg,Cu,P (MCP-N)-ETFE (Teflon)-based TL foils and a large-area TLD reader equipped with a CCD camera, has been developed at the Institute of Nuclear Physics (IFJ PAN). At our radiotherapy department we tested the applicability of this system to verify 2-D dose distributions in a multileaf collimator-shaped 6 MV radiotherapy beam of size about 3x3cm{sup 2}. Water-immersible TL foils, of size 50x50mm{sup 2}, c. 0.2 mm thickness and density 1.95g/cm{sup 3} were placed in a water phantom and exposed at different depths, across or along the beam axis, read out using a 2-D TL reader equipped with a CCD camera and processed by reader software, yielding respective beam dose profiles in digital matrix form. We were also able to further process these matrices with the software of the therapy planning system (TPS) which we use routinely for clinical purposes. Satisfactory agreement found between dose distributions measured as percent depth dose or transverse beam profiles at different depths and respective distributions calculated by the TPS, confirms that the 2-D TL dosimetry is a promising technique for quality assurance of radiotherapy beams where steep dose gradients may occur over small field areas.

  1. Dosimetry audits and intercomparisons in radiotherapy: A Malaysian profile

    Science.gov (United States)

    M. Noor, Noramaliza; Nisbet, A.; Hussein, M.; Chu S, Sarene; Kadni, T.; Abdullah, N.; Bradley, D. A.

    2017-11-01

    Quality audits and intercomparisons are important in ensuring control of processes in any system of endeavour. Present interest is in control of dosimetry in teletherapy, there being a need to assess the extent to which there is consistent radiation dose delivery to the patient. In this study we review significant factors that impact upon radiotherapy dosimetry, focusing upon the example situation of radiotherapy delivery in Malaysia, examining existing literature in support of such efforts. A number of recommendations are made to provide for increased quality assurance and control. In addition to this study, the first level of intercomparison audit i.e. measuring beam output under reference conditions at eight selected Malaysian radiotherapy centres is checked; use being made of 9 μm core diameter Ge-doped silica fibres (Ge-9 μm). The results of Malaysian Secondary Standard Dosimetry Laboratory (SSDL) participation in the IAEA/WHO TLD postal dose audit services during the period between 2011 and 2015 will also been discussed. In conclusion, following review of the development of dosimetry audits and the conduct of one such exercise in Malaysia, it is apparent that regular periodic radiotherapy audits and intercomparison programmes should be strongly supported and implemented worldwide. The programmes to-date demonstrate these to be a good indicator of errors and of consistency between centres. A total of ei+ght beams have been checked in eight Malaysian radiotherapy centres. One out of the eight beams checked produced an unacceptable deviation; this was found to be due to unfamiliarity with the irradiation procedures. Prior to a repeat measurement, the mean ratio of measured to quoted dose was found to be 0.99 with standard deviation of 3%. Subsequent to the repeat measurement, the mean distribution was 1.00, and the standard deviation was 1.3%.

  2. In vivo dosimetry for lung radiotherapy including SBRT.

    Science.gov (United States)

    McCurdy, Boyd M C; McCowan, Peter M

    2017-12-01

    SBRT for lung cancer is being rapidly adopted as a treatment option in modern radiotherapy centres. This treatment is one of the most complex in common clinical use, requiring significant expertise and resources. It delivers a high dose per fraction (typically ∼6-30Gy/fraction) over few fractions. The complexity and high dose delivered in only a few fractions make powerful arguments for the application of in vivo dosimetry methods for these treatments to enhance patient safety. In vivo dosimetry is a group of techniques with a common objective - to estimate the dose delivered to the patient through a direct measurement of the treatment beam(s). In particular, methods employing an electronic portal imaging device have been intensely investigated over the past two decades. Treatment verification using in vivo dosimetry approaches has been shown to identify errors that would have been missed with other common quality assurance methods. With the addition of in vivo dosimetry to verify treatments, medical physicists and clinicians have a higher degree of confidence that the dose has been delivered to the patient as intended. In this review, the technical aspects and challenges of in vivo dosimetry for lung SBRT will be presented, focusing on transit dosimetry applications using electronic portal imaging devices (EPIDs). Currently available solutions will be discussed and published clinical experiences, which are very limited to date, will be highlighted. Copyright © 2017. Published by Elsevier Ltd.

  3. Methods and computer readable medium for improved radiotherapy dosimetry planning

    Science.gov (United States)

    Wessol, Daniel E.; Frandsen, Michael W.; Wheeler, Floyd J.; Nigg, David W.

    2005-11-15

    Methods and computer readable media are disclosed for ultimately developing a dosimetry plan for a treatment volume irradiated during radiation therapy with a radiation source concentrated internally within a patient or incident from an external beam. The dosimetry plan is available in near "real-time" because of the novel geometric model construction of the treatment volume which in turn allows for rapid calculations to be performed for simulated movements of particles along particle tracks therethrough. The particles are exemplary representations of alpha, beta or gamma emissions emanating from an internal radiation source during various radiotherapies, such as brachytherapy or targeted radionuclide therapy, or they are exemplary representations of high-energy photons, electrons, protons or other ionizing particles incident on the treatment volume from an external source. In a preferred embodiment, a medical image of a treatment volume irradiated during radiotherapy having a plurality of pixels of information is obtained.

  4. Dosimetry intercomparisons between fast neutron radiotherapy facilities

    International Nuclear Information System (INIS)

    Almond, P.R.; Smith, A.R.; Smathers, J.B.; Otte, V.A.

    1975-01-01

    Neutron dosimetry intercomparisons have been made between M.D. Anderson Hospital and Tumor Institute, Naval Research Laboratory, University of Washington Hospital, and Hammersmith Hospital. The parameters that are measured during these visits are: tissue kerma in air, tissue dose at depth of dose maximum, depth dose, beam profiles, neutron/gamma ratios and photon calibrations of ionization chambers. A preliminary report of these intercomparisons will be given including a comparison of the calculation and statement of tumor doses for each institution

  5. External quality audit programmes for radiotherapy dosimetry and equipment

    International Nuclear Information System (INIS)

    Thwaites, D.I.

    1997-01-01

    It is widely accepted that individual radiotherapy centres should have in place a comprehensive quality assurance programme on all the necessary steps for the delivery of safe accurate treatment. As regards the performance of radiotherapy equipment and dosimetry, the most widely used process of external checking has been dosimetry intercomparison, comparing independently measured doses to locally stated doses in a variety of conditions. These have been at a number of different levels: from basic beam calibration; up to and including exercises employing anatomic or pseudo-anatomic phantoms and incorporating tests of treatment planning equipment and procedures. Some of these have been one-off exercises, whilst others are continuing, or have given rise to on-going quality audit programmes on a national (or wider) basis. A number of these have evolved, or are evolving, into audits which include external checking of the achievement of standards in performance of treatment equipment, as well as in the dosimetry in each institution involved. The principles and methodologies of the various types of external checking programmes for treatment equipment and dosimetry are reviewed, covering the experimental approaches and the tolerances applied. What is included in a given programme will, of necessity, depend on the resources available and the purpose of the exercise. Methods and tolerances must be matched to endpoint. Tolerance levels must take into account the experimental uncertainties of the measurement methods employed. Finally, external audit can only be used to complement, and in conjunction with, institutional quality assurance programmes and not as a substitute for them

  6. Synthetic diamond devices for medical dosimetry applied to radiotherapy

    International Nuclear Information System (INIS)

    Descamps, C.

    2007-06-01

    The aim of this thesis, lead in the framework of an integrated European project entitled M.A.E.S.T.R.O. for ' Methods and Advanced Equipment for Simulation and Treatment in Radio Oncology', was to develop and test synthetic diamond detector in clinical environment for new modalities used in radiotherapy. Diamond is a good candidate for the detection of high energy beams in medical fields. It can be used for passive dosimetry, as thermoluminescent dosimeters or for active dosimetry as ionisation chambers. These two applications are presented here. Concerning the thermoluminescence, several impurities or dopants (boron, phosphorus, and nitrogen) have been incorporated in the diamond films during growth, in order to modify the material dosimetric properties and a detailed study of nitrogen-containing films is proposed. The second part presents the results obtained in active dosimetry. Two guide lines were followed: the measurement set-up optimisation and the material modification. The first dosimetric studies under radiotherapy beams concerning nitrogen-containing polycrystalline diamond as well as high purity single crystal diamond are conclusive. The detectors behaviours are in agreement with the recommendations of the International Atomic Energy Agency (IAEA). (author)

  7. Organic scintillators with long luminescent lifetimes for radiotherapy dosimetry

    DEFF Research Database (Denmark)

    Beierholm, Anders Ravnsborg; Lindvold, Lars René; Andersen, Claus Erik

    2011-01-01

    for radiotherapy treatments deliver pulsed beams, the stem signal can be suppressed using dosimeter materials with luminescent lifetimes much longer than that of the stem signal. However, producing organic scintillators with long luminescent lifetimes has proven difficult in practice. We report on the results...... component on the order of 20 μs was estimated for the custom-made organic scintillator, while the commercial scintillator exhibited a fast component of approximately 5 ns lifetime (7 ns as stated by the manufacturer) and an approximate 10 μs lifetime slow component. Although these lifetimes are not long...... enough for practical applications in radiotherapy dosimetry, this study supports that the stem signal can be greatly reduced by applying a temporal gating....

  8. A reusable OSL-film for 2D radiotherapy dosimetry

    Science.gov (United States)

    Wouter, Crijns; Dirk, Vandenbroucke; Paul, Leblans; Tom, Depuydt

    2017-11-01

    Optical stimulated luminescence (OSL) combines reusability, sub-mm resolution, and a linear dose response in a single radiation detection technology. Such a combination is currently lacking in radiotherapy dosimetry. But OSL-films have a strong energy dependent response to keV photons due to a relative high effective atomic number (Z eff). The current work studied the applicability of a 2D OSL-film with a reduced Z eff as (IMRT/VMAT) dosimeter. Based on their commercial OSL-film experience, Agfa Healthcare N.V. produced a new experimental OSL-film for RT dosimetry. This film had a lower effective atomic number compared to the films used in radiology. Typical 2D dosimeter requirements such as uniformity, dose response, signal stability with time, and angular dependence were evaluated. Additionally, the impact of a possible residual energy dependence was assessed for the infield as well as the out-of-field region of both static beams and standard intensity modulated patterns (chair and pyramid). The OSL-film’s reusable nature allowed for a film specific absolute and linear calibration including a flood-field uniformity correction. The OSL-film was scanned with a CR-15X engine based reader using a strict timing (i.e. 4 min after ‘beam on’ or as soon as possible) to account for spontaneous recombination. The OSL-film had good basic response properties: non-uniformities  ⩽2.6%, a linear dose response (0-32 Gy), a linear signal decay (0.5% min-1) over the 20 min measured, and limited angular dependence  ⩽2.6%. Due to variations of the energy spectrum, larger dose differences were noted outside the central region of the homogenous phantom and outside both static and IMRT fields. However, the OSL-film’s measured dose differences of the IMRT patterns were lower than those of Gafchromic EBT measurements ([-1.6%, 2.1%] versus [-2.9%, 3.6%]). The current OSL-film could be used as a reusable high resolution dosimeter with read-out immediately after

  9. Verification of the pure alanine in PMMA tube dosimeter applicability for dosimetry of radiotherapy photon beams: a feasibility study.

    Science.gov (United States)

    Al-Karmi, Anan M; Ayaz, Ali Asghar H; Al-Enezi, Mamdouh S; Abdel-Rahman, Wamied; Dwaikat, Nidal

    2015-09-01

    Alanine dosimeters in the form of pure alanine powder in PMMA plastic tubes were investigated for dosimetry in a clinical application. Electron paramagnetic resonance (EPR) spectroscopy was used to measure absorbed radiation doses by detection of signals from radicals generated in irradiated alanine. The measurements were performed for low-dose ranges typical for single-fraction doses often used in external photon beam radiotherapy. First, the dosimeters were irradiated in a solid water phantom to establish calibration curves in the dose range from 0.3 to 3 Gy for 6 and 18 MV X-ray beams from a clinical linear accelerator. Next, the dosimeters were placed at various locations in an anthropomorphic pelvic phantom to measure the dose delivery of a conventional four-field box technique treatment plan to the pelvis. Finally, the doses measured with alanine dosimeters were compared against the doses calculated with a commercial treatment planning system (TPS). The results showed that the alanine dosimeters have a highly sensitive dose response with good linearity and no energy dependence in the dose range and photon beams used in this work. Also, a fairly good agreement was found between the in-phantom dose measurements with alanine dosimeters and the TPS dose calculations. The mean value of the ratios of measured to calculated dose values was found to be near unity. The measured points in the in-field region passed dose-difference acceptance criterion of 3% and those in the penumbral region passed distance-to-agreement acceptance criterion of 3 mm. These findings suggest that the pure alanine powder in PMMA tube dosimeter is a suitable option for dosimetry of radiotherapy photon beams.

  10. Clinical experience with routine diode dosimetry for electron beam radiotherapy

    International Nuclear Information System (INIS)

    Yaparpalvi, Ravindra; Fontenla, Doracy P.; Vikram, Bhadrasain

    2000-01-01

    Purpose: Electron beam radiotherapy is frequently administered based on clinical setups without formal treatment planning. We felt, therefore, that it was important to monitor electron beam treatments by in vivo dosimetry to prevent errors in treatment delivery. In this study, we present our clinical experience with patient dose verification using electron diodes and quantitatively assess the dose perturbations caused by the diodes during electron beam radiotherapy. Methods and Materials: A commercial diode dosimeter was used for the in vivo dose measurements. During patient dosimetry, the patients were set up as usual by the therapists. Before treatment, a diode was placed on the patient's skin surface and secured with hypoallergenic tape. The patient was then treated and the diode response registered and stored in the patient radiotherapy system database via our in-house software. A customized patient in vivo dosimetry report showing patient details, expected and measured dose, and percent difference was then generated and printed for analysis and record keeping. We studied the perturbation of electron beams by diodes using film dosimetry. Beam profiles at the 90% prescription isodose depths were obtained with and without the diode on the beam central axis, for 6-20 MeV electron beams and applicator/insert sizes ranging from a 3-cm diameter circular field to a 25 x 25 cm open field. Results: In vivo dose measurements on 360 patients resulted in the following ranges of deviations from the expected dose at the various anatomic sites: Breast (222 patients) -20.3 to +23.5% (median deviation 0%); Head and Neck (63 patients) -21.5 to +14.8% (median -0.7%); Other sites (75 patients) -17.6 to +18.8% (median +0.5%). Routine diode dosimetry during the first treatment on 360 patients (460 treatment sites) resulted in 11.5% of the measurements outside our acceptable ±6% dose deviation window. Only 3.7% of the total measurements were outside ±10% dose deviation. Detailed

  11. Guide for everyday practice of in vivo dosimetry in external radiotherapy

    International Nuclear Information System (INIS)

    2008-01-01

    This guide first presents the objectives, methods and limitations of the In Vivo Dosimetry in external radiotherapy. Then, it describes the practical implementation of dosimetry with semiconductors (human needs, receipt tests, in vivo use, system quality control, semiconductor diodes). It also describes other available or currently being developed techniques (In vivo dosimetry using radio-thermoluminescent, MOSFET detectors or optically simulated luminescence). Finally, it present substitution methods when conventional In vivo dosimetry is not technically possible: transit dosimetry (with high energy imagery), global control of the treatment process

  12. Independent dose calculation of the Tps Iplan in radiotherapy conformed with MLC

    International Nuclear Information System (INIS)

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

    2014-08-01

    The systems utilization of independent dose calculation in three dimensional-Conformal Radiation Therapy (3D-Crt) treatments allows a direct verification of the treatments times. The utilization of these systems allows diminishing the probability of errors occurrence generated by the treatment planning system (Tps), allowing a detailed analysis of the dose to delivering and review of the normalization point (Np) or prescription. The independent dose calculation is realized across the knowledge of dosimetric parameters of the treatment machine and particular characteristics of every individual field. The aim of this work is develops a calculation system of punctual doses for isocentric fields conformed with multi-leaf collimation systems (MLC), where the dose calculation is in conformity with the suggested ones by ICRU Report No. 42, 1987. Calculation software was realized in C ++ under a free platform of programming (Code::Blocks). The system uses files in format Rtp, exported from the Tps to systems of record and verification (Lantis). This file contains detailed information of the dose, Um, position of the MLC sheets and collimators for every field of treatment. The size of equivalent field is obtained from the positions of every sheet; the effective depth of calculation can be introduced from the dosimetric report of the Tps or automatically from the DFS of the field. The 3D coordinates of the isocenter and the Np for the treatment plan must be introduced manually. From this information the system looks the dosimetric parameters and calculates the Um. The calculations were realized in two accelerators a NOVALIS Tx (Varian) with 120 sheets of high definition (hd-MLC) and a PRIMUS Optifocus (Siemens) with 82 sheets. 705 patients were analyzed for a total of 1082, in plans made for both equipment s, the average uncertainty with regard to the calculation of the Tps is-0.43% ± 2.42% in a range between [-7.90 %, 7.50 %]. The major uncertainty was in Np near of the

  13. Personalized dosimetry in internal radiotherapy with the help of voxelised phantoms; Dosimetrie personnalisee en radiotherapie interne a l'aide de fantomes voxelises

    Energy Technology Data Exchange (ETDEWEB)

    Chiavassa, S.; Bardies, M.; Martin, S.; Aubineau-Laniece, I. [Institut de Radioprotection et de Surete Nucleaire (IRSN/DPHD/SDOS/LEMDI), 92 - Fontenay-aux-Roses (France)

    2003-07-01

    The aim of this communication is to present a evaluation tool of the personalised internal dose that associated a Monte Carlo code to a voxelised representation of the patient for a personalised dosimetry evaluation in vectorized radiotherapy. the developments realised to reach a whole body dosimetry at tissue scale in a reasonable calculation time ( about a day) and some functionalities of the software are exposed. (N.C.)

  14. Pulse-resolved radiotherapy dosimetry using fiber-coupled organic scintillators

    DEFF Research Database (Denmark)

    Beierholm, Anders Ravnsborg

    This PhD project pertains to the development and adaptation of a dosimetry system that can be used to verify the delivery of radiation in modern radiotherapy modalities involving small radiation fields and dynamic radiation delivery. The dosimetry system is based on fibre-coupled organic scintill......This PhD project pertains to the development and adaptation of a dosimetry system that can be used to verify the delivery of radiation in modern radiotherapy modalities involving small radiation fields and dynamic radiation delivery. The dosimetry system is based on fibre-coupled organic...... millimeter, which is small enough to resolve the small radiation fields encountered in modern radiotherapy. The fast readout of the dosimeter enables measurements on the same time scale as the pulsed radiation delivery from the medical linear accelerators used for treatment. The dosimetry system, comprising...... for both standard and small fields. This thesis concludes that the new pulse-resolved dosimetry system holds great potential for modern radiotherapy applications, such as stereotactic radiotherapy and intensity-modulated radiotherapy....

  15. 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)

  16. Audit of radiotherapy dosimetry in New Zealand: Practical considerations and results

    International Nuclear Information System (INIS)

    Smyth, V.G.; Laban, J.A.

    2003-01-01

    In order to verify regulatory compliance, every two years staff of the National Radiation Laboratory (NRL) of New Zealand visit each of the radiotherapy departments in New Zealand to carry out an independent audit of the dosimetry of their external radiation beams. The audit is carried out under Technical Reports Series No. 277 reference conditions using dosimetry equipment belonging to the NRL to maximize the independence of the measurements. Audits have been carried out regularly since 1991 and the results show that discrepancies of up to 2% for linac beams are within normal output variability. However, much greater discrepancies are observed in kilovoltage X ray beams.This is due to the use of different dosimetry protocols rather than error. Experience to date suggests that the dosimetry audit is of continuing benefit to radiotherapy departments, but should be supplemented with dosimetry of planned treatments in an anthropomorphic phantom. (author)

  17. Clinical dosimetry in molecular radiotherapy: protocol optimization and clinical implementation

    International Nuclear Information System (INIS)

    Ferrer, Ludovic

    2011-01-01

    Molecular radiotherapy (mrt) consists in destructing tumour targets by radiolabelled vectors. This nuclear medicine specialty is being considered with increasing interest for example via the success achieved in the treatment of non-Hodgkin lymphomas by radioimmunotherapy. One of the keys of mrt optimization relies on the personalising of absorbed doses delivered to the patient: This is required to ascertain that irradiation is focused on tumour cells while keeping surrounding healthy tissue irradiation at an acceptable - non-toxic - level. Radiation dose evaluation in mrt requires in one hand, the spatial and temporal localization of injected radioactive sources by scintigraphic imaging, and on a second hand, the knowledge of the emitted radiation propagating media, given by CT imaging. Global accuracy relies on the accuracy of each of the steps that contribute to clinical dosimetry. There is no reference, standardized dosimetric protocol to date. Due to heterogeneous implementations, evaluation of the accuracy of the absorbed dose is a difficult task. In this thesis, we developed and evaluated different dosimetric approaches that allow us to find a relationship between the absorbed dose to the bone marrow and haematological toxicity. Besides, we built a scientific project, called DosiTest, which aims at evaluating the impact of the various step that contribute to the realization of a dosimetric study, by means of a virtual multicentric comparison based on Monte-Carlo modelling. (author) [fr

  18. Cuban experience in dosimetry quality audit program in radiotherapy

    International Nuclear Information System (INIS)

    Alonso-Samper, J.L.; Dominguez, L.; Yip, F.G.; Laguardia, R.A.; Morales, J.L.; Larrinaga, E.

    2002-01-01

    Full text: Five years ago we started a National Program of Quality Assurance in Radiotherapy. This program was possible thanks to the cooperation between the Cuban Ministry of Health and the International Atomic Energy Agency (IAEA) in the Projects ARCAL XXX and CUB/6/011. In the framework of these projects a total of ten complete dosimetry set were acquired and a large number of medical physicists were trained. At the same time, the Cuban side signed a contract for nine cobalt units, which have been gradually installed and all of them are running at the moment. During more than 20 years Cuba has taken part in the IAEA/WHO TLD postal dose audit programs and our results have been inside the (+/-)5 % acceptance limit. Cuba also joined the IAEA Coordinated Research Program E2 40 07, to extend at a national level the experience of the TLD based audits, using the capability of our SSDL to measure TLD. At the same time the work of the already existing External Audit Group was consolidated. The National Program of Quality Assurance in Radiotherapy works on base of external on-site visits. The main objective is to avoid any accident and to improve the quality of the RT treatments. Every year each Radiotherapy service is visited by a qualified team of physicists with the objective to check the physical aspects of the quality of the RT treatment, it includes: Documents and Records, safety, mechanical and dosimetric aspects, treatment planning, also we use the fixed depth phantom to simulate and verify several techniques. Although the TLD postal audit results are acceptable, in our QA audits we have detected some problems that may deviate the dose delivery to patients in more than 5%, examples of which are: Not all the clinical plans are redundantly checked by an independent person; Not all the controls (daily, monthly and annual) are performed according to the protocols approved by the National QA Committee. In some cases the controls are not well recorded; Clinical

  19. Independent dose calculation of the Tps Iplan in radiotherapy conformed with MLC; Calculo independiente de dosis del TPS Iplan en radioterapia conformada con MLC

    Energy Technology Data Exchange (ETDEWEB)

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

    2014-08-15

    The systems utilization of independent dose calculation in three dimensional-Conformal Radiation Therapy (3D-Crt) treatments allows a direct verification of the treatments times. The utilization of these systems allows diminishing the probability of errors occurrence generated by the treatment planning system (Tps), allowing a detailed analysis of the dose to delivering and review of the normalization point (Np) or prescription. The independent dose calculation is realized across the knowledge of dosimetric parameters of the treatment machine and particular characteristics of every individual field. The aim of this work is develops a calculation system of punctual doses for isocentric fields conformed with multi-leaf collimation systems (MLC), where the dose calculation is in conformity with the suggested ones by ICRU Report No. 42, 1987. Calculation software was realized in C ++ under a free platform of programming (Code::Blocks). The system uses files in format Rtp, exported from the Tps to systems of record and verification (Lantis). This file contains detailed information of the dose, Um, position of the MLC sheets and collimators for every field of treatment. The size of equivalent field is obtained from the positions of every sheet; the effective depth of calculation can be introduced from the dosimetric report of the Tps or automatically from the DFS of the field. The 3D coordinates of the isocenter and the Np for the treatment plan must be introduced manually. From this information the system looks the dosimetric parameters and calculates the Um. The calculations were realized in two accelerators a NOVALIS Tx (Varian) with 120 sheets of high definition (hd-MLC) and a PRIMUS Optifocus (Siemens) with 82 sheets. 705 patients were analyzed for a total of 1082, in plans made for both equipment s, the average uncertainty with regard to the calculation of the Tps is-0.43% ± 2.42% in a range between [-7.90 %, 7.50 %]. The major uncertainty was in Np near of the

  20. Optical fibre sensors: their role in in vivo dosimetry for prostate cancer radiotherapy.

    Science.gov (United States)

    Woulfe, P; Sullivan, F J; O'Keeffe, S

    2016-01-01

    Review is made of dosimetric studies of current optical fibre technology in radiotherapy for therapeutic applications, focusing particularly on in vivo dosimetry for prostate radiotherapy. We present the various sensor designs along with the main advantages and disadvantages associated with this technology. Optical fibres are ideally placed for applications in radiotherapy dosimetry; due to their small size they are lightweight and immune to electromagnetic interferences. The small dimensions of optical fibres allows it to be easily guided within existing brachytherapy equipment; for example, within the seed implantation needle for direct tumour dose analysis, in the urinary catheter to monitor urethral dose, or within the biopsy needle holder of the transrectal ultrasound probe to monitor rectal wall dose. The article presents the range of optical fibre dosimeter designs along with the main dosimetric properties required for a modern in vivo dosimetry system to be utilised in a clinical environment.

  1. Personalized dosimetry in internal radiotherapy with the help of voxelised phantoms

    International Nuclear Information System (INIS)

    Chiavassa, S.; Bardies, M.; Martin, S.; Aubineau-Laniece, I.

    2003-01-01

    The aim of this communication is to present a evaluation tool of the personalised internal dose that associated a Monte Carlo code to a voxelised representation of the patient for a personalised dosimetry evaluation in vectorized radiotherapy. the developments realised to reach a whole body dosimetry at tissue scale in a reasonable calculation time ( about a day) and some functionalities of the software are exposed. (N.C.)

  2. Characterisation of a CZT detector for dosimetry of molecular radiotherapy

    Science.gov (United States)

    McAreavey, L. H.; Harkness-Brennan, L. J.; Colosimo, S. J.; Judson, D. S.; Boston, A. J.; Boston, H. C.; Nolan, P. J.; Flux, G. D.; Denis-Bacelar, A. M.; Harris, B.; Radley, I.; Carroll, M.

    2017-03-01

    A pixelated cadmium zinc telluride (CZT) detector has been characterised for the purpose of developing a quantitative single photon emission computed tomography (SPECT) system for dosimetry of molecular radiotherapy (MRT). This is the aim of the Dosimetric Imaging with CZT (DEPICT) project, which is a collaboration between the University of Liverpool, The Royal Marsden Hospital, The Royal Liverpool and Broadgreen University Hospital, and the commercial partner Kromek. CZT is a direct band gap semiconductor with superior energy resolution and stopping power compared to scintillator detectors used in current SPECT systems. The inherent detector properties have been investigated and operational parameters such as bias voltage and peaking time have been selected to optimise the performance of the system. Good energy resolution is required to discriminate γ-rays that are scattered as they are emitted from the body and within the collimator, and high photon throughput is essential due to the high activities of isotopes administered in MRT. The system has an average measured electronic noise of 3.31 keV full width at half maximum (FWHM), determined through the use of an internal pulser. The energy response of the system was measured across the energy region of interest 59.5 keV to 364.5 keV and found to be linear. The reverse bias voltage and peaking time producing the optimum FWHM and maximum photon throughput were 600 V and 0.5 μs respectively. The average dead time of the system was measured as 4.84 μs and charge sharing was quantified to be 0.71 % at 59.5 keV . A pixel sensitivity calibration map was created and planar images of the medical imaging isotopes 99mTc and 123I were acquired by coupling the device to a prototype collimator, thereby demonstrating the suitability of the detector for the DEPICT project.

  3. Evaluation of electronic imaging device portal 'Portal Dosimetry' in quality control in intensity modulated radiotherapy

    International Nuclear Information System (INIS)

    Watanabe, Erika Yumi

    2010-01-01

    In this paper we present commissioning testing and evaluation of the use of Varian's portal dosimetry in the quality assurance of intensity-modulated radiotherapy. The commissioning tests were performed to characterize the portal dosimetry in terms dosimetric and to assess the its possible application in radiotherapy. These tests demonstrated that portal dosimetry has all the characteristics to be used for dosimetry in radiotherapy such as linear response with dose, the independence of dose rate, reproducibility, and others. The evaluation of the use of portal dosimetry in quality control of IMRT was performed in two steps: assessing the ability of the device to detect errors deliberately introduced in simple and complex fluences. Errors of known magnitude were introduced in certain areas of fluences and was carried out quality control of these fluences with portal dosimetry and three dosimetric systems: ionization chamber, film and array of ionization chambers. The data obtained from the portal were compared with those of other devices and all were able to identify errors introduced satisfactorily, the values, normalized to the original fluence, obtained with the portal dosimetry were similar to the ionization chamber and the array of ion chambers (seven29) and differing in up to 2% of the values obtained with the films. The fluences measured with the portal dosimetry were evaluated both quantitatively and qualitatively. The index of the gamma function provided by software analysis of portal dosimetry showed no defined rules of behavior in relation to the errors introduced and for this reason the qualitative analysis has proved indispensable in cases evaluated. (author)

  4. Contribution of customised dosimetry for small animal to the treatments of cancers by metabolic radiotherapy

    International Nuclear Information System (INIS)

    Boutaleb, Samir

    2010-01-01

    This research thesis first reports a bibliographical study which addressed the use of ionizing radiations in cancer therapy (evolution from ionizing radiation to metabolic radiotherapy, biological and physical parameters, and absorbed dose in metabolic radiotherapy) and the role imagery has in customised dosimetry (absorbed dose calculation methods, determination of cumulative activity, dosimetric models for S factor calculation). Then, the author presents a software which has been specifically developed for the creation of dosimetric models, and reports its validation. He reports the comparison between different dosimetric models in the case of mice. He highlights two applications of the developed tool: radio-immunotherapy and metabolic radiotherapy. He finally proposes a general discussion on the impact of small animal dosimetry on metabolic radiotherapy [fr

  5. Dosimetry-based treatment planning for molecular radiotherapy: a summary of the 2017 report from the Internal Dosimetry Task Force

    Directory of Open Access Journals (Sweden)

    Caroline Stokke

    2017-11-01

    Full Text Available Abstract Background The European directive on basic safety standards (Council directive 2013/59 Euratom mandates dosimetry-based treatment planning for radiopharmaceutical therapies. The directive comes into operation February 2018, and the aim of a report produced by the Internal Dosimetry Task Force of the European Association of Nuclear Medicine is to address this aspect of the directive. A summary of the report is presented. Results A brief review of five of the most common therapy procedures is included in the current text, focused on the potential to perform patient-specific dosimetry. In the full report, 11 different therapeutic procedures are included, allowing additional considerations of effectiveness, references to specific literature on quantitative imaging and dosimetry, and existing evidence for absorbed dose-effect correlations for each treatment. Individualized treatment planning with tracer diagnostics and verification of the absorbed doses delivered following therapy is found to be scientifically feasible for almost all procedures investigated, using quantitative imaging and/or external monitoring. Translation of this directive into clinical practice will have significant implications for resource requirements. Conclusions Molecular radiotherapy is undergoing a significant expansion, and the groundwork for dosimetry-based treatment planning is already in place. The mandated individualization is likely to improve the effectiveness of the treatments, although must be adequately resourced.

  6. Pre-evaluation of an ionization chamber for clinical radiotherapy dosimetry

    Energy Technology Data Exchange (ETDEWEB)

    Neves, Lucio P.; Perini, Ana P.; Xavier, Marcos; Caldas, Linda V.E., E-mail: mxavier@ipen.b, E-mail: lcaldas@ipen.b [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil); Khoury, Helen J., E-mail: khoury@ufpe.b [Universidade Federal de Pernambuco (UFPE), Recife, PE (Brazil). Dept. de Energia Nuclear

    2011-07-01

    This work presents some pre-operational tests for characterization of a new homemade ionization chamber developed at the Calibration Laboratory of Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP). This chamber was designed for use in radiotherapy dosimetry. To study the utilization of this chamber in radiotherapy, some tests were undertaken: short- and medium-term stabilities, saturation curve, recombination loss, polarity effect and leakage current. All results obtained in these tests were within the international recommendations. (author)

  7. The 2009 survey of therapy equipment and dosimetry practices in Australian radiotherapy centres

    International Nuclear Information System (INIS)

    Brown, Rhonda L.; Butler, Duncan J.

    2010-01-01

    Full text: The results of a recent survey of Australian radiotherapy centres are presented. A total of 56 treatment centres were identified, operating 139 linacs, 26 k V units and 25 remote afterloaders. Of these centres, 51 partici pated in the survey (91 %). Results are presented which summarize the beam qualities, dosimetry protocols, ion chambers and treatment modalities in clinical use. The results provide a snapshot of the equipment and practices used in radiotherapy in Australia in 2009.

  8. Dosimetry on the radiological risks prevention in radiotherapy; La dosimetria en la prevencion de riesgos radiologicos en radioterapia

    Energy Technology Data Exchange (ETDEWEB)

    Fornet R, O. M.; Perez G, F., E-mail: nuclear2@citmahlg.holguin.inf.cu [Delegacion Territorial del CITMA, Peralta 16 esq. P. Feria, Rpto. Peralta, 80400 Holguin (Cuba)

    2014-08-15

    Dosimetry in its various forms plays a determining role on the radiological risks prevention in radiotherapy. To prove this in this paper is shown an analysis based on the risk matrix method, how the dosimetry can influence in each stages of a radiotherapy service; installation and acceptance, operation, maintenance and calibration. For each one of these stages the role that can play is analyzed as either the initiating event of a radiological accident or limiting barrier of these events of the dosimetric processes used for the individual dosimetry, the area monitoring, fixed or portable, for radiation beam dosimetry and of the patients for a radiotherapy service with cobalt-therapy equipment. The result of the study shows that the application of a prospective approach in the role evaluation of dosimetry in the prevention and mitigation of the consequences of a radiological accident in radiotherapy is crucial and should be subject to permanent evaluation at each development stage of these services. (author)

  9. 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)

  10. Characterizing a pulse-resolved dosimetry system for complex radiotherapy beams using organic scintillators

    DEFF Research Database (Denmark)

    Beierholm, Anders Ravnsborg; Ottosson, Rickard; Lindvold, Lars René

    2011-01-01

    A fast-readout dosimetry system based on fibre-coupled organic scintillators has been developed for the purpose of conducting point measurements of absorbed dose in radiotherapy beams involving high spatial and temporal dose gradients. The system measures the dose for each linac radiation pulse w...... and quality assurance of complex radiotherapy treatments.......A fast-readout dosimetry system based on fibre-coupled organic scintillators has been developed for the purpose of conducting point measurements of absorbed dose in radiotherapy beams involving high spatial and temporal dose gradients. The system measures the dose for each linac radiation pulse....... No significant differences between measurements and simulations were observed. The temporal resolution of the system was demonstrated by measuring dose per pulse, beam start-up transients and the quality factor for 6 MV. The precision of dose per pulse measurements was within 2.7% (1 SD) for a 10 cm × 10 cm...

  11. Synthetic diamond devices for medical dosimetry applied to radiotherapy; Etude et developpement de dispositifs en diamant synthetique pour la dosimetrie medicale: applications en radiotherapie

    Energy Technology Data Exchange (ETDEWEB)

    Descamps, C

    2007-06-15

    The aim of this thesis, lead in the framework of an integrated European project entitled M.A.E.S.T.R.O. for ' Methods and Advanced Equipment for Simulation and Treatment in Radio Oncology', was to develop and test synthetic diamond detector in clinical environment for new modalities used in radiotherapy. Diamond is a good candidate for the detection of high energy beams in medical fields. It can be used for passive dosimetry, as thermoluminescent dosimeters or for active dosimetry as ionisation chambers. These two applications are presented here. Concerning the thermoluminescence, several impurities or dopants (boron, phosphorus, and nitrogen) have been incorporated in the diamond films during growth, in order to modify the material dosimetric properties and a detailed study of nitrogen-containing films is proposed. The second part presents the results obtained in active dosimetry. Two guide lines were followed: the measurement set-up optimisation and the material modification. The first dosimetric studies under radiotherapy beams concerning nitrogen-containing polycrystalline diamond as well as high purity single crystal diamond are conclusive. The detectors behaviours are in agreement with the recommendations of the International Atomic Energy Agency (IAEA). (author)

  12. A methodology for dosimetry audit of rotational radiotherapy using a commercial detector array

    International Nuclear Information System (INIS)

    Hussein, Mohammad; Tsang, Yatman; Thomas, Russell A.S.; Gouldstone, Clare; Maughan, David; Snaith, Julia A.D.; Bolton, Steven C.; Nisbet, Andrew; Clark, Catharine H.

    2013-01-01

    Purpose: To develop a methodology for the use of a commercial detector array in dosimetry audits of rotational radiotherapy. Materials and methods: The methodology was developed as part of the development of a national audit of rotational radiotherapy. Ten cancer centres were asked to create a rotational radiotherapy treatment plan for a three-dimensional treatment-planning-system (3DTPS) test and audited. Phantom measurements using a commercial 2D ionisation chamber (IC) array were compared with measurements using 0.125 cm 3 IC, Gafchromic film and alanine pellets in the same plane. Relative and absolute gamma index (γ) comparisons were made for Gafchromic film and 2D-Array planes, respectively. Results: Comparisons between individual detectors within the 2D-Array against the corresponding IC and alanine measurement showed a statistically significant concordance correlation coefficient (both ρ c > 0.998, p < 0.001) with mean difference of −1.1 ± 1.1% and −0.8 ± 1.1%, respectively, in a high dose PTV. In the γ comparison between the 2D-Array and film it was that the 2D-Array was more likely to fail planes where there was a dose discrepancy due to the absolute analysis performed. Conclusions: It has been found that using a commercial detector array for a dosimetry audit of rotational radiotherapy is suitable in place of standard systems of dosimetry

  13. Pulse-resolved radiotherapy dosimetry using fiber-coupled organic scintillators

    International Nuclear Information System (INIS)

    Ravnsborg Beierholm, A.

    2011-05-01

    This PhD project pertains to the development and adaptation of a dosimetry system that can be used to verify the delivery of radiation in modern radiotherapy modalities involving small radiation fields and dynamic radiation delivery. The dosimetry system is based on fibre-coupled organic scintillators and can be perceived as a well characterized, independent alternative to the methods that are in clinical use today. The dosimeter itself does not require a voltage supply, and is composed of water equivalent materials. The dosimeter can be fabricated with a sensitive volume smaller than a cubic millimeter, which is small enough to resolve the small radiation fields encountered in modern radiotherapy. The fast readout of the dosimeter enables measurements on the same time scale as the pulsed radiation delivery from the medical linear accelerators used for treatment. The dosimetry system, comprising fiber-coupled organic scintillators and data acquisition hardware, was developed at the Radiation Research Division at Risoe DTU and tested using clinical x-ray beams at hospitals in Denmark and abroad. Measurements of output factors and percentage depth dose were performed and compared with reference values and Monte Carlo simulations for static square radiation fields for standard (4 cm x 4 cm to 20 cm x 20 cm) and small (down to 0.6 cm x 0.6 cm) field sizes. The accuracy of most of the obtained measurements was good, agreeing with reference and simulated dose values to within 2 % standard deviation for both standard and small fields. This thesis concludes that the new pulse-resolved dosimetry system holds great potential for modern radiotherapy applications, such as stereotactic radiotherapy and intensity-modulated radiotherapy. (Author)

  14. Pulse-resolved radiotherapy dosimetry using fiber-coupled organic scintillators

    Energy Technology Data Exchange (ETDEWEB)

    Ravnsborg Beierholm, A.

    2011-05-15

    This PhD project pertains to the development and adaptation of a dosimetry system that can be used to verify the delivery of radiation in modern radiotherapy modalities involving small radiation fields and dynamic radiation delivery. The dosimetry system is based on fibre-coupled organic scintillators and can be perceived as a well characterized, independent alternative to the methods that are in clinical use today. The dosimeter itself does not require a voltage supply, and is composed of water equivalent materials. The dosimeter can be fabricated with a sensitive volume smaller than a cubic millimeter, which is small enough to resolve the small radiation fields encountered in modern radiotherapy. The fast readout of the dosimeter enables measurements on the same time scale as the pulsed radiation delivery from the medical linear accelerators used for treatment. The dosimetry system, comprising fiber-coupled organic scintillators and data acquisition hardware, was developed at the Radiation Research Division at Risoe DTU and tested using clinical x-ray beams at hospitals in Denmark and abroad. Measurements of output factors and percentage depth dose were performed and compared with reference values and Monte Carlo simulations for static square radiation fields for standard (4 cm x 4 cm to 20 cm x 20 cm) and small (down to 0.6 cm x 0.6 cm) field sizes. The accuracy of most of the obtained measurements was good, agreeing with reference and simulated dose values to within 2 % standard deviation for both standard and small fields. This thesis concludes that the new pulse-resolved dosimetry system holds great potential for modern radiotherapy applications, such as stereotactic radiotherapy and intensity-modulated radiotherapy. (Author)

  15. GATE: computation code for medical imagery, radiotherapy and dosimetry

    International Nuclear Information System (INIS)

    Jan, S.

    2010-01-01

    The author presents the GATE code, a simulation software based on the Geant4 development environment developed by the CERN (the European organization for nuclear research) which enables Monte-Carlo type simulation to be developed for tomography imagery using ionizing radiation, and radiotherapy examinations (conventional and hadron therapy) to be simulated. The authors concentrate on the use of medical imagery in carcinology. They comment some results obtained in nuclear imagery and in radiotherapy

  16. Radiotherapy dosimetry audit: three decades of improving standards and accuracy in UK clinical practice and trials.

    Science.gov (United States)

    Clark, Catharine H; Aird, Edwin G A; Bolton, Steve; Miles, Elizabeth A; Nisbet, Andrew; Snaith, Julia A D; Thomas, Russell A S; Venables, Karen; Thwaites, David I

    2015-01-01

    Dosimetry audit plays an important role in the development and safety of radiotherapy. National and large scale audits are able to set, maintain and improve standards, as well as having the potential to identify issues which may cause harm to patients. They can support implementation of complex techniques and can facilitate awareness and understanding of any issues which may exist by benchmarking centres with similar equipment. This review examines the development of dosimetry audit in the UK over the past 30 years, including the involvement of the UK in international audits. A summary of audit results is given, with an overview of methodologies employed and lessons learnt. Recent and forthcoming more complex audits are considered, with a focus on future needs including the arrival of proton therapy in the UK and other advanced techniques such as four-dimensional radiotherapy delivery and verification, stereotactic radiotherapy and MR linear accelerators. The work of the main quality assurance and auditing bodies is discussed, including how they are working together to streamline audit and to ensure that all radiotherapy centres are involved. Undertaking regular external audit motivates centres to modernize and develop techniques and provides assurance, not only that radiotherapy is planned and delivered accurately but also that the patient dose delivered is as prescribed.

  17. SFPM opinion on the so-called 'transit' in vivo dosimetry in external radiotherapy

    International Nuclear Information System (INIS)

    Berger, Lucie; Dupuis, Pauline; Marchesi, Vincent; Boutry, Christine; Francois, Pascal; Crespin, Sylvain

    2014-01-01

    Written to the demand of the ASN to the SFPM (the French professional body in medical physics), this report states the opinion of these professionals regarding the use of the so-called 'transit' dosimetry for the control of the in vivo dose received during radiotherapy. After an overview of the use of in vivo dosimetry in medical practices, the authors outline the main benefits and drawbacks of point conventional detectors used for this dosimetry. They propose an overview of the state-of-the-art in transit in vivo dosimetry by briefly describing the different developed methodologies: the prediction-based methodology and the rear projection methodology. They also propose a literature review on transit in vivo dosimetry. Based on expert experience and on this review they give lists of technical benefits and drawbacks of techniques of in vivo dosimetry by EPID transit imagery. They finally indicate some commercially available technical solutions to transit in vivo dosimetry

  18. The role of the national physical laboratory in monitoring and improving dosimetry in UK radiotherapy

    International Nuclear Information System (INIS)

    McEwen, M.R.; Duane, S.; Thomas, R.A.S.; Rosser, K.E.

    2001-01-01

    There are approximately 60 radiotherapy centres in the UK. In 1999, these centres carried out over 102,000 treatments in 1.2 million fractions. These centres are organised by IPEM into eight geographical regions for the purpose of inter-departmental audits, which have been carried out on a regular basis to check the uniformity of dosimetry, treatment planning, record keeping, etc. Thwaites et al (1992) carried out a dosimetric intercomparison of megavoltage photon beams in all UK radiotherapy centres obtaining a mean value for the ratio audit/local dose of 1.003 with a standard deviation of 1.5%. The present programme covers dosimetry of megavoltage photons and electrons and low and medium energy (10-300 kV) photons. Megavoltage photon audits have the longest history, while electron audits began in 2000 and kV audits are only at the pilot stage

  19. 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

  20. Dosimetry comparison of irradiation with conformal radiotherapy, intensity modulated radiotherapy, conformal radiotherapy in stereotactic conditions and robotic stereotactic radiotherapy for benign brain tumours

    International Nuclear Information System (INIS)

    Spasic, E.; Noel, A.; Buchheit, I.; Bernier, V.

    2011-01-01

    Purpose. - To compare several techniques in order to determine the best treatment for benign brain tumours. Methods and patients. - A retrospective study was performed for five patients who received 3D-conformal radiotherapy, intensity modulated radiotherapy or CyberKnife R . These patients had a meningioma, a pituitary tumour, a cranio-pharyngioma or a neurinoma. In each case, these treatment plans were optimised and compared with the three other dosimetries. Radiobiological or positioning parameters were evaluated, as well as dosimetric parameters, in order to compare treatments with different characteristics. Results. - The dosimetric parameters showed that the choice of treatment seemed to be determined mostly by tumour size, shape and proximity with organs at risk (not tumour localisation). Whereas the results showed no significant deviations with regards to the radiobiological parameters. Therefore, with these parameters, it was difficult to give priority to a treatment. Conclusions. - With regards to benign brain tumours of medium or large size, intensity modulated radiotherapy seemed the recommended treatment. It enabled to obtain a good ratio between efficacy and toxicity for tumours that are really close to organs at risk. Concerning small benign brain tumours, the CyberKnife R was probably the best treatment. (authors)

  1. Radiological response and dosimetry in physical phantom of head and neck for 3D conformational radiotherapy; Resposta radiologica e dosimetria em phantom fisico de cabeca e pescoco para radioterapia conformacional 3D

    Energy Technology Data Exchange (ETDEWEB)

    Thompson, Larissa

    2013-07-01

    Phantoms are tools for simulation of organs and tissues of the human body in radiology and radiotherapy. This thesis describes the development, validation and, most importantly, the use of a physical head and neck phantom in radiology and radiotherapy, with the purpose of evaluating dose distribution using Gafchromic EBT2 film in 15 MV 3D conformal radiotherapy. The work was divided in two stages, (1) development of new equivalent tissues and improvement of the physical phantom, and (2) use of the physical phantom in experimental dosimetry studies. In phase (1) parameters such as mass density, chemical composition of tissues, anatomical and biometric measurements were considered, as well as aspects of imaging by computed tomography (CT) and radiological response representation in Hounsfield Units (HU), which were compared with human data. Radiological experiments of in-phantom simulated brain pathologies were also conducted. All those results matched human-sourced data, therefore the physical phantom is a suitable simulator that may be used to enhance radiological protocols and education in medical imaging. The main objective in phase (2) was to evaluate the spatial dose distribution in a brain tumor simulator inserted inside the head and neck phantom developed by the Ionizing Radiation Research Group (NRI), exposed to 15 MV 3D conformal radiotherapy, for internal dose assessment. Radiation planning was based on CT images of the physical phantom with a brain tumor simulator made with equivalent material. The treatment planning system (TPS), CAT3D software, used CT images and prescribed a dose of 200 cGy, distributed in three fields of radiation, in a T-shaped pattern. The TPS covered the planning treatment volume (PTV) with 97% of the prescribed dose. A solid water phantom and radiochromic Gafchromic EBT2 film were used for calibration procedures, generating a dose response curve as a function of optical density (OD). After calibration and irradiation, the film

  2. A review of recent advances in optical fibre sensors for in vivo dosimetry during radiotherapy.

    Science.gov (United States)

    O'Keeffe, S; McCarthy, D; Woulfe, P; Grattan, M W D; Hounsell, A R; Sporea, D; Mihai, L; Vata, I; Leen, G; Lewis, E

    2015-06-01

    This article presents an overview of the recent developments and requirements in radiotherapy dosimetry, with particular emphasis on the development of optical fibre dosemeters for radiotherapy applications, focusing particularly on in vivo applications. Optical fibres offer considerable advantages over conventional techniques for radiotherapy dosimetry, owing to their small size, immunity to electromagnetic interferences, and suitability for remote monitoring and multiplexing. The small dimensions of optical fibre-based dosemeters, together with being lightweight and flexible, mean that they are minimally invasive and thus particularly suited to in vivo dosimetry. This means that the sensor can be placed directly inside a patient, for example, for brachytherapy treatments, the optical fibres could be placed in the tumour itself or into nearby critical tissues requiring monitoring, via the same applicators or needles used for the treatment delivery thereby providing real-time dosimetric information. The article outlines the principal sensor design systems along with some of the main strengths and weaknesses associated with the development of these techniques. The successful demonstration of these sensors in a range of different clinical environments is also presented.

  3. In vivo dosimetry with diodes in a radiotherapy department in Pakistan.

    Science.gov (United States)

    Tunio, Mutahir; Rafi, Mansoor; Ali, Shoukat; Ahmed, Zaeem; Zameer, Asad; Hashmi, Altaf; Maqbool, Syed A

    2011-11-01

    The International Commission of Radiological Units (ICRU) sets a tolerance of ±5 % on dose delivery, with more recent data limiting the overall tolerances to ±3 %. One of the best methods for accurate dose delivery and quality check is in vivo dosimetry, while radiotherapy is performed. The present study was carried out to test the applicability of diodes for performing in vivo entrance dose measurements in external photon beam radiotherapy for pelvic tumours and its implementation as quality assurance tool in radiotherapy. During November 2007 to December 2009, in 300 patients who received pelvic radiotherapy on a multileaf-collimator-assisted linear accelerator, the central axis dose was measured by in vivo dosimetry by p-Si diodes. Entrance dose measurements were taken by diodes and were compared with the prescribed dose. Totally 1000 calculations were performed. The mean and standard deviation between measured and prescribed dose was 1.26 ± 2.8 %. In 938 measurements (93.8 %), the deviation was 5 % (5.51 ± 2.3 %). Larger variations were seen in lateral and oblique fields more than anteroposterior fields. For larger deviations, patients and diode positional errors were found to be the common factors alone or in combination with other factors. After additional corrections, repeated measurements were achieved within tolerance levels. This study showed that diode-detector-based in vivo dosimetry was simple, cost-effective, provides quick results and can serve as a useful quality assurance tool in radiotherapy. The data acquired in the present study can be used for evaluating output calibration of therapy machine, precision of calculations, effectiveness of treatment plan and patient setup.

  4. Dosimetry at the location of secondary tumors after radiotherapy

    Energy Technology Data Exchange (ETDEWEB)

    Baas, H.W.; Davelaar, J.J.; Broerse, J.J.; Noordijk, E.M. [University Hospital, Leiden (Netherlands). Dept. of Clinical Oncology

    1995-12-01

    After a latency period of many years the incidence of a secondary tumor is considered a serious late effect of radiotherapy. Analysis of about 200 patients, treated by radiotherapy for Hodgkin`s disease in our hospital, shows an actuarial risk for the incidence of a secondary tumor of about 7% after 10 years. The chance of tumor induction depends on the dose at the location of the tumor and therefore a good dose estimation is mandatory. Radiotherapy was given with Co-60 in the early years and with linear accelerators thereafter, exposing the target areas to 36 - 40 Gy. For dose estimations at the penumbra and outside the beam, where tumor incidence is expected to be high, we used a.o. Monte Carlo calculations. We developed an EGS4 computer simulation for a treatment beam from a linear accelerator irradiating a mathematical phantom representing the patient geometry (GSF ADAM phantom). The isodose curves at certain energies were obtained for a water phantom and fitted quite well with measurements. In addition to Monte Carlo calculations we also used existing treatment planning systems. The dose estimations of a number of patients and the derived risk per unit of dose, which is important for both radiotherapy as well as radiation protection in general, is discussed.

  5. A multicentre 'end to end' dosimetry audit of motion management (4DCT-defined motion envelope) in radiotherapy.

    Science.gov (United States)

    Palmer, Antony L; Nash, David; Kearton, John R; Jafari, Shakardokht M; Muscat, Sarah

    2017-12-01

    External dosimetry audit is valuable for the assurance of radiotherapy quality. However, motion management has not been rigorously audited, despite its complexity and importance for accuracy. We describe the first end-to-end dosimetry audit for non-SABR (stereotactic ablative body radiotherapy) lung treatments, measuring dose accumulation in a moving target, and assessing adequacy of target dose coverage. A respiratory motion lung-phantom with custom-designed insert was used. Dose was measured with radiochromic film, employing triple-channel dosimetry and uncertainty reduction. The host's 4DCT scan, outlining and planning techniques were used. Measurements with the phantom static and then moving at treatment delivery separated inherent treatment uncertainties from motion effects. Calculated and measured dose distributions were compared by isodose overlay, gamma analysis, and we introduce the concept of 'dose plane histograms' for clinically relevant interpretation of film dosimetry. 12 radiotherapy centres and 19 plans were audited: conformal, IMRT (intensity modulated radiotherapy) and VMAT (volumetric modulated radiotherapy). Excellent agreement between planned and static-phantom results were seen (mean gamma pass 98.7% at 3% 2 mm). Dose blurring was evident in the moving-phantom measurements (mean gamma pass 88.2% at 3% 2 mm). Planning techniques for motion management were adequate to deliver the intended moving-target dose coverage. A novel, clinically-relevant, end-to-end dosimetry audit of motion management strategies in radiotherapy is reported. Copyright © 2017 Elsevier B.V. All rights reserved.

  6. Cardiovascular dosimetry using hybrid computational phantoms after external radiotherapy

    International Nuclear Information System (INIS)

    Moignier, Alexandra

    2014-01-01

    Cardiovascular diseases following radiotherapy are major secondary late effects raising questions among the scientific community, especially regarding the dose-effect relationship and confounding risk factors (chemotherapy, cholesterolemia, age at treatment, blood pressure,..). Post-radiation coronary diseases are one of the main causes of cardiac morbidity. Some approximations are made when coronary doses due to radiotherapy are estimated, especially regarding the morphology. For retrospective studies with old medical records, only radiographs are usually available with sometimes some contours made with a simulator. For recent medical records, CT scans displaying the anatomy in 3D are used for radiotherapy simulation but do not allow the coronary artery visualization due to low resolution and contrast. Currently, coronary doses are barely assessed in clinical practice, and when it is done, anatomical prior knowledge is generally used. This thesis proposes an original approach based on hybrid computational phantoms to study coronary artery doses following radiotherapy for left-side breast cancer and Hodgkin lymphoma. During the thesis, a method inserting hybrid computational phantoms in a DICOM format into the treatment planning system has been developed and validated. It has been adapted and tested in conditions where only radiographs provide anatomical information, as with old medical records for left side breast radiotherapy. The method has also been adapted to perform precise dose reconstructions to the coronary artery for patients treated for a mediastinal Hodgkin lymphoma and diagnosed with coronary stenosis through a coro-scanner. A case-control study was carried out and the risk of coronary stenosis on a coronary artery segment was assessed to be multiplied by 1.049 at each additional gray on the median dose to the coronary artery segment. For recent medical records, coronary doses uncertainties related to an approach by anatomical prior knowledge

  7. Heart dosimetry in radiotherapy with hybrid computational phantoms

    International Nuclear Information System (INIS)

    Moignier, Cyril

    2014-01-01

    Cardiovascular diseases following radiotherapy are major secondary late effects raising questions among the scientific community, especially regarding the dose-effect relationship and confounding risk factors (chemotherapy, cholesterolemia, age at treatment, blood pressure,..). Post-radiation coronary diseases are one of the main causes of cardiac morbidity. Some approximations are made when coronary doses due to radiotherapy are estimated, especially regarding the morphology. For retrospective studies with old medical records, only radiographs are usually available with sometimes some contours made with a simulator. For recent medical records, CT scans displaying the anatomy in 3D are used for radiotherapy simulation but do not allow the coronary artery visualization due to low resolution and contrast. Currently, coronary doses are barely assessed in clinical practice, and when it is done, anatomical prior knowledge is generally used. This thesis proposes an original approach based on hybrid computational phantoms to study coronary artery doses following radiotherapy for left-side breast cancer and Hodgkin lymphoma. During the thesis, a method inserting hybrid computational phantoms in a DICOM format into the treatment planning system has been developed and validated. It has been adapted and tested in conditions where only radiographs provide anatomical information, as with old medical records for left side breast radiotherapy. The method has also been adapted to perform precise dose reconstructions to the coronary artery for patients treated for a mediastinal Hodgkin lymphoma and diagnosed with coronary stenosis through a coroscanner. A case-control study was carried out and the risk of coronary stenosis on a coronary artery segment was assessed to be multiplied by 1.049 at each additional gray on the median dose to the coronary artery segment. For recent medical records, coronary doses uncertainties related to an approach by anatomical prior knowledge

  8. Treatment planning and dosimetry in radiotherapy for glottic cancer

    International Nuclear Information System (INIS)

    Fukudomi, Yukimi; Kawakami, Toshiaki; Fujii, Takashi; Kawamura, Masashi; Kataoka, Masaaki; Hamamoto, Ken

    1995-01-01

    To perform a precise radiotherapy and to prevent local failure as low as possible for early glottic cancer, we present data regarding the technical basis of radiotherapy. Thermoluminescent dosimeters (TLDs) were embedded at 6 locations in a hand-made Mix-Dp phantom and exposed to two lateral-opposed beams using 6 x 6 cm 2 fields. The dosimeters were irradiated using 4 MV-X, 6 MV-X and 10 MV-X with open-field, 15deg and 30deg wedge filter (WF) made of Pb or Fe, and a hand-made Mix-Dp WF compensating irregular skin surface which was placed apart from the patient's skin to preserve skin-sparing properties. Calculation of absorbed dose with a computer for treatment planning was performed. Using 6 MV-X and a 30deg WF, the dose distribution was the best in this phantom. With 10 MV-X, the absorbed dose at the anterior glottis was 6.7-11.6% lower than the administered dose. Using a Mix-Dp WF, the dose distribution was better than those using WF made of Pb or Fe. Under various types of treatments, the absorbed dose at the reference point using TLDs were 0.4-5.8% lower than the administered dose calculated with ratio-TAR method at the same point. These are believed to be due to lack of estimation of scatters and poor correcting method for WF factor. We conclude that some experimental checks are desirable to perform a precise radiotherapy for laryngeal cancer. This can be done using a number of TLDs placed at points of interest in a phantom. (author)

  9. EPR dosimetry of radiotherapy photon beams in inhomogeneous media using alanine films

    International Nuclear Information System (INIS)

    Oesteraas, Bjoern Helge; Hole, Eli Olaug; Olsen, Dag Rune; Malinen, Eirik

    2006-01-01

    In the current work, EPR (electron paramagnetic resonance) dosimetry using alanine films (134 μm thick) was utilized for dose measurements in inhomogeneous phantoms irradiated with radiotherapy photon beams. The main phantom material was PMMA, while either Styrofoam or aluminium was introduced as an inhomogeneity. The phantoms were irradiated to a maximum dose of about 30 Gy with 6 or 15 MV photons. The performance of the alanine film dosimeters was investigated and compared to results from ion chamber dosimetry, Monte Carlo simulations and radiotherapy treatment planning calculations. It was found that the alanine film dosimeters had a linear dose response above approximately 5 Gy, while a background signal obscured the response at lower dose levels. For doses between 5 and 60 Gy, the standard deviation of single alanine film dose estimates was about 2%. The alanine film dose estimates yielded results comparable to those from the Monte Carlo simulations and the ion chamber measurements, with absolute differences between estimates in the order of 1-15%. The treatment planning calculations exhibited limited applicability. The current work shows that alanine film dosimetry is a method suitable for estimating radiotherapeutical doses and for dose measurements in inhomogeneous media

  10. Evaluation of radiochromic films EBT3 for in-vivo dosimetry in radiotherapy treatments with photons

    International Nuclear Information System (INIS)

    Galvan de la C, O. O.; Rivera M, T.; Garcia G, O. A.; Larraga G, J. M.

    2015-10-01

    Full text: In-vivo dosimetry is a challenge in radiotherapy due to the measures are carried out in reference conditions outside; there is no balance of charged particle and beam consists of photons own and contamination electrons. Detectors that are useful for such measures should be sufficiently small and thin so they do not disturb the beam and do not alter the dose on target. In this paper the radiochromic films Gafchromic model EBT3 are evaluated as potential detectors for in-vivo dosimetry; measurements were carried out in solid water phantom on the surface, with films of dimensions 3 x 3 cm 2 . Irradiations were performed with a linear accelerator Novalis of 6 MV. Comparison between dose values found with a diode type Sfd detector (IBA dosimetry, Germany) and a diamond detector CVD (PTW-Freiburg) for 2 different sized of field (5 x 5 cm 2 and 10 x 10 cm 2 ) on the surface of a water phantom scanning was realized. The total spreading factor (Tsf) measured on surface was of 0.831 ± 4.6%; which is greater 12.9% than Tsf measured at a depth of maximum dose. This difference may be due to the contribution of scattered electrons to the beam exit. The measures must be corroborated with Monte Carlo simulations, which they will be validated on surface by the Abdel-Rahman [et al.] method; this mechanism will determine if the films are useful detectors for in-vivo dosimetry clinically. (Author)

  11. Accuracy required and achievable in radiotherapy dosimetry: have modern technology and techniques changed our views?

    Science.gov (United States)

    Thwaites, David

    2013-06-01

    In this review of the accuracy required and achievable in radiotherapy dosimetry, older approaches and evidence-based estimates for 3DCRT have been reprised, summarising and drawing together the author's earlier evaluations where still relevant. Available evidence for IMRT uncertainties has been reviewed, selecting information from tolerances, QA, verification measurements, in vivo dosimetry and dose delivery audits, to consider whether achievable uncertainties increase or decrease for current advanced treatments and practice. Overall there is some evidence that they tend to increase, but that similar levels should be achievable. Thus it is concluded that those earlier estimates of achievable dosimetric accuracy are still applicable, despite the changes and advances in technology and techniques. The one exception is where there is significant lung involvement, where it is likely that uncertainties have now improved due to widespread use of more accurate heterogeneity models. Geometric uncertainties have improved with the wide availability of IGRT.

  12. Calculation of uncertainties in the protocol of dosimetry for Co 60 beams in Radiotherapy

    International Nuclear Information System (INIS)

    Velazquez M, S.; Carrera M, F.; Sanchez S, J.

    1998-01-01

    The objective in this work is to show how the uncertainty is possible to know in the determination of the absorbed dose in Co 60 photon beams and to establish in a rational form, tolerance levels for this. It is took as base the spanish protocol of dosimetry in Radiotherapy. We have been centered in a Co 60 beam. We utilized the statistical theory of little samples. We allowed to suggest a new approach about the treatment of the tolerance levels and the uncertainty of the measurement. After two years of experience in the practical hospitable application we have gotten to put around 1 % uncertainty in the absolute dosimetry of the Co 60 beam. The presented protocol allows to execute the accuracy requirements in the determination of absorbed doses. (Author)

  13. Quality control of radiotherapy centres in the Slovak Republic: a dosimetry intercomparison of photon and electron beams under reference conditions

    International Nuclear Information System (INIS)

    Gomola, I.; Kralik, G.; Laginova, V.; Van Dam, J.

    2001-01-01

    The aim of this paper is a dosimetry intercomparison of photon and electron beams under reference conditions as well as quality control of radiotherapy centres in the Slovak Republic. The results obtained in the first check shows that only about 60% of beams are within the acceptance limit. The reasons of discrepancies were traced, in some cases by an on site visit of experts from the NRC, and unacceptable deviations were corrected. The results clearly demonstrate the usefulness of the external dosimetry checks performed with the mailed thermoluminescent dosimeters. Standard deviation of the distribution of the results decreased from SD=4.3% to SD=I.8% for checked photon beams and from SD=8.6% to SD=2.4% for electron beams, respectively, at the end of the project. The dosimetry audits which are performed in regular intervals significantly decreasing a possibility of mistreatment (under-dosage or over-dosage ) of patients due to wrong calibration of radiation therapy beams. In order to keep the reached level of dosimetry precision, it is necessary to establish the external audit in radiotherapy at the national level based on postal TLD dosimetry by transferring the know-how from the international program on quality assurance in radiotherapy dosimetry with the assistance of the IAEA. (authors)

  14. The potential application of silver and positron emission tomography for in vivo dosimetry during radiotherapy

    DEFF Research Database (Denmark)

    Hansen, Anders T; Hansen, Søren B; Petersen, Jørgen B

    2007-01-01

    The possible use of silver as a material for in vivo dosimetry in radiotherapy was investigated. The investigation was carried out using a positron emission tomography (PET) scanner, two clinical accelerators and a phantom with silver implants. The phantom was irradiated several times to doses...... between 6 and 45 Gy. The resulting activity of positron-emitting isotopes produced in the silver by photonuclear processes was measured. It was found that the two therapeutic beams with energies of 15 MV and 18 MV would produce approximately 8344 and 7013 atoms of the radioactive isotope (106)Ag per Gy...

  15. Radiochromic film dosimetry of contrast-enhanced radiotherapy (CERT)

    International Nuclear Information System (INIS)

    Morris, Kevin N; Weil, Michael D; Malzbender, Rainer

    2006-01-01

    Contrast-enhanced radiotherapy (CERT) employs elevated concentrations of high-Z contrast media in targets to dramatically increase the absorbed dose of radiation relative to the surrounding tissues. However, it is difficult to measure the dose enhancement with routine clinical instruments because the photoelectrons and Auger electrons produced by the interaction of kilovoltage x-rays with the contrast agent travel extremely short distances. We have developed a technique utilizing unlaminated radiochromic film to measure the maximum dose enhancement factor attainable in solutions of contrast agent with iodine concentrations ranging from 0% to 37% (w/v). The films were also used to simultaneously measure the dose enhancement and beam attenuation through solutions containing 0%, 5% and 10% iodine (w/v). These depth-dose measurements were made in phantoms representing 3 cm targets located 0 and 4.8 cm deep in acrylic. Higher concentrations of contrast yielded greater dose enhancement and target-to-surface dose ratios, but caused more rapid attenuation of the beam as it traversed the target. The dose distribution across the entire target could be improved by employing multiple beams. These results, using concentrations of contrast that are clinically achievable by intratumoural injection, illustrate the potential of CERT for the specific delivery of high doses of radiation to targets at depth

  16. Safety Improvement in Radiotherapy Treatment Plan. Planning vs Redundant Check vs in vivo Dosimetry

    International Nuclear Information System (INIS)

    Torres Diaz, J.; Ascencion Ybarra, Y.; La Fuentes Rosales, L. de; Lara Mas, E.; Larrinaga Cortinas, E.

    2013-01-01

    In Cuba it is mandatory to have an independent monitor units check before any radiotherapy treatment is started. The main objective of this paper is to enhance the safety of the radiotherapy planning by developing and testing a practical tool to double check the monitor units calculation for external beam high energy photon therapy. A software for monitor units (MUs) verification was designed and coded. It considers the common in clinical practice isocentric set-ups. The in vivo dosimetry measurements were done with a silicon diode system for 6 MV photon beams to support the validation of the software. The results show a discrepancy within 5% between the 3 methods which is in accordance with international recommendations. (Author)

  17. Guidelines for the preparation of a quality manual for external audit groups on dosimetry in radiotherapy

    International Nuclear Information System (INIS)

    Izewska, Joanna; Arib, M.; Saravi, M.

    2002-01-01

    This document has been prepared within the framework of a Co-ordinated Research Programme (CRP) on Development of Quality Assurance Programme for Radiation Therapy Dosimetry in Developing Countries, during two Meetings at the IAEA Headquarters in Vienna (11-14 November 1996 and 6-10 October 1997). It is based on the recommendations of ISO 9000 series and ISO/IEC guide No. 25. The document can be used as a guide on how to prepare a quality manual for national External Audit Groups (EAG), i.e., a nationally recognised group in charge of operating external quality audits for radiotherapy dosimetry. The EAG of a given country includes the SSDL, a Measuring Group and a Medical Physics Group, who work in close co-operation at all steps of the audit. The content herein should be considered as a suggestion and additions or deletions can be made in accordance with the specific conditions in each country. It is preferable that the manual itself be as concise as possible, limiting it to the core scope. Detailed working sheets describing the procedures should be included in Appendices together with data sheets, questionnaires and reporting forms. The quality manual of each country should be carefully reviewed by all members of the EAG and, as far as possible, should be approved by relevant professional bodies and supported by health authorities. It has long been recognised that accurate knowledge of the dose in radiotherapy is vital to ensure safe and effective radiation treatments. To achieve this goal, comprehensive quality assurance programmes should be established to cover all steps from dose prescription to dose delivery. These programmes should include internal checks performed by the radiotherapy centres and external audits made by independent external bodies. It is estimated that not more than 50% of radiotherapy facilities world-wide have participated in some level of dose quality audit by an independent expert. Genuine concern exists that some, or even many

  18. Quality control of the treatment planning systems dose calculations in external radiation therapy using the Penelope Monte Carlo code; Controle qualite des systemes de planification dosimetrique des traitements en radiotherapie externe au moyen du code Monte-Carlo Penelope

    Energy Technology Data Exchange (ETDEWEB)

    Blazy-Aubignac, L

    2007-09-15

    The treatment planning systems (T.P.S.) occupy a key position in the radiotherapy service: they realize the projected calculation of the dose distribution and the treatment duration. Traditionally, the quality control of the calculated distribution doses relies on their comparisons with dose distributions measured under the device of treatment. This thesis proposes to substitute these dosimetry measures to the profile of reference dosimetry calculations got by the Penelope Monte-Carlo code. The Monte-Carlo simulations give a broad choice of test configurations and allow to envisage a quality control of dosimetry aspects of T.P.S. without monopolizing the treatment devices. This quality control, based on the Monte-Carlo simulations has been tested on a clinical T.P.S. and has allowed to simplify the quality procedures of the T.P.S.. This quality control, in depth, more precise and simpler to implement could be generalized to every center of radiotherapy. (N.C.)

  19. Dosimetry in radiotherapy and brachytherapy by Monte-Carlo GATE simulation on computing grid; Dosimetrie en radiotherapie et curietherapie par simulation Monte-Carlo GATE sur grille informatique

    Energy Technology Data Exchange (ETDEWEB)

    Thiam, Ch.O

    2007-10-15

    Accurate radiotherapy treatment requires the delivery of a precise dose to the tumour volume and a good knowledge of the dose deposit to the neighbouring zones. Computation of the treatments is usually carried out by a Treatment Planning System (T.P.S.) which needs to be precise and fast. The G.A.T.E. platform for Monte-Carlo simulation based on G.E.A.N.T.4 is an emerging tool for nuclear medicine application that provides functionalities for fast and reliable dosimetric calculations. In this thesis, we studied in parallel a validation of the G.A.T.E. platform for the modelling of electrons and photons low energy sources and the optimized use of grid infrastructures to reduce simulations computing time. G.A.T.E. was validated for the dose calculation of point kernels for mono-energetic electrons and compared with the results of other Monte-Carlo studies. A detailed study was made on the energy deposit during electrons transport in G.E.A.N.T.4. In order to validate G.A.T.E. for very low energy photons (<35 keV), three models of radioactive sources used in brachytherapy and containing iodine 125 (2301 of Best Medical International; Symmetra of Uro- Med/Bebig and 6711 of Amersham) were simulated. Our results were analyzed according to the recommendations of task group No43 of American Association of Physicists in Medicine (A.A.P.M.). They show a good agreement between G.A.T.E., the reference studies and A.A.P.M. recommended values. The use of Monte-Carlo simulations for a better definition of the dose deposited in the tumour volumes requires long computing time. In order to reduce it, we exploited E.G.E.E. grid infrastructure where simulations are distributed using innovative technologies taking into account the grid status. Time necessary for the computing of a radiotherapy planning simulation using electrons was reduced by a factor 30. A Web platform based on G.E.N.I.U.S. portal was developed to make easily available all the methods to submit and manage G

  20. 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

  1. The role of the National Physical Laboratory in monitoring and improving dosimetry in UK radiotherapy

    International Nuclear Information System (INIS)

    Thomas, R.A.S.; Duane, S.; McEwen, M.R.; Rosser, K.E.

    2002-01-01

    In the UK, the National Physical Laboratory, in collaboration with the Institute for Physics and Engineering in Medicine operates an audit programme to ensure national consistency in radiotherapy dosimetry. The present programme covers dosimetry of megavoltage photons and electrons (3-19 MeV) and low and medium energy (10-300 kV) photons. The aim of each audit is to verify the local measurement of absorbed dose at the radiotherapy centre. The audit measurements - principally beam quality and linac output - are made following the same protocol as the clinic but using different equipment. The audit is not an absolute measurement of the absorbed dose but amounts to a check that the equipment used by the centre is operating as expected and that the Code of Practice is being followed correctly. The protocols used in the UK are IPSM 1990 for high-energy photons, IPEMB 1996 for electrons and IPEMB 1996 for low energy photons. For the purpose of these audits, NPL maintains a set of calibrated ionisation chambers

  2. Phantom dosimetry for conformal stereotactic radiotherapy with a Head and Neck Localizer frame

    Energy Technology Data Exchange (ETDEWEB)

    Ravindran, B. Paul [Department of Radiation Oncology, Christian Medical College Hospital, Vellore (India)]. E-mail: paul@cmcvellore.ac.in; Fairclough, Lee [Department of Radiation Therapy, Princess Margaret Hospital, Toronto (Canada); Jaywant, Satish M. [Department of Clinical Physics, Princess Margaret Hospital, Toronto (Canada)

    2001-07-01

    Linear accelerator based stereotactic radiotherapy (SRT) with the Gill-Thomas-Cosman (GTC) re-locatable frame has been in use for several years. The use of the frame is limited to treating lesions above the hard palate. For treating tumours in the head and neck region, the Head and Neck Localizer (HNL) frame has been designed by Radionics Inc. for use with their XPlan treatment planning software. In this study we have used a spherical acrylic phantom commercially known as the 'Lucy' phantom (Sandstrom Sandstrom Trade and Technology Inc.) to perform thermoluminiscent as well as film dosimetry for the HNL frame. A radio-opaque marker was placed in the phantom and a film test carried out to verify the accuracy in isocentre positioning. The results of the dosimetry with TLD were within 2% for points near the isocentre and 5% (or 2 mm in steep gradients) in the planning target volume (PTV). In regions of low dose, larger percentage differences in local dose were observed, but all differences were within 5% of isocentre dose. The film dosimetry provided dose distributions that matched well with those generated by the XPlan stereotactic treatment planning software. (author)

  3. Dosimetric inter-institutional comparison in European radiotherapy centres: Results of IAEA supported treatment planning system audit.

    Science.gov (United States)

    Gershkevitsh, Eduard; Pesznyak, Csilla; Petrovic, Borislava; Grezdo, Joseph; Chelminski, Krzysztof; do Carmo Lopes, Maria; Izewska, Joanna; Van Dyk, Jacob

    2014-05-01

    One of the newer audit modalities operated by the International Atomic Energy Agency (IAEA) involves audits of treatment planning systems (TPS) in radiotherapy. The main focus of the audit is the dosimetry verification of the delivery of a radiation treatment plan for three-dimensional (3D) conformal radiotherapy using high energy photon beams. The audit has been carried out in eight European countries - Estonia, Hungary, Latvia, Lithuania, Serbia, Slovakia, Poland and Portugal. The corresponding results are presented. The TPS audit reviews the dosimetry, treatment planning and radiotherapy delivery processes using the 'end-to-end' approach, i.e. following the pathway similar to that of the patient, through imaging, treatment planning and dose delivery. The audit is implemented at the national level with IAEA assistance. The national counterparts conduct the TPS audit at local radiotherapy centres through on-site visits. TPS calculated doses are compared with ion chamber measurements performed in an anthropomorphic phantom for eight test cases per algorithm/beam. A set of pre-defined agreement criteria is used to analyse the performance of TPSs. TPS audit was carried out in 60 radiotherapy centres. In total, 190 data sets (combination of algorithm and beam quality) have been collected and reviewed. Dosimetry problems requiring interventions were discovered in about 10% of datasets. In addition, suboptimal beam modelling in TPSs was discovered in a number of cases. The TPS audit project using the IAEA methodology has verified the treatment planning system calculations for 3D conformal radiotherapy in a group of radiotherapy centres in Europe. It contributed to achieving better understanding of the performance of TPSs and helped to resolve issues related to imaging, dosimetry and treatment planning.

  4. Verification of radiotherapy doses by EPR dosimetry in patients' teeth

    International Nuclear Information System (INIS)

    Kaminska, J.; Ciesielski, B.; Drogoszewska, B.; Emerich, K.; Krefft, K.; Juniewicz, M.

    2016-01-01

    The aim of this work was to verify applicability of electron paramagnetic resonance (EPR) ex vivo dosimetry in teeth enamel for determination of doses absorbed by patients during radiotherapy with radiation fields covering head regions and to examine with what accuracy the doses predicted by radiotherapy treatment plan (RTP) can be confirmed by doses measured ex post by the EPR method. The doses were determined in 22 enamel samples obtained from 11 patients who, after their radiotherapy treatment underwent extraction of teeth due to medical reasons. The delivered doses were determined by measuring EPR signals in enamel samples from the extracted teeth; magnitude of these signals is proportional to concentration of stable free radicals induced by radiation in the hydroxyapatite content of enamel. The measured doses were compared with doses planned in the teeth locations by RTP systems. The relation between the measured (D m ) and the planned (D p ) doses can be described as a linear function: D m  = s·D p  + b, with the slope s = 0.93 ± 0.03 and the intercept b = 0.67 ± 1.26. The deviations between the measured and calculated doses were in the (−12.6%, +1.9%) range with the average deviation of – 4.6%. It is concluded, than more accurate measurements, achievable when using a higher calibration dose than in the present study, are necessary to confirm or to deny the observed bias between the measured and planned doses. - Highlights: • EPR signal in enamel is proportional to dose delivered in vivo during radiotherapy. • The average deviation of the measured from the planned doses was −4.6%. • The doses in enamel can be determined many years after radiotherapy.

  5. Development of DosiMap: dosimetry device for radiotherapy quality assurance; Developpement du DosiMap: instrument de dosimetrie pour le controle qualite en radiotherapie

    Energy Technology Data Exchange (ETDEWEB)

    Frelin, A.M

    2006-10-15

    This thesis deals with the development of a new dosimetry device for the control of radiotherapy beams. This device is composed of a plane plastic scintillator which is set within a polystyrene phantom. When the 'DosiMap' is irradiated, light is produced. This light is composed of scintillation and Cerenkov radiation, and is accurately measured by a C.C.D. camera. The analysis of the light distribution enables us to deduce the dose distribution in the scintillator plan. This device has many advantages such as tissue equivalence, a good spatial resolution, and a linear response with regard to energy. It also provides immediate measurements, and as a consequence, it is a very adapted tool for clinical use. After the introduction about the basic notions of radiotherapy, the different steps of the 'DosiMap' development are exposed in this thesis. In a first time, plastic scintillators have been tested to determine the best one for this application. Then, the deconvolution of scintillation and Cerenkov radiation have been studied, because we only use scintillation to calculate the dose distribution. The camera being in the irradiation room, a lead shield has also been developed to protect the C.C.D. detector from scattered radiations. Finally, the dose calibration and the dose response of 'DosiMap' are exposed. All this work made feasible the measurement of dose distributions with a precision which turns out to be better than 2% for homogeneous photon beams. Excellent results were also obtained when modulated intensity beams are used. (author)

  6. 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)

  7. 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

  8. Thermoluminescent (Tl) dosimetry of slow-neutron fields at radiotherapy dose level

    International Nuclear Information System (INIS)

    Gambarini, G.

    2003-01-01

    The dosimetry for radiotherapy involving neutrons is very complicated, owing to the complexity of secondary radiation components, whose contributions to the total absorbed dose have to be discriminated, owing to the different radiobiological effects. In order to separate thermal neutrons and photons, LiF dosimeters are mostly utilized. containing different percentage of Li, like as TLD-700, TLD-100 and TLD-600, but many problems arise. In the response of TLD-700 exposed to neutron-gamma mixed fields with high neutron flux, the contribution of thermal neutrons to the Tl emission is high. Moreover. TLD-100 and TLD-600 may undergo radiation damage, and great care has to be taken in order to obtain reliable results. Other TLDs showing lower sensitivity to neutrons are proposed and experimented for such high-flux neutron fields. The faced problems and various proposed solutions are here described. (Author)

  9. A TPS kernel for calculating survival vs. depth: distributions in a carbon radiotherapy beam, based on Katz's cellular Track Structure Theory.

    Science.gov (United States)

    Waligórski, M P R; Grzanka, L; Korcyl, M; Olko, P

    2015-09-01

    An algorithm was developed of a treatment planning system (TPS) kernel for carbon radiotherapy in which Katz's Track Structure Theory of cellular survival (TST) is applied as its radiobiology component. The physical beam model is based on available tabularised data, prepared by Monte Carlo simulations of a set of pristine carbon beams of different input energies. An optimisation tool developed for this purpose is used to find the composition of pristine carbon beams of input energies and fluences which delivers a pre-selected depth-dose distribution profile over the spread-out Bragg peak (SOBP) region. Using an extrapolation algorithm, energy-fluence spectra of the primary carbon ions and of all their secondary fragments are obtained over regular steps of beam depths. To obtain survival vs. depth distributions, the TST calculation is applied to the energy-fluence spectra of the mixed field of primary ions and of their secondary products at the given beam depths. Katz's TST offers a unique analytical and quantitative prediction of cell survival in such mixed ion fields. By optimising the pristine beam composition to a published depth-dose profile over the SOBP region of a carbon beam and using TST model parameters representing the survival of CHO (Chinese Hamster Ovary) cells in vitro, it was possible to satisfactorily reproduce a published data set of CHO cell survival vs. depth measurements after carbon ion irradiation. The authors also show by a TST calculation that 'biological dose' is neither linear nor additive. © The Author 2015. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  10. A TPS kernel for calculating survival vs. depth: distributions in a carbon radiotherapy beam, based on Katz's cellular track structure theory

    International Nuclear Information System (INIS)

    Waligorski, M.P.R.; Grzanka, L.; Korcyl, M.; Olko, P.

    2015-01-01

    An algorithm was developed of a treatment planning system (TPS) kernel for carbon radiotherapy in which Katz's Track Structure Theory of cellular survival (TST) is applied as its radiobiology component. The physical beam model is based on available tabularised data, prepared by Monte Carlo simulations of a set of pristine carbon beams of different input energies. An optimisation tool developed for this purpose is used to find the composition of pristine carbon beams of input energies and fluences which delivers a pre-selected depth-dose distribution profile over the spread-out Bragg peak (SOBP) region. Using an extrapolation algorithm, energy-fluence spectra of the primary carbon ions and of all their secondary fragments are obtained over regular steps of beam depths. To obtain survival vs. depth distributions, the TST calculation is applied to the energy-fluence spectra of the mixed field of primary ions and of their secondary products at the given beam depths. Katz's TST offers a unique analytical and quantitative prediction of cell survival in such mixed ion fields. By optimising the pristine beam composition to a published depth-dose profile over the SOBP region of a carbon beam and using TST model parameters representing the survival of CHO (Chinese Hamster Ovary) cells in vitro, it was possible to satisfactorily reproduce a published data set of CHO cell survival vs. depth measurements after carbon ion irradiation. The authors also show by a TST calculation that 'biological dose' is neither linear nor additive. (authors)

  11. Reshaping of computational system for dosimetry in neutron and photons radiotherapy based in stochastic methods - SISCODES

    International Nuclear Information System (INIS)

    Trindade, Bruno Machado

    2011-02-01

    This work shows the remodeling of the Computer System for Dosimetry of Neutrons and Photons in Radiotherapy Based on Stochastic Methods . SISCODES. The initial description and status, the alterations and expansions (proposed and concluded), and the latest system development status are shown. The SISCODES is a system that allows the execution of a 3D computational planning in radiation therapy, based on MCNP5 nuclear particle transport code. The SISCODES provides tools to build a patient's voxels model, to define a treatment planning, to simulate this planning, and to view the results of the simulation. The SISCODES implements a database of tissues, sources and nuclear data and an interface to access then. The graphical SISCODES modules were rewritten or were implemented using C++ language and GTKmm library. Studies about dose deviations were performed simulating a homogeneous water phantom as analogue of the human body in radiotherapy planning and a heterogeneous voxel phantom, pointing out possible dose miscalculations. The Soft-RT and PROPLAN computer codes that do interface with SISCODES are described. A set of voxels models created on the SISCODES are presented with its respective sizes and resolutions. To demonstrate the use of SISCODES, examples of radiation therapy and dosimetry simulations for prostate and heart are shown. Three protocols were simulated on the heart voxel model: Sm-153 filled balloon and P-32 stent, to prevent angioplasty restenosis; and Tl-201 myocardial perfusion, to imaging. Teletherapy with 6MV and 15MV beams were simulated to the prostate, and brachytherapy with I-125 seeds. The results of these simulations are shown on isodose curves and on dose-volume histograms. The SISCODES shows to be a useful tool for research of new radiation therapy treatments and, in future, can also be useful in medical practice. At the end, future improvements are proposed. I hope this work can contribute to develop more effective radiation therapy

  12. 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

  13. The evidence base for the use of internal dosimetry in the clinical practice of molecular radiotherapy

    Energy Technology Data Exchange (ETDEWEB)

    Strigari, Lidia [Regina Elena National Cancer Institute, Laboratory of Medical Physics and Expert Systems, Rome (Italy); Konijnenberg, Mark [Erasmus MC, Department of Nuclear Medicine, Rotterdam (Netherlands); Chiesa, Carlo [Instituto Nazionale Tumori, Department of Nuclear Medicine, Milan (Italy); Bardies, Manuel [UMR 1037 INSERM / Universite Paul Sabatier, Centre de Recherche en Cancerologie de Toulouse, Toulouse (France); Du, Yong [Royal Marsden NHS Foundation Trust, Department of Nuclear Medicine and PET/CT, Sutton, London (United Kingdom); Gleisner, Katarina Sjoegreen [Medical Radiation Physics, Clinical Sciences, Lund (Sweden); Lassmann, Michael [University of Wuerzburg, Department of Nuclear Medicine, Wuerzburg (Germany); Flux, Glenn [Royal Marsden NHS Foundation Trust and Institute of Cancer Research, Joint Department of Physics, Sutton (United Kingdom)

    2014-10-15

    Molecular radiotherapy (MRT) has demonstrated unique therapeutic advantages in the treatment of an increasing number of cancers. As with other treatment modalities, there is related toxicity to a number of organs at risk. Despite the large number of clinical trials over the past several decades, considerable uncertainties still remain regarding the optimization of this therapeutic approach and one of the vital issues to be answered is whether an absorbed radiation dose-response exists that could be used to guide personalized treatment. There are only limited and sporadic data investigating MRT dosimetry. The determination of dose-effect relationships for MRT has yet to be the explicit aim of a clinical trial. The aim of this article was to collate and discuss the available evidence for an absorbed radiation dose-effect relationships in MRT through a review of published data. Based on a PubMed search, 92 papers were found. Out of 79 studies investigating dosimetry, an absorbed dose-effect correlation was found in 48. The application of radiobiological modelling to clinical data is of increasing importance and the limited published data on absorbed dose-effect relationships based on these models are also reviewed. Based on National Cancer Institute guideline definition, the studies had a moderate or low rate of clinical relevance due to the limited number of studies investigating overall survival and absorbed dose. Nevertheless, the evidence strongly implies a correlation between the absorbed doses delivered and the response and toxicity, indicating that dosimetry-based personalized treatments would improve outcome and increase survival. (orig.)

  14. Effect of contrast agent administration on consequences of dosimetry and biology in radiotherapy planning

    Energy Technology Data Exchange (ETDEWEB)

    Lo, Ching-Jung [Department of Medical Imaging and Radiological Sciences, College of Medicine, Chang Gung University, 259 Wen-Hua 1st Road, Kwei-Shan, Tao-Yuan 333 Taiwan (China); Department of Radiation Oncology, Chang Gung Memorial Hospital, Kwei-Shan, Tao-Yuan 333 Taiwan (China); Yang, Pei-Ying [Department of Medical Imaging and Radiological Sciences, College of Medicine, Chang Gung University, 259 Wen-Hua 1st Road, Kwei-Shan, Tao-Yuan 333 Taiwan (China); Chao, Tsi-Chian, E-mail: chaot@mail.cgu.edu.tw [Department of Medical Imaging and Radiological Sciences, College of Medicine, Chang Gung University, 259 Wen-Hua 1st Road, Kwei-Shan, Tao-Yuan 333 Taiwan (China); Tu, Shu-Ju, E-mail: sjtu@mail.cgu.edu.tw [Department of Medical Imaging and Radiological Sciences, College of Medicine, Chang Gung University, 259 Wen-Hua 1st Road, Kwei-Shan, Tao-Yuan 333 Taiwan (China)

    2015-06-01

    In the treatment planning of radiation therapy, patients may be administrated with contrast media in CT scanning to assist physicians for accurate delineation of the target or organs. However, contrast media are not used in patients during the treatment delivery. In particular, contrast media contain materials with high atomic numbers and dosimetric variations may occur between scenarios where contrast media are present in treatment planning and absent in treatment delivery. In this study we evaluate the effect of contrast media on the dosimetry and biological consequence. An analytical phantom based on AAPM TG 119 and five sets of CT images from clinical patients are included. Different techniques of treatment planning are considered, including 1-field AP, 2-field AP+PA, 4-field box, 7-field IMRT, and RapidArc. RapidArc is a recent technique of volumetric modulated arc therapy and is used in our study of contrast media in clinical scenarios. The effect of RapidArc on dosimetry and biological consequence for administration of contrast media in radiotherapy is not discussed previously in literature. It is shown that dose difference is reduced as the number of external beams is increased, suggesting RapidArc may be favored to be used in the treatment planning enhanced by contrast media. Linear trend lines are fitted for assessment of percent dose differences in the planning target volume versus concentrations of contrast media between plans where contrast media are present and absent, respectively.

  15. Study of film dosimetry for radiotherapy with Gafchromic-RTQ plates

    International Nuclear Information System (INIS)

    Diaz Moreno, Rogelio Manuel; Lara Mas, Elier; Alfonso Laguardia, Rodolfo

    2009-01-01

    Film dosimetry allows quality control processes (CC) for advanced radiotherapy treatments, not achievable with other types of systems dosimetry, as is the determination of two-dimensional dose distribution provided with the planned treatment in selected planes. The aim of this work was to establish the possibilities of making this type of CC with the means available in the INOR. Plates were used radiochromic Gafchromic-RTQ, for quality control, which irradiated with Elekta Precise linear accelerator, according to the test planning developed in the treatment planning system Precise Plan. Were used as image processing software the Mephysto mc2, PTW, and routines scheduled at home on Matlab. Was prepared calibration curve Dose-response for these plates, and applied this calibration curve at other boards with known radiation dose to estimate proximity of the dose obtained through calibration. Other tests were performed to determine the conditions of repeatability and optimal parameters of the process. Conditions were established that are obtained more reliable , the which are lower than those reported Gafchromic-EBT plates, especially designed quantitative dosimetric purposes, but in certain ranges allow evaluate the of a plan with an acceptable degree of approximation. (author)

  16. The New Zealand audit of radiotherapy dosimetry: Practical considerations and results

    International Nuclear Information System (INIS)

    Smyth, V.G.; Laban, J.A.

    2002-01-01

    The New Zealand Radiation Protection Regulations 1982 state that the dose delivered to a radiotherapy patient must be within ±5% of the prescribed dose. Following the overdose of 153 patients because of an error in dosimetry at Royal Devon and Exeter Hospital, UK, in 1988 it was decided to audit compliance with this routinely. Since 1991 every high-energy beam in NZ used for teletherapy has been independently measured every two years by staff from NRL. Since 1997 all kV x-ray beams have been measured as well. The measurements follow the dosimetry protocol TRS-277. A Sr-90 check is taken at each site to verify stability of the measurement system. Agreement within 0.5% is accepted. The SSD on a linear accelerator is set using the optical distance indicator after checking it against a mechanical front pointer. Recombination corrections are measured on each linear accelerator beam and polarity corrections as well in the case of electron beams. The results for high-energy beams have been reassuring both to the regulators and to the physicists who appreciate the independent check. The only disagreements significantly greater than 2% have caused by the use of a cylindrical chamber on a 4MV electron beam by a hospital, and confusion between SSD and isocentric set-up. When we repeated the measurement using the same set-up as the hospital the difference was resolved

  17. Development of a calibration protocol for quantitative imaging for molecular radiotherapy dosimetry

    Science.gov (United States)

    Wevrett, J.; Fenwick, A.; Scuffham, J.; Nisbet, A.

    2017-11-01

    Within the field of molecular radiotherapy, there is a significant need for standardisation in dosimetry, in both quantitative imaging and dosimetry calculations. Currently, there are a wide range of techniques used by different clinical centres and as a result there is no means to compare patient doses between centres. To help address this need, a 3 year project was funded by the European Metrology Research Programme, and a number of clinical centres were involved in the project. One of the required outcomes of the project was to develop a calibration protocol for three dimensional quantitative imaging of volumes of interest. Two radionuclides were selected as being of particular interest: iodine-131 (131I, used to treat thyroid disorders) and lutetium-177 (177Lu, used to treat neuroendocrine tumours). A small volume of activity within a scatter medium (water), representing a lesion within a patient body, was chosen as the calibration method. To ensure ease of use in clinical centres, an "off-the-shelf" solution was proposed - to avoid the need for in-house manufacturing. The BIODEX elliptical Jaszczak phantom and 16 ml fillable sphere were selected. The protocol was developed for use on SPECT/CT gamma cameras only, where the CT dataset would be used to correct the imaging data for attenuation of the emitted photons within the phantom. The protocol corrects for scatter of emitted photons using the triple energy window correction technique utilised by most clinical systems. A number of clinical systems were tested in the development of this protocol, covering the major manufacturers of gamma camera generally used in Europe. Initial imaging was performed with 131I and 177Lu at a number of clinical centres, but due to time constraints in the project, some acquisitions were performed with 177Lu only. The protocol is relatively simplistic, and does not account for the effects of dead-time in high activity patients, the presence of background activity surrounding

  18. Metrological legal frame in the field of the photon dosimetry of radiotherapy in Cuba

    International Nuclear Information System (INIS)

    Walwyn S, G.; Gutierrez L, S.; Gonzalez R, N.

    2006-01-01

    The Clinical Dosimetry in the planning of the doses to administer to patients under radiant treatment is of great importance. At the moment the clinical dosemeters its are manufactured with a high technology but errors of production or manipulation cannot be discarded that lead to errors in this planning. It also exists, a group of metrological and of operation parameters that are not checked in a routine calibration, and for those that are checked, legal base that restricts its use in cases of bad operation doesn't exist. This motivated to the Cuban standard elaboration NC 352:2005, for the verification of reference dosemeters of radiotherapy, process that trafficked for an exhaustive search and study of standards and international technical reports, selecting as base document, the standard IEC 60731:1997, for essays of approval of model of clinical dosemeters used in radiotherapy. The present article shows the main technical aspects considered and the requirements and verification methods for the declaration of aptitude of the dosemeters. This document constitutes the scientific base for the implementation from a verification service to national level and an important contribution to the standardization of the metrology of ionizing radiations of Cuba. (Author)

  19. Quality audit of radiotherapy with EORTC mailed in water TL-dosimetry

    Energy Technology Data Exchange (ETDEWEB)

    Hansson, U.; Johansson, K.-A. (Goeteborg Univ. (Sweden). Dept. of Radiation Physics Sahlgrenska Sjukhuset, Goeteborg (Sweden))

    1991-03-01

    A mailable TL-dosimetry (LiF) system has been designed and tested for the EORTC Radiotherapy Group for periodic monitoring of radiation therapy machines between and prior to on-site visits. 3 TL-dosimeters were enclosed in a capsule which was placed in a holder and irradiated in photon beams in a water phantom. The institutes were instructed to irradiate the capsule to an absorbed dose of 2 Gy. After the irradiation, all capsules with dosimeter, the holder and completed data sheets were returned to Gothenburg for evaluation. The heating procedure used for reading the dosimeters was optimised regarding fading and reproducibility (<0.5 percent, 1. S.D.). The fading of the TL-signal was eliminated by adding an external annealing to the heating procedure. Both supralinearity and energy dependence were tested and routinely corrected for. The dosimeters were individually calibrated. During 1987, 1988 and the 1st part of 1989, dosimeters were mailed to 22 institutes, participating in clinical trials organised by the Radiotherapy Group. Of the 178 beams measured, 89 percent were within acceptable level;s of variation for the absorbed dose states (<=4 percent). The photon results gave a mean of 1.012 and a standard deviation of 0.025. (author). 6 refs.; 4 figs.; 3 tabs.

  20. As the thermoluminescent dosimetry can help in the quality control in radiotherapy

    International Nuclear Information System (INIS)

    Araujo, Anna Maria Campos de; Marin, Alfredo Viamonte; Viegas, Claudio C.B.; Souza, Roberto Salomon de; Alves, Victor Gabriel Leandro

    2011-01-01

    According to the international (International Atomic Energy Agency) and national (Agencia Nacional de Vigilancia Sanitaria- ANVISA) rules, the irradiators of any radiotherapy department should be periodical/y checked through a quality control external audit. In Brazil, where we have about 300 radiotherapy equipment, is very difficult to perform these audits on site with a acceptable frequency. For this reason, the Quality Service on Ionizing Radiations from the National Cancer Institute-INCA/Rio de Janeiro, developed and implemented postal systems to evaluate the main parameters of the radiotherapeutic equipment (Co-60, linear accelerators and high dose rate brachytherapy). All the postal systems developed are based on thermoluminescent dosimeters. The aim of this paper is to share the INCA experience in the use of TLD for dose evaluation and quality control measurements. Following the same philosophy, INCA developed also a postal system to evaluate the doses in mammography, since Brazil has 4000 equipment and performs about 8 millions of mammograms per year. A new experience is studying the OSL dosimeters to be used also for dose evaluation, including for in vivo dosimetry. (author)

  1. Development of dose audits for complex treatment techniques in radiotherapy

    International Nuclear Information System (INIS)

    Stefanic, A. M.; Molina, L.; Vallejos, M.; Montano, G.; Zaretzky, A.; Saravi, M.

    2014-08-01

    This work was performed in the frame of a Coordinated Research Project (CRP) with IAEA whose objective was to extend the scope of activities carried out by national TLD-based networks from dosimetry audit for rectangular radiation fields to irregular and small fields relevant to modern radiotherapy. External audit is a crucial element in QA programmes for clinical dosimetry in radiotherapy, therefore a methodology and procedures were developed and were made available for dose measurement of complex radiotherapy parameters used for cancer treatment. There were three audit steps involved in this CRP: TLD based dosimetry for irregular MLC fields for conformal radiotherapy, dosimetry in the presence of heterogeneities and 2D MLC shaped fields relevant to stereotactic radiotherapy and applicable to dosimetry for IMRT. In addition, a new development of film-based 2D dosimetry for testing dose distributions in small field geometry was included. The plan for each audit step involved a pilot study and a trial audit run with a few local hospitals. The pilot study focused on conducting and evaluation of the audit procedures with all participants. The trial audit run was the running of the audit procedures by the participants to test them with a few local radiotherapy hospitals. This work intends to provide audits which are much nearer clinical practice than previous audits as they involve significant testing of Tps methods, as well as verifications to determinate whether hospitals can correctly calculate dose delivery in radiation treatments. (author)

  2. Development of dose audits for complex treatment techniques in radiotherapy

    Energy Technology Data Exchange (ETDEWEB)

    Stefanic, A. M.; Molina, L.; Vallejos, M.; Montano, G.; Zaretzky, A.; Saravi, M., E-mail: stefanic@cae.cnea.gov.ar [Centro Regional de Referencia con Patrones Secundarios para Dosimetria - CNEA, Presbitero Juan Gonzalez y Aragon 15, B1802AYA Ezeiza (Argentina)

    2014-08-15

    This work was performed in the frame of a Coordinated Research Project (CRP) with IAEA whose objective was to extend the scope of activities carried out by national TLD-based networks from dosimetry audit for rectangular radiation fields to irregular and small fields relevant to modern radiotherapy. External audit is a crucial element in QA programmes for clinical dosimetry in radiotherapy, therefore a methodology and procedures were developed and were made available for dose measurement of complex radiotherapy parameters used for cancer treatment. There were three audit steps involved in this CRP: TLD based dosimetry for irregular MLC fields for conformal radiotherapy, dosimetry in the presence of heterogeneities and 2D MLC shaped fields relevant to stereotactic radiotherapy and applicable to dosimetry for IMRT. In addition, a new development of film-based 2D dosimetry for testing dose distributions in small field geometry was included. The plan for each audit step involved a pilot study and a trial audit run with a few local hospitals. The pilot study focused on conducting and evaluation of the audit procedures with all participants. The trial audit run was the running of the audit procedures by the participants to test them with a few local radiotherapy hospitals. This work intends to provide audits which are much nearer clinical practice than previous audits as they involve significant testing of Tps methods, as well as verifications to determinate whether hospitals can correctly calculate dose delivery in radiation treatments. (author)

  3. Recommendations for the commissioning and use of a radiotherapy treatment planning system (TPS). S.F.P.M. report nr 27, December 1, 2010

    International Nuclear Information System (INIS)

    Rosenwald, Jean Claude; Bonvalet, Laurent; Mazurier, Jocelyne; Metayer, Christine; Beaudre, Anne; Garcia, Robin; Ruchaud, Romain; Dedieu, Veronique; Bramoulle, Celine; Caselles, Olivier; Lacaze, Brigitte; Mazurier, Jocelyne

    2010-01-01

    This report aims at bringing risks related to the use of Treatment Planning Systems (TPS) to the attention of French medical physicists, and to provide them with practical, precise and updated recommendations related to new legal requirements on commissioning and use of a new planning system. It addresses TPS used in external radiation therapy. It is based on various international (IAEA, ESTRO, AAPM, and so on) and national recommendations, and proposes some rules of good practices for the implementation of a quality insurance policy as well as for the procurement and implementation of a new planning system, as for the performance follow-up of an already installed system. The authors address the following issues: risks associated with the use of a TPS, organisational aspects, dose calculation algorithms and required precision, TPS acceptance, adjustment and tests, periodic controls, treatment plan verification procedures

  4. Dosimetry in radiotherapy and brachytherapy by Monte-Carlo GATE simulation on computing grid

    International Nuclear Information System (INIS)

    Thiam, Ch.O.

    2007-10-01

    Accurate radiotherapy treatment requires the delivery of a precise dose to the tumour volume and a good knowledge of the dose deposit to the neighbouring zones. Computation of the treatments is usually carried out by a Treatment Planning System (T.P.S.) which needs to be precise and fast. The G.A.T.E. platform for Monte-Carlo simulation based on G.E.A.N.T.4 is an emerging tool for nuclear medicine application that provides functionalities for fast and reliable dosimetric calculations. In this thesis, we studied in parallel a validation of the G.A.T.E. platform for the modelling of electrons and photons low energy sources and the optimized use of grid infrastructures to reduce simulations computing time. G.A.T.E. was validated for the dose calculation of point kernels for mono-energetic electrons and compared with the results of other Monte-Carlo studies. A detailed study was made on the energy deposit during electrons transport in G.E.A.N.T.4. In order to validate G.A.T.E. for very low energy photons (<35 keV), three models of radioactive sources used in brachytherapy and containing iodine 125 (2301 of Best Medical International; Symmetra of Uro- Med/Bebig and 6711 of Amersham) were simulated. Our results were analyzed according to the recommendations of task group No43 of American Association of Physicists in Medicine (A.A.P.M.). They show a good agreement between G.A.T.E., the reference studies and A.A.P.M. recommended values. The use of Monte-Carlo simulations for a better definition of the dose deposited in the tumour volumes requires long computing time. In order to reduce it, we exploited E.G.E.E. grid infrastructure where simulations are distributed using innovative technologies taking into account the grid status. Time necessary for the computing of a radiotherapy planning simulation using electrons was reduced by a factor 30. A Web platform based on G.E.N.I.U.S. portal was developed to make easily available all the methods to submit and manage G

  5. Real-time optical-fibre luminescence dosimetry for radiotherapy: physical characteristics and applications in photon beams

    DEFF Research Database (Denmark)

    Aznar, M.C.; Andersen, C.E.; Bøtter-Jensen, L.

    2004-01-01

    , real-time read-out and the ability to measure both dose rate and absorbed dose. The measurements describing reproducibility and output dependence on dose rate, field size and energy all had standard deviations smaller than 1%. The signal variation with the angle of incidence was smaller than 2% (1 SD......). Measurements performed in clinical situations suggest the potential of using this real-time system for in vivo dosimetry in radiotherapy....

  6. Dosimetry, clinical factors and medication intake influencing urinary symptoms after prostate radiotherapy: An analysis of data from the RADAR prostate radiotherapy trial

    International Nuclear Information System (INIS)

    Yahya, Noorazrul; Ebert, Martin A.; Bulsara, Max; Haworth, Annette; Kennedy, Angel; Joseph, David J.; Denham, Jim W.

    2015-01-01

    Purpose/objective: To identify dosimetry, clinical factors and medication intake impacting urinary symptoms after prostate radiotherapy. Material and methods: Data describing clinical factors and bladder dosimetry (reduced with principal component (PC) analysis) for 754 patients treated with external beam radiotherapy accrued by TROG 03.04 RADAR prostate radiotherapy trial were available for analysis. Urinary symptoms (frequency, incontinence, dysuria and haematuria) were prospectively assessed using LENT-SOMA to a median of 72 months. The endpoints assessed were prevalence (grade ⩾1) at the end of radiotherapy (representing acute symptoms), at 18-, 36- and 54-month follow-ups (representing late symptoms) and peak late incidence including only grade ⩾2. Impact of factors was assessed using multivariate logistic regression models with correction for over-optimism. Results: Baseline symptoms, non-insulin dependent diabetes mellitus, age and PC1 (correlated to the mean dose) impact symptoms at >1 timepoints. Associations at a single timepoint were found for cerebrovascular condition, ECOG status and non-steroidal anti-inflammatory drug intake. Peak incidence analysis shows the impact of baseline, bowel and cerebrovascular condition and smoking status. Conclusions: The prevalence and incidence analysis provide a complementary view for urinary symptom prediction. Sustained impacts across time points were found for several factors while some associations were not repeated at different time points suggesting poorer or transient impact

  7. SU-E-T-153: Detector-Grade CVD Diamond for Radiotherapy Dosimetry.

    Science.gov (United States)

    Lansley, S; Betzel, G; McKay, D; Meyer, J

    2012-06-01

    To evaluate the use of commercially available detector-grade synthetic diamond films made via chemical vapor deposition (CVD) as x- ray detectors for radiotherapy dosimetry. A detector was fabricated using high-quality single crystal CVD diamond films (0.5 × 3 × 3 mm̂3) with 0.4 mm̂3 sensitive volumes, which were encapsulated with PMMA. The detector was placed in a (30 × 30 × 30 cm̂3) PTW water phantom. Six- and ten-MV photons from an Elekta Synergy linac were measured using an SSD of 90 cm and typically a 10-cm phantom depth with a 10 × 10 cm̂2 field size in the central axis of the beam. Data acquisition was performed using a PTW UNIDOS E electrometer with a 100-V bias. The detector was evaluated by measuring leakage current, priming dose, response dynamics, dose linearity, dependence on dose rate, percent depth dose (6 and 10 MV photons) and output factors. Some measurements were compared with a Si diode detector, 0.04 and/or 0.13-cc ion chamber(s). Leakage currents were negligible (∼1 pA) given the overall average sensitivity of the material (680 nC/Gy at 100 V). Detector current rise and fall times were detectors as expected. The type of diamond tested has potential to be used for small field dosimetry due to its small sensitive volume and high sensitivity. Further experiments are ongoing and detector packaging is yet to be optimized. © 2012 American Association of Physicists in Medicine.

  8. In vivo dosimetry and acute toxicity in breast cancer patients undergoing intraoperative radiotherapy as boost

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Jason Joon Bock; Choi, Jin Hyun; Lee, Ik Jae; Park, Kwang Woo; Kim, Kang Pyo; Kim, Jun Won [Dept. of Radiation Oncology, Yonsei University College of Medicine, Seoul (Korea, Republic of); Ahn, Sung Gwe; Jeong, Joon [Dept. of Surgery, Gangnam Severance Hospital, Yonsei University College of Medicine, Seoul (Korea, Republic of)

    2017-06-15

    To report the results of a correlation analysis of skin dose assessed by in vivo dosimetry and the incidence of acute toxicity. This is a phase 2 trial evaluating the feasibility of intraoperative radiotherapy (IORT) as a boost for breast cancer patients. Eligible patients were treated with IORT of 20 Gy followed by whole breast irradiation (WBI) of 46 Gy. A total of 55 patients with a minimum follow-up of 1 month after WBI were evaluated. Optically stimulated luminescence dosimeter (OSLD) detected radiation dose delivered to the skin during IORT. Acute toxicity was recorded according to the Common Terminology Criteria for Adverse Events v4.0. Clinical parameters were correlated with seroma formation and maximum skin dose. Median follow-up after IORT was 25.9 weeks (range, 12.7 to 50.3 weeks). Prior to WBI, only one patient developed acute toxicity. Following WBI, 30 patients experienced grade 1 skin toxicity and three patients had grade 2 skin toxicity. Skin dose during IORT exceeded 5 Gy in two patients: with grade 2 complications around the surgical scar in one patient who received 8.42 Gy. Breast volume on preoperative images (p = 0.001), ratio of applicator diameter and breast volume (p = 0.002), and distance between skin and tumor (p = 0.003) showed significant correlations with maximum skin dose. IORT as a boost was well-tolerated among Korean women without severe acute complication. In vivo dosimetry with OSLD can help ensure safe delivery of IORT as a boost.

  9. SU-G-TeP2-06: Development of Novel Radiochromic Films for Radiotherapy Dosimetry

    Energy Technology Data Exchange (ETDEWEB)

    Alqathami, M; Lee, H; Ibbott, G [UT MD Anderson Cancer Center, Houston, TX (United States); Won Choi, G [UT MD Anderson Cancer Center, Houston, TX-Texas (United States); Blencowe, A [The University of South Australia, South Australia, SA (Australia); Wen, Z [MD Anderson Cancer Center, Houston, TX (United States); Adamovics, J [Department of Chemistry and Biology, Rider University, Skillman, NJ (United States)

    2016-06-15

    Purpose: To develop and evaluate novel radiochromic films for quality assurance in radiotherapy dosimetry. Materials and Methods: Novel radiochromic film compositions were formulated using leuco crystal violet (LCV) as a reporting system and tetrabromoethane as a free radical source. The film matrix used consisted of polyurethane polymer mixed with dibutyl phthalate plasticizer (20 wt%). The concentration of the radical initiator was kept constant at 10 wt% and the concentration of the LCV dye varied (1 and 2 wt%). To ensure uniform thickness of the film, its precursors were sandwiched between two pieces of glass separated by a 1 mm gap between during the curing process. The films were cut into pieces and were irradiated with a 6 MV X-ray beam to selected doses. The change in optical density was measured using a flatbed scanner and a spectrophotometer. Results: The results showed that all film formulations exhibited a linear response with dose and an absorption maximum at ∼ 590 nm. The formulation with 2 wt% LCV was ∼ 30% more sensitive to dose than the formulation with 1 wt% LCV. Both films were very deformable. In addition, the radiochromic response of the film was found to bleach over a short period of time (few weeks) allowing the film to be reused for dose verification measurements. Conclusion: Both film formulations displayed excellent sensitivity and linearity to radiation dose and thus can be used for the 2D dosimetry of clinical megavoltage and kilovoltage X-ray beams. In addition, the thickness of the film could easily be increased allowing for their potential use as a deformable bolus material. However, thicker films would need more optimization of the manufacturing procedure to ensure consistent material uniformity and sensitivity are recommended.

  10. Development of silicon monolithic arrays for dosimetry in external beam radiotherapy

    Energy Technology Data Exchange (ETDEWEB)

    Bisello, Francesca, E-mail: francesca.bisello@iba-group.com [IBA Dosimetry GmbH, Schwarzenbruck (Germany); Friedrich-Alexander Universität Erlangen—Nürnberg, Erlangen (Germany); Menichelli, David [IBA Dosimetry GmbH, Schwarzenbruck (Germany); Scaringella, Monica [University of Florence, Firenze (Italy); INFN—Florence Division, Sesto Fiorentino (Italy); Talamonti, Cinzia; Zani, Margherita; Bucciolini, Marta [University of Florence, Firenze (Italy); Azienda Ospedaliera Unversitaria Careggi, Firenze (Italy); Bruzzi, Mara [University of Florence, Firenze (Italy); INFN—Florence Division, Sesto Fiorentino (Italy)

    2015-10-01

    New tools for dosimetry in external beam radiotherapy have been developed during last years in the framework of the collaboration among the University of Florence, INFN Florence and IBA Dosimetry. The first step (in 2007) was the introduction in dosimetry of detector solutions adopted from high energy physics, namely epitaxial silicon as the base detector material and a guard ring in diode design. This allowed obtaining state of the art radiation hardness, in terms of sensitivity dependence on accumulated dose, with sensor geometry particularly suitable for the production of monolithic arrays with modular design. Following this study, a 2D monolithic array has been developed, based on 6.3×6.3 cm{sup 2} modules with 3 mm pixel pitch. This prototype has been widely investigated and turned out to be a promising tool to measure dose distributions of small and IMRT fields. A further linear array prototype has been recently design with improve spatial resolution (1 mm pitch) and radiation hardness. This 24 cm long device is constituted by 4×64 mm long modules. It features low sensitivity changes with dose (0.2%/kGy) and dose per pulse (±1% in the range 0.1–2.3 mGy/pulse, covering applications with flattened and unflattened photon fields). The detector has been tested with very satisfactory results as a tool for quality assurance of linear accelerators, with special regards to small fields, and proton pencil beams. In this contribution, the characterization of the linear array with unflattened MV X-rays, {sup 60}Co radiation and 226 MeV protons is reported. - Highlights: • A silicon monolithic 1D array with 1 mm pixel pitch was developed. • The detector was characterized with {sup 60}Co, unflattened MV X-rays, 226 MeV protons. • Dose linearity in clinical relevance range and dose profiles were measured. • The detector performs good agreement with reference detectors. • The technology is suitable in dose profiling in MV X-ray and proton therapy.

  11. Statistical process control applied to intensity modulated radiotherapy pretreatment controls with portal dosimetry

    International Nuclear Information System (INIS)

    Villani, N.; Noel, A.; Villani, N.; Gerard, K.; Marchesi, V.; Huger, S.; Noel, A.; Francois, P.

    2010-01-01

    Purpose The first purpose of this study was to illustrate the contribution of statistical process control for a better security in intensity modulated radiotherapy (I.M.R.T.) treatments. This improvement is possible by controlling the dose delivery process, characterized by pretreatment quality control results. So, it is necessary to put under control portal dosimetry measurements (currently, the ionisation chamber measurements were already monitored by statistical process control thanks to statistical process control tools). The second objective was to state whether it is possible to substitute ionisation chamber with portal dosimetry in order to optimize time devoted to pretreatment quality control. Patients and methods At Alexis-Vautrin center, pretreatment quality controls in I.M.R.T. for prostate and head and neck treatments were performed for each beam of each patient. These controls were made with an ionisation chamber, which is the reference detector for the absolute dose measurement, and with portal dosimetry for the verification of dose distribution. Statistical process control is a statistical analysis method, coming from industry, used to control and improve the studied process quality. It uses graphic tools as control maps to follow-up process, warning the operator in case of failure, and quantitative tools to evaluate the process toward its ability to respect guidelines: this is the capability study. The study was performed on 450 head and neck beams and on 100 prostate beams. Results Control charts, showing drifts, both slow and weak, and also both strong and fast, of mean and standard deviation have been established and have shown special cause introduced (manual shift of the leaf gap of the multi-leaf collimator). Correlation between dose measured at one point, given with the E.P.I.D. and the ionisation chamber has been evaluated at more than 97% and disagreement cases between the two measurements were identified. Conclusion The study allowed to

  12. Dosimetric validation of new semiconductor diode dosimetry system for intensity modulated radiotherapy

    Directory of Open Access Journals (Sweden)

    Rajesh Kinhikar

    2012-01-01

    Full Text Available Introduction: The new diode Isorad was validated for intensity modulated radiotherapy (IMRT and the observations during the validation are reported. Materials and Methods: The validation includes intrinsic precision, post-irradiation stability, dose linearity, dose-rate effect, angular response, source to surface (SSD dependence, field size dependence, and dose calibration. Results: The intrinsic precision of the diode was more than 1% (1 σ. The linearity found in the whole range of dose analyzed was 1.93% (R 2 = 1. The minimum and maximum variation in the measured and calculated dose were found to be 0.78% (with 25 MU at ioscentre and 4.8% (with 1000 MU at isocentre, respectively. The maximal variation in angular response with respect to arbitrary angle 0° found was 1.31%. The diode exhibited a 51.7% and 35% decrease in the response in the 35 cm and 20 cm SSD range, respectively. The minimum and the maximum variation in the measured dose from the diode and calculated dose were 0.82% (5 cm × 5 cm and 3.75% (30 cm × 30 cm, respectively. At couch 270°, the response of the diode was found to vary maximum by 1.4% with ΁ 60 gantry angle. Mean variation between measured dose with diode and planned dose by TPS was found to be 1.3% (SD 0.75 for IMRT patient-specific quality assurance. Conclusion: For the evaluation of IMRT, use of cylindrical diode is strongly recommended.

  13. Surface dosimetry for breast radiotherapy in the presence of immobilization cast material

    International Nuclear Information System (INIS)

    Kelly, Andrew; Hardcastle, Nicholas; Metcalfe, Peter; Cutajar, Dean; Quinn, Alexandra; Cardoso, Michael; Rosenfeld, Anatoly; Foo, Kerwyn; Barlin, Sheree

    2011-01-01

    Curative breast radiotherapy typically leaves patients with varying degrees of cosmetic damage. One problem interfering with cosmetically acceptable breast radiotherapy is the external contour for large pendulous breasts which often results in high doses to skin folds. Thermoplastic casts are often employed to secure the breasts to maintain setup reproducibility and limit the presence of skin folds. This paper aims to determine changes in surface dose that can be attributed to the use of thermoplastic immobilization casts. Skin dose for a clinical hybrid conformal/IMRT breast plan was measured using radiochromic film and MOSFET detectors at a range of water equivalent depths representative of the different skin layers. The radiochromic film was used as an integrating dosimeter, while the MOSFETs were used for real-time dosimetry to isolate the contribution of skin dose from individual IMRT segments. Strips of film were placed at various locations on the breast and the MOSFETs were used to measure skin dose at 16 positions spaced along the film strips for comparison of data. The results showed an increase in skin dose in the presence of the immobilization cast of up to 45.7% and 62.3% of the skin dose without the immobilization cast present as measured with Gafchromic EBT film and MOSFETs, respectively. The increase in skin dose due to the immobilization cast varied with the angle of beam incidence and was greatest when the beam was normally incident on the phantom. The increase in surface dose with the immobilization cast was greater under entrance dose conditions compared to exit dose conditions.

  14. Surface dosimetry for breast radiotherapy in the presence of immobilization cast material

    Energy Technology Data Exchange (ETDEWEB)

    Kelly, Andrew; Hardcastle, Nicholas; Metcalfe, Peter; Cutajar, Dean; Quinn, Alexandra; Cardoso, Michael; Rosenfeld, Anatoly [Centre for Medical Radiation Physics, University of Wollongong, Wollongong, NSW (Australia); Foo, Kerwyn [Sydney Medical School, University of Sydney, Sydney, NSW (Australia); Barlin, Sheree, E-mail: anatoly@uow.edu.au [Illawarra Cancer Care Centre, Wollongong Hospital, Wollongong, NSW (Australia)

    2011-02-21

    Curative breast radiotherapy typically leaves patients with varying degrees of cosmetic damage. One problem interfering with cosmetically acceptable breast radiotherapy is the external contour for large pendulous breasts which often results in high doses to skin folds. Thermoplastic casts are often employed to secure the breasts to maintain setup reproducibility and limit the presence of skin folds. This paper aims to determine changes in surface dose that can be attributed to the use of thermoplastic immobilization casts. Skin dose for a clinical hybrid conformal/IMRT breast plan was measured using radiochromic film and MOSFET detectors at a range of water equivalent depths representative of the different skin layers. The radiochromic film was used as an integrating dosimeter, while the MOSFETs were used for real-time dosimetry to isolate the contribution of skin dose from individual IMRT segments. Strips of film were placed at various locations on the breast and the MOSFETs were used to measure skin dose at 16 positions spaced along the film strips for comparison of data. The results showed an increase in skin dose in the presence of the immobilization cast of up to 45.7% and 62.3% of the skin dose without the immobilization cast present as measured with Gafchromic EBT film and MOSFETs, respectively. The increase in skin dose due to the immobilization cast varied with the angle of beam incidence and was greatest when the beam was normally incident on the phantom. The increase in surface dose with the immobilization cast was greater under entrance dose conditions compared to exit dose conditions.

  15. Surface dosimetry for breast radiotherapy in the presence of immobilization cast material

    Science.gov (United States)

    Kelly, Andrew; Hardcastle, Nicholas; Metcalfe, Peter; Cutajar, Dean; Quinn, Alexandra; Foo, Kerwyn; Cardoso, Michael; Barlin, Sheree; Rosenfeld, Anatoly

    2011-02-01

    Curative breast radiotherapy typically leaves patients with varying degrees of cosmetic damage. One problem interfering with cosmetically acceptable breast radiotherapy is the external contour for large pendulous breasts which often results in high doses to skin folds. Thermoplastic casts are often employed to secure the breasts to maintain setup reproducibility and limit the presence of skin folds. This paper aims to determine changes in surface dose that can be attributed to the use of thermoplastic immobilization casts. Skin dose for a clinical hybrid conformal/IMRT breast plan was measured using radiochromic film and MOSFET detectors at a range of water equivalent depths representative of the different skin layers. The radiochromic film was used as an integrating dosimeter, while the MOSFETs were used for real-time dosimetry to isolate the contribution of skin dose from individual IMRT segments. Strips of film were placed at various locations on the breast and the MOSFETs were used to measure skin dose at 16 positions spaced along the film strips for comparison of data. The results showed an increase in skin dose in the presence of the immobilization cast of up to 45.7% and 62.3% of the skin dose without the immobilization cast present as measured with Gafchromic EBT film and MOSFETs, respectively. The increase in skin dose due to the immobilization cast varied with the angle of beam incidence and was greatest when the beam was normally incident on the phantom. The increase in surface dose with the immobilization cast was greater under entrance dose conditions compared to exit dose conditions.

  16. A verification methodology for in vivo dosimetry in stereotactic radiotherapy; Uma metodologia para verificacao dosimetrica in vivo em radioterapia estereotaxica

    Energy Technology Data Exchange (ETDEWEB)

    Amaral, Leonardo L.; Oliveira, Harley F.; Fairbanks, Leandro R., E-mail: leonardo.fis@usp.br [Universidade de Sao Paulo (HCFMRP/USP), Ribeirao Preto, SP (Brazil). Faculdade de Medicina. Hospital das Clinicas; Nicolucci, Patricia; Netto, Thomaz G. [Universidade de Sao Paulo (FFCLRP/USP), Ribeirao Preto, SP (Brazil). Faculdade de Filosofia, Ciencias e Letras. Departamento de Fisica

    2012-12-15

    Radiotherapy of brain lesions near critical structures requires a high accuracy in the location and dose. The high precision is achieved by the location of the stereotactic apparatus. The accuracy in dose delivery should be accompanied by an accurate quality control in devices that involve the practice, however, still does not guarantee the dose at the time of therapy. The large number of fields and the small size of these conventional methods difficult dosimetry during treatment. The objective of this work was to develop a verification methodology in vivo dosimetry in stereotactic radiotherapy with the aid of the film radiochromic Linear Accelerator with multi leaf collimators Moduleaf. The technique uses film segments radiochromic Gafchromic EBT2, with dimensions of 1x1 cm{sup 2} in area outside the coupled micro-multileaf Moduleaf Siemens. These films were inserted in the region of the central axis of the beam. The films were irradiated and calibrated to obtain the factors that determine the size dependence of the dosimetric field. With these data, we designed a computer program which calculates the density of a film must acquire when subjected to an exposure in this setting. This study evaluated five non-coplanar plans, the first with 15 fields and the other with 25 fields. Before starting the procedure, the film segment is coupled to the device, and after the treatment, the relative density is evaluated and compared with the calculated. The average value of the verification at the time of radiation dosimetry compared with the calculated by the sheet was 1.5%. The data collected in this study showed a satisfactory agreement between measured and calculated by the program in the densitometer. Thus, a methodology was developed to verify in vivo dosimetry in radiotherapy and stereotactic linear accelerator collimators Moduleaf. (author)

  17. Utilization of thermoluminescent dosimetry in total skin electron beam radiotherapy of mycosis fungoides

    International Nuclear Information System (INIS)

    Antolak, John A.; Cundiff, Jackson H.; Ha, Chul S.

    1998-01-01

    Purpose: The purpose of this report is to discuss the utilization of thermoluminescent dosimetry (TLD) in total skin electron beam (TSEB) radiotherapy to: (a) compare patient dose distributions for similar techniques on different machines, (b) confirm beam calibration and monitor unit calculations, (c) provide data for making clinical decisions, and (d) study reasons for variations in individual dose readings. Methods and Materials: We report dosimetric results for 72 cases of mycosis fungoides, using similar irradiation techniques on two different linear accelerators. All patients were treated using a modified Stanford 6-field technique. In vivo TLD was done on all patients, and the data for all patients treated on both machines was collected into a database for analysis. Means and standard deviations (SDs) were computed for all locations. Scatter plots of doses vs. height, weight, and obesity index were generated, and correlation coefficients with these variables were computed. Results: The TLD results show that our current TSEB implementation is dosimetrically equivalent to the previous implementation, and that our beam calibration technique and monitor unit calculation is accurate. Correlations with obesity index were significant at several sites. Individual TLD results allow us to customize the boost treatment for each patient, in addition to revealing patient positioning problems and/or systematic variations in dose caused by patient variability. The data agree well with previously published TLD results for similar TSEB techniques. Conclusion: TLD is an important part of the treatment planning and quality assurance programs for TSEB, and routine use of TLD measurements for TSEB is recommended

  18. Characterization of phenolic pellets for ESR dosimetry in photon beam radiotherapy

    Energy Technology Data Exchange (ETDEWEB)

    Gallo, Salvatore; Veronese, Ivan [Universita degli Studi di Milano, Department of Physics, Milan (Italy); Istituto Nazionale di Fisica Nucleare, Sezione di Milano (Italy); Iacoviello, Giuseppina [Hospital ARNAS-Civico, Medical Physics Department, Palermo (Italy); Panzeca, Salvatore [Universita degli Studi di Palermo, Department of Physics and Chemistry, Palermo (Italy); Istituto Nazionale di Fisica Nucleare-Sezione di Catania, Catania (Italy); Bartolotta, Antonio; Longo, Anna [Universita degli Studi di Palermo, Department of Physics and Chemistry, Palermo (Italy); Dondi, Daniele [Universita degli Studi di Pavia, Department of Chemistry, Pavia (Italy); Istituto Nazionale di Fisica Nucleare, Sezione di Pavia (Italy); Gueli, Anna Maria [Istituto Nazionale di Fisica Nucleare-Sezione di Catania, Catania (Italy); Universita degli Studi di Catania, Department of Physics and Astronomy, PH3DRA Laboratories, Catania (Italy); Loi, Gianfranco; Mones, Eleonora [Azienda Ospedaliero Universitaria Maggiore della Carita, Medical Physics Department, Novara (Italy); Marrale, Maurizio [Universita degli Studi di Palermo, Department of Physics and Chemistry, Palermo (Italy); Istituto Nazionale di Fisica Nucleare-Sezione di Catania, Catania (Italy); Universita degli Studi di Palermo, Advanced Technologies Network Center (ATeN Center), Palermo (Italy)

    2017-11-15

    This work deals with the dosimetric features of a particular phenolic compound (IRGANOX 1076 {sup registered}) for dosimetry of clinical photon beams by using electron spin resonance (ESR) spectroscopy. After the optimization of the ESR readout parameters (namely modulation amplitude and microwave power) to maximise the signal without excessive spectrum distortions, basic dosimetric properties of laboratory-made phenolic dosimeters in pellet form, such as reproducibility, dose-response, sensitivity, linearity and dose rate dependence were investigated. The dosimeters were tested by measuring the depth dose profile of a 6 MV photon beam. A satisfactory intra-batch reproducibility of the ESR signal of the manufactured dosimeters was obtained. The ESR signal proved to increase linearly with increasing dose in the investigated dose range 1-13 Gy. The presence of an intrinsic background signal limits the minimum detectable dose to a value of approximately 0.6 Gy. Reliable and accurate assessment of the dose was achieved, independently of the dose rate. Such characteristics, together with the fact that IRGANOX 1076 {sup registered} is almost tissue-equivalent, and the stability of the ESR signal, make these dosimeters promising materials for ESR dosimetric applications in radiotherapy. (orig.)

  19. Internal dosimetry through GATE simulations of preclinical radiotherapy using a melanin-targeting ligand

    Science.gov (United States)

    Perrot, Y.; Degoul, F.; Auzeloux, P.; Bonnet, M.; Cachin, F.; Chezal, J. M.; Donnarieix, D.; Labarre, P.; Moins, N.; Papon, J.; Rbah-Vidal, L.; Vidal, A.; Miot-Noirault, E.; Maigne, L.

    2014-05-01

    The GATE Monte Carlo simulation platform based on the Geant4 toolkit is under constant improvement for dosimetric calculations. In this study, we explore its use for the dosimetry of the preclinical targeted radiotherapy of melanoma using a new specific melanin-targeting radiotracer labeled with iodine 131. Calculated absorbed fractions and S values for spheres and murine models (digital and CT-scan-based mouse phantoms) are compared between GATE and EGSnrc Monte Carlo codes considering monoenergetic electrons and the detailed energy spectrum of iodine 131. The behavior of Geant4 standard and low energy models is also tested. Following the different authors’ guidelines concerning the parameterization of electron physics models, this study demonstrates an agreement of 1.2% and 1.5% with EGSnrc, respectively, for the calculation of S values for small spheres and mouse phantoms. S values calculated with GATE are then used to compute the dose distribution in organs of interest using the activity distribution in mouse phantoms. This study gives the dosimetric data required for the translation of the new treatment to the clinic.

  20. TPS for Outer Planets

    Science.gov (United States)

    Venkatapathy, Ethiraj; Ellerby, D.; Gage, P.; Gasch, M.; Hwang, H.; Prabhu, D.; Stackpoole, M.; Wercinski, Paul

    2018-01-01

    This invited talk will provide an assessment of the TPS needs for Outer Planet In-situ missions to destinations with atmosphere. The talk will outline the drivers for TPS from destination, science, mission architecture and entry environment. An assessment of the readiness of the TPS, both currently available and under development, for Saturn, Titan, Uranus and Neptune are provided. The challenges related to sustainability of the TPS for future missions are discussed.

  1. PET/CT image registration: Preliminary tests for its application to clinical dosimetry in radiotherapy

    International Nuclear Information System (INIS)

    Banos-Capilla, M. C.; Garcia, M. A.; Bea, J.; Pla, C.; Larrea, L.; Lopez, E.

    2007-01-01

    The quality of dosimetry in radiotherapy treatment requires the accurate delimitation of the gross tumor volume. This can be achieved by complementing the anatomical detail provided by CT images through fusion with other imaging modalities that provide additional metabolic and physiological information. Therefore, use of multiple imaging modalities for radiotherapy treatment planning requires an accurate image registration method. This work describes tests carried out on a Discovery LS positron emission/computed tomography (PET/CT) system by General Electric Medical Systems (GEMS), for its later use to obtain images to delimit the target in radiotherapy treatment. Several phantoms have been used to verify image correlation, in combination with fiducial markers, which were used as a system of external landmarks. We analyzed the geometrical accuracy of two different fusion methods with the images obtained with these phantoms. We first studied the fusion method used by the PET/CT system by GEMS (hardware fusion) on the basis that there is satisfactory coincidence between the reconstruction centers in CT and PET systems; and secondly the fiducial fusion, a registration method, by means of least-squares fitting algorithm of a landmark points system. The study concluded with the verification of the centroid position of some phantom components in both imaging modalities. Centroids were estimated through a calculation similar to center-of-mass, weighted by the value of the CT number and the uptake intensity in PET. The mean deviations found for the hardware fusion method were: vertical bar Δx vertical bar ±σ=3.3 mm±1.0 mm and vertical bar Δy vertical bar ±σ=3.6 mm±1.0 mm. These values were substantially improved upon applying fiducial fusion based on external landmark points: vertical bar Δx vertical bar ±σ=0.7 mm±0.8 mm and vertical bar Δy vertical bar ±σ=0.3 mm±1.7 mm. We also noted that differences found for each of the fusion methods were similar for

  2. Dose verification of radiotherapy for lung cancer by using plastic scintillator dosimetry and a heterogeneous phantom

    DEFF Research Database (Denmark)

    Ottosson, Wiviann; Behrens, C. F.; Andersen, Claus E.

    2015-01-01

    of this study was to investigate the performance of a commercial treatment planning system (TPS) using a PSD and a specially designed thorax phantom with lung tumor inserts. 10 treatment plans of different complexity and phantom configurations were evaluated. Although the TPS agreed well with the measurements...... for the least complex tests, deviations of tumor dose > 4% were observed for some cases. This study underpins the dosimetric challenge in TPS calculations for clinically relevant heterogeneous geometries. The scintillator system, together with the special phantom, provides a promising tool for evaluation...

  3. The effect of different dopant concentration of tailor-made silica fibers in radiotherapy dosimetry

    Science.gov (United States)

    Begum, Mahfuza; Mizanur Rahman, A. K. M.; Zubair, H. T.; Abdul-Rashid, H. A.; Yusoff, Z.; Begum, Mahbuba; Alkhorayef, M.; Alzimami, K.; Bradley, D. A.

    2017-12-01

    In thermoluminescence (TL) material dopant concentration has an important effect on their characteristics as a ;radiation-sensor;. The study investigates dosimetric properties of four different concentration (4 mol%, 5 mol%, 7 mol% and 25 mol%) tailor-made Ge-doped silica fibers. The intention is to seek development of alternative TL materials that offer exceptional advantages over existing passive systems of dosimetry, including improved spatial resolution, a water impervious nature and low cost. Photon beams (6 MV and 10 MV) from a clinical linear accelerator were used for irradiation of the fiber samples over radiation therapy doses, ranging from 0.5 Gy to 8 Gy. SEM-EDX analysis was also performed to investigate the homogeneity of distribution of Ge dopant concentration from the fiber samples. The results of measurement were also compared with two of the more commonly used standard TLDs, TLD-100 (LiF: Mg,Ti-7.5% 6LiF) and TLD-700 ((7LiF: Mg,Ti-99.9%7LiF) chips respectively. The TL intensity of the fiber samples was found to strongly depend on Ge dopant concentration, with samples showing enhanced TL yields with decreasing Ge dopant concentration. 4 mol% Ge-doped silica fiber provided the greatest response whereas the 25 mol% samples showed the least, indicative of the well-known concentration quenching effects All fiber TLDs provided linear dose response over the delivered radiotherapy dose-range, the fibers also showing a weak dependence on photon beam energies in comparing the TL yields at 6 and 10 MV. The fading behavior of the different concentration Ge doped TLD-materials were also measured over a period of thirty (30) days subsequent to irradiation. The relative sensitivity of the samples with respect to standard TLD-100 were found to be 0.37, 0.26, 0.13 and 0.02 in respect of the 4, 5, 7 and 25 mol% fibers. The primary dosimetry peak, which was by far the most prominent of any other feature covered by the glow curve, was found to be around 244 °C using

  4. Three-dimensional printer-generated patient-specific phantom for artificial in vivo dosimetry in radiotherapy quality assurance.

    Science.gov (United States)

    Kamomae, Takeshi; Shimizu, Hidetoshi; Nakaya, Takayoshi; Okudaira, Kuniyasu; Aoyama, Takahiro; Oguchi, Hiroshi; Komori, Masataka; Kawamura, Mariko; Ohtakara, Kazuhiro; Monzen, Hajime; Itoh, Yoshiyuki; Naganawa, Shinji

    2017-12-01

    Pretreatment intensity-modulated radiotherapy quality assurance is performed using simple rectangular or cylindrical phantoms; thus, the dosimetric errors caused by complex patient-specific anatomy are absent in the evaluation objects. In this study, we construct a system for generating patient-specific three-dimensional (3D)-printed phantoms for radiotherapy dosimetry. An anthropomorphic head phantom containing the bone and hollow of the paranasal sinus is scanned by computed tomography (CT). Based on surface rendering data, a patient-specific phantom is formed using a fused-deposition-modeling-based 3D printer, with a polylactic acid filament as the printing material. Radiophotoluminescence glass dosimeters can be inserted in the 3D-printed phantom. The phantom shape, CT value, and absorbed doses are compared between the actual and 3D-printed phantoms. The shape difference between the actual and printed phantoms is less than 1 mm except in the bottom surface region. The average CT value of the infill region in the 3D-printed phantom is -6 ± 18 Hounsfield units (HU) and that of the vertical shell region is 126 ± 18 HU. When the same plans were irradiated, the dose differences were generally less than 2%. These results demonstrate the feasibility of the 3D-printed phantom for artificial in vivo dosimetry in radiotherapy quality assurance. Copyright © 2017 Associazione Italiana di Fisica Medica. Published by Elsevier Ltd. All rights reserved.

  5. SU-F-T-421: Dosimetry Change During Radiotherapy and Dosimetry Difference for Rigid and Deformed Registration in the Mid-Thoracic Esophageal Carcinoma

    Energy Technology Data Exchange (ETDEWEB)

    Tao, C; Liu, T; Chen, J; Zhu, J; Yin, Y [Shandong Cancer Hospital and Institute, Jinan, Shandong (China)

    2016-06-15

    Purpose: This study aimed to analyze dosimetry changes during radiotherapy for the mid-thoracic esophageal carcinoma, and investigate dosimetry difference between rigid and deformed registration. Methods: Twelve patients with primary middle thoracic esophageal carcinoma were selected randomly. Based on first CT scanning of each patient, plans-o were generated by experience physicists. After 20 fractions treatment, the corresponding plans-re were created with second CT scanning. And then, these two CT images were rigid and deformed registration respectively, and the dose was accumulated plan-o with plan-re. The dosimetry variation of these plans (plan-o: with 30 fractions, plan-rig: the accumulated dose with rigid registration and plan-def: the accumulated dose with deformed registration) were evaluated by paired T-test. Results: The V20 value of total lung were 32.68%, 30.3% and 29.71% for plan-o, plan-rig and plan-def respectively. The mean dose of total lung was 17.19 Gy, 16.67 Gy and 16.51 Gy for plan-o plan-rig and plan-def respectively. There were significant differences between plan-o and plan-rig or plan-def for both V20 and mean dose of total lung (with p= 0.003, p= 0.000 for V20 and p=0.008, p= 0.000 for mean dose respectively). There was no significant difference between plan-rig and plan-def (with p=0.118 for V20 and p=0.384 for mean dose). The max dose of spinal-cord was 41.95 Gy, 41.48 Gy and 41.4 Gy for plan-o, plan-rig and plan-def respectively. There were no significant differences for the max dose of spinal-cord between these plans. Conclusion: The target volume changes and anatomic position displacement of mid-thoracic esophageal carcinoma should not be neglected in clinics. These changes would cause overdose in normal tissue. Therefore, it is necessary to have another CT scanning and re-plan during the mid-thoracic esophageal carcinoma radiotherapy. And the dosimetry difference between rigid and deformed fusions was not found in this study.

  6. Considerations on the miniaturization of detectors for in vivo dosimetry in radiotherapy: A Monte Carlo study

    Energy Technology Data Exchange (ETDEWEB)

    Cunha, Micaela; Testa, Etienne [Université de Lyon, F-69622, Lyon (France); CNRS/IN2P3, Institut de Physique Nucléaire de Lyon (France); Beuve, Michael, E-mail: m.beuve@ipnl.in2p3.fr [Université de Lyon, F-69622, Lyon (France); CNRS/IN2P3, Institut de Physique Nucléaire de Lyon (France); Balosso, Jacques; Chaikh, Abdulhamid [Department of Radiation Oncology and Medical Physics, Grenoble Alpes University Hospital (CHUGA), Grenoble (France)

    2017-05-15

    The evolution of technology in radiotherapy nowadays allows us to deliver much higher doses to the target volumes, thanks to better absorbed dose distribution accuracy and conformation, while better sparing healthy tissues. In photon radiotherapy, higher precision usually entails employing small and moving beams. This emphasizes the role of in vivo dosimetry, which assesses internal absorbed dose rather than entrance dose. This, along with advances in materials science, results in a tendency towards the miniaturization of dosimeters. However, the stochastic nature of the radiation-matter interaction takes on greater importance at smaller scales, resulting in fluctuations in energy deposition whose effect may not be negligible. Miniaturization needs to take this into account. We estimated such fluctuations by Monte Carlo simulations considering energy deposition in cylindrical volumes of different sizes and for several absorbed dose values. We not only present and discuss the probability distributions of absorbed doses for a large range of target sizes (0.1–10 μm) and clinically relevant doses (0.1–10 Gy), but also derive an estimation of the risk of measuring an absorbed dose with a value outside a given interval of tolerance (3, 5 and 10%) around the expected dose. The distributions presented features consistent with the theory of microdosimetry. Those for dosimeter sizes smaller than 0.3 μm showed a very high dispersion in specific energy, while those for 10 μm dosimeters tended to become Gaussian and narrower with increasing absorbed dose. The probability of measuring an absorbed dose outside the defined interval of tolerance is close to 100% for the smallest size, regardless of the dose and the interval width considered. It decreases with increasing dose, dosimeter size and width of the interval of tolerance. The best results were obtained with 10 μm dosimeters, for which the probability of doses outside the tolerance range is always zero for absorbed

  7. Real-time in vivo luminescence dosimetry in radiotherapy and mammography using Al2O3:C

    International Nuclear Information System (INIS)

    Aznar, M.C.

    2005-07-01

    New treatment and clinical imaging techniques have created a need for accurate and practical in vivo dosimeters in radiation medicine. This work describes the development of a new optical-fiber radiation dosimeter system, based on radioluminescence (RL) and optically stimulated luminescence (OSL) from carbon-doped aluminium oxide (Al2O3:C), for applications in radiotherapy and mammography. This system offers several features, such as a small detector, high sensitivity, real-time read-out, and the ability to measure both dose rate and absorbed dose. Measurement protocols and algorithms for the correction of responses were developed to enable a reliable absorbed dose assessment from the RL and OSL signals. At radiotherapy energies, the variation of the signal with beam parameters was smaller than 1% (1 SD). Treatment-like experiments in phantoms, and in vivo measurements during complex patient treatments (such as intensity-modulated radiation therapy) indicate that the RL/OSL dosimetry system can reliably measure the absorbed dose within 2%. The real-time RL signal also enables an individual dose assessment from each field. The RL/OSL dosimetry system was also used during mammography examinations. In such conditions, the reproducibility of the measurements showed to be around 3%. In vivo measurements on three patients showed that the presence of the RL/OSL probes did not degrade the diagnostic quality of the radiograph and that the system could be used to measure exit doses (i.e., absorbed doses on the inferior surface of the breast). A Monte Carlo study proved that the energy dependence of the RL/OSL system at these low energies could be reduced by optimizing the design of the probes. It is concluded that the new RL/OSL dosimetry system shows considerable potential for applications in both radiotherapy and mammography. (au)

  8. Computational dosimetry and risk assessment of radioinduced cancer: studies in mammary glands radiotherapy, radiopharmaceuticals and internal contamination

    International Nuclear Information System (INIS)

    Mendes, Bruno Melo

    2017-01-01

    The use of Ionizing radiation (IR) in medicine has increased considerably. The benefits generated by diagnostic and therapy techniques with IR are proven. Nevertheless, the risks arising from these uses should not be underestimated. Justification, a basic radiation protection, states that the benefits from exposures must outweigh detriment. The cancer induction is one of the detriment components. Thus, the study of the benefit/detriment ratio should take into account cancer incidence and mortality estimations resulting from a given diagnosis or therapy radiological technique. The risk of cancer induction depends on the absorbed doses in the irradiated organs and tissues. Thus, IR dosimetry is essential to evaluate the benefit/detriment ratio. The present work aims to perform computational dosimetric evaluations and estimations of cancer induction risk after ionizing radiation exposure. The investigated situations cover nuclear medicine, radiological contamination and radiotherapy fields. Computational dosimetry, with MCNPx Monte Carlo Code, was used as a tool to calculate the absorbed dose in the interest organs of the voxelized human models. The simulations were also used to obtain calibration factors and optimization of in vivo monitoring systems for internal contamination dosimetry. A breast radiotherapy (RT) standard protocol was simulated using the MCNPx code. The calculation of the radiation-induced cancer risk was adapted from the BEIR VII methodology for the Brazilian population. The absorbed doses used in the risk calculations were obtained through computational simulations of different exposure scenarios. During this work, two new computational phantoms, DM B RA and VW, were generated from tomographic images. Additional twelve voxelized phantoms, including the reference phantoms, RCP A M and RCP A F, and the child, baby, and fetus models were adapted to run on MCNP. Internal Dosimetry Protocols (IDP) for radiopharmaceuticals and for internal contamination

  9. In vivo real-time rectal wall dosimetry for prostate radiotherapy

    Science.gov (United States)

    Hardcastle, Nicholas; Cutajar, Dean L.; Metcalfe, Peter E.; Lerch, Michael L. F.; Perevertaylo, Vladimir L.; Tomé, Wolfgang A.; Rosenfeld, Anatoly B.

    2010-07-01

    Rectal balloons are used in external beam prostate radiotherapy to provide reproducible anatomy and rectal dose reductions. This is an investigation into the combination of a MOSFET radiation detector with a rectal balloon for real-time in vivo rectal wall dosimetry. The MOSFET used in the study is a radiation detector that provides a water equivalent depth of measurement of 70 µm. Two MOSFETs were combined in a face-to-face orientation. The reproducibility, sensitivity and angular dependence were measured for the dual MOSFET in a 6 MV photon beam. The dual MOSFET was combined with a rectal balloon and irradiated with hypothetical prostate treatments in a phantom. The anterior rectal wall dose was measured in real time and compared with the planning system calculated dose. The dual MOSFET showed angular dependence within ±2.5% in the azimuth and +2.5%/-4% in the polar axes. When compared with an ion chamber measurement in a phantom, the dual MOSFET agreed within 2.5% for a range of radiation path lengths and incident angles. The dual MOSFET had reproducible sensitivity for fraction sizes of 2-10 Gy. For the hypothetical prostate treatments the measured anterior rectal wall dose was 2.6 and 3.2% lower than the calculated dose for 3DCRT and IMRT plans. This was expected due to limitations of the dose calculation method used at the balloon cavity interface. A dual MOSFET combined with a commercial rectal balloon was shown to provide reproducible measurements of the anterior rectal wall dose in real time. The measured anterior rectal wall dose agreed with the expected dose from the treatment plan for 3DCRT and IMRT plans. The dual MOSFET could be read out in real time during the irradiation, providing the capability for real-time dose monitoring of the rectal wall dose during treatment.

  10. A deformable head and neck phantom with in-vivo dosimetry for adaptive radiotherapy quality assurance

    Energy Technology Data Exchange (ETDEWEB)

    Graves, Yan Jiang [Center for Advanced Radiotherapy Technologies and Department of Radiation Medicine and Applied Sciences, University of California San Diego, La Jolla, California 92037-0843 and Department of Physics, University of California San Diego, La Jolla, California 92093 (United States); Smith, Arthur-Allen; Mcilvena, David; Manilay, Zherrina; Lai, Yuet Kong [Department of Mechanical and Aerospace Engineering, University of California San Diego, La Jolla, California 92093 (United States); Rice, Roger; Mell, Loren; Cerviño, Laura, E-mail: lcervino@ucsd.edu, E-mail: steve.jiang@utsouthwestern.edu [Center for Advanced Radiotherapy Technologies and Department of Radiation Medicine and Applied Sciences, University of California San Diego, La Jolla, California 92037-0843 (United States); Jia, Xun; Jiang, Steve B., E-mail: lcervino@ucsd.edu, E-mail: steve.jiang@utsouthwestern.edu [Center for Advanced Radiotherapy Technologies and Department of Radiation Medicine and Applied Sciences, University of California San Diego, La Jolla, California 92037-0843 and Department of Radiation Oncology, University of Texas Southwestern Medical Center, Dallas, Texas 75235 (United States)

    2015-04-15

    Purpose: Patients’ interfractional anatomic changes can compromise the initial treatment plan quality. To overcome this issue, adaptive radiotherapy (ART) has been introduced. Deformable image registration (DIR) is an important tool for ART and several deformable phantoms have been built to evaluate the algorithms’ accuracy. However, there is a lack of deformable phantoms that can also provide dosimetric information to verify the accuracy of the whole ART process. The goal of this work is to design and construct a deformable head and neck (HN) ART quality assurance (QA) phantom with in vivo dosimetry. Methods: An axial slice of a HN patient is taken as a model for the phantom construction. Six anatomic materials are considered, with HU numbers similar to a real patient. A filled balloon inside the phantom tissue is inserted to simulate tumor. Deflation of the balloon simulates tumor shrinkage. Nonradiopaque surface markers, which do not influence DIR algorithms, provide the deformation ground truth. Fixed and movable holders are built in the phantom to hold a diode for dosimetric measurements. Results: The measured deformations at the surface marker positions can be compared with deformations calculated by a DIR algorithm to evaluate its accuracy. In this study, the authors selected a Demons algorithm as a DIR algorithm example for demonstration purposes. The average error magnitude is 2.1 mm. The point dose measurements from the in vivo diode dosimeters show a good agreement with the calculated doses from the treatment planning system with a maximum difference of 3.1% of prescription dose, when the treatment plans are delivered to the phantom with original or deformed geometry. Conclusions: In this study, the authors have presented the functionality of this deformable HN phantom for testing the accuracy of DIR algorithms and verifying the ART dosimetric accuracy. The authors’ experiments demonstrate the feasibility of this phantom serving as an end

  11. Experience with in vivo diode dosimetry for verifying radiotherapy dose delivery: Practical implementation of cost-effective approaches

    International Nuclear Information System (INIS)

    Thwaites, D.I.; Blyth, C.; Carruthers, L.; Elliott, P.A.; Kidane, G.; Millwater, C.J.; MacLeod, A.S.; Paolucci, M.; Stacey, C.

    2002-01-01

    A systematic programme of in vivo dosimetry using diodes to verify radiotherapy delivered doses began in Edinburgh in 1992. The aims were to investigate the feasibility of routine systematic use of diodes as part of a comprehensive QA programme, to carry out clinical pilot studies to assess the accuracy of dose delivery on each machine and for each site and technique, to identify and rectify systematic deviations, to assess departmental dosimetric precision and to compare to clinical requirements. A further aim was to carry out a cost-benefit evaluation based on the results from the pilot studies to consider how best to use diodes routinely

  12. Dosimetry comparison of irradiation with conformal radiotherapy, intensity modulated radiotherapy, conformal radiotherapy in stereotactic conditions and robotic stereotactic radiotherapy for benign brain tumours; Comparaison dosimetrique de la radiotherapie conformationnelle, la radiotherapie conformationnelle avec modulation d'intensite, la radiotherapie conformationnelle en conditions stereotaxiques et la radiotherapie en conditions stereotaxiques robotisee des tumeurs cerebrales benignes

    Energy Technology Data Exchange (ETDEWEB)

    Spasic, E.; Noel, A. [Departement de radiophysique, centre Alexis-Vautrin, avenue de Bourgogne, 54511 Vandoeuvre-les-Nancy cedex (France); UMR 7039 CNRS, centre de recherche en automatique de Nancy (Cran), BP 239, 54506 Vandoeuvre-les-Nancy cedex (France); Cran UMR 7039, faculte des sciences et techniques, universite Henri-Poincare Nancy 1, BP 239, 54506 Vandoeuvre-les-Nancy cedex (France); Cran UMR 7039, institut national polytechnique de Lorraine, BP 239, 54506 Vandoeuvre-les-Nancy cedex (France); Buchheit, I.; Bernier, V. [Departement de radiophysique, centre Alexis-Vautrin, avenue de Bourgogne, 54511 Vandoeuvre-les-Nancy cedex (France)

    2011-07-15

    Purpose. - To compare several techniques in order to determine the best treatment for benign brain tumours. Methods and patients. - A retrospective study was performed for five patients who received 3D-conformal radiotherapy, intensity modulated radiotherapy or CyberKnife{sup R}. These patients had a meningioma, a pituitary tumour, a cranio-pharyngioma or a neurinoma. In each case, these treatment plans were optimised and compared with the three other dosimetries. Radiobiological or positioning parameters were evaluated, as well as dosimetric parameters, in order to compare treatments with different characteristics. Results. - The dosimetric parameters showed that the choice of treatment seemed to be determined mostly by tumour size, shape and proximity with organs at risk (not tumour localisation). Whereas the results showed no significant deviations with regards to the radiobiological parameters. Therefore, with these parameters, it was difficult to give priority to a treatment. Conclusions. - With regards to benign brain tumours of medium or large size, intensity modulated radiotherapy seemed the recommended treatment. It enabled to obtain a good ratio between efficacy and toxicity for tumours that are really close to organs at risk. Concerning small benign brain tumours, the CyberKnife{sup R} was probably the best treatment. (authors)

  13. GATE: computation code for medical imagery, radiotherapy and dosimetry; GATE: code de calcul pour l'imagerie medicale, la radiotherapie et la dosimetrie

    Energy Technology Data Exchange (ETDEWEB)

    Jan, S. [CEA Direction des Sciences du Vivant, Institut d ' Imagerie Bio-Medicale, Service Hospitalier Frederic Joliot, 4 pl. du Gn. Leclerc 91401 Orsay Cedex (France)

    2010-07-01

    The author presents the GATE code, a simulation software based on the Geant4 development environment developed by the CERN (the European organization for nuclear research) which enables Monte-Carlo type simulation to be developed for tomography imagery using ionizing radiation, and radiotherapy examinations (conventional and hadron therapy) to be simulated. The authors concentrate on the use of medical imagery in carcinology. They comment some results obtained in nuclear imagery and in radiotherapy

  14. Experimental dosimetry in conformal breast teletherapy compared with the planning system

    International Nuclear Information System (INIS)

    Nogueira, Luciana Batista; Silva, Hugo Leonardo Lemos; Passos Ribeiro de Campos, Tarcísio

    2015-01-01

    The objective of this study was to compare and analyse the absorbed dose profiles from the conformal radiotherapy planning and experimental dosimetry taken in a breast anthropomorphic and anthropometric phantom. Conformal radiotherapy planning was elaborated in the Treatment Planning System (TPS). EBT2 Gafchromic radiochromic films were applied as dosimeters, positioned internally and superficially in the breast phantom. The standard radiation protocol was applied in the breast phantom. The films were digitalised, and their responses were analysed in RGB. The optical densities were processed, reproducing the spatial dose distribution. - Highlights: • Distributions of absorbed doses were generated by the TPS and measured by radiochromic films. • The breast phantom simulated a human breast in position for treatment. • A large portion of the glandular tissue absorbed doses that were equivalent to the radiotherapy planning. • There were regions of hot spots and small areas of under dosage in deeper areas at the lung interface

  15. In vivo Tl dosimetry for the quality control in Radiotherapy with 60 Co and brachytherapy of low dose rate

    International Nuclear Information System (INIS)

    Velez, G.; Bustos, S.; Balmaceda, O.; Gutierrez, S.; Ferraris, M.

    1998-01-01

    In vivo dosimetry is used every time with more frequency as a valuable tool for the quality control in Radiotherapy. The measurements of input and output doses provide us information about the technique accuracy or the treatment procedure used; likewise the dose measurement which rectum or bladder receive in gynecologic implants contribute to the improving and adjusting the procedures in brachytherapy. Besides, it may be identify systematic errors in particular situations which allow to optimize the treatment and to minimize errors. It was realized a study at the Radiotherapy service in San Roque Hospital (Cordoba) to control the procedures used in the treatment of distinct oncologic pathologies. Its were selected patients, which were realized the routine planning with the planning system of computerized treatments Prowess 3000, that later its were controlled with In vivo thermoluminescent dosimetry using the Ceprocor Services (Cordoba). Its were realized dose skin measurements in treatments of mammary gland, pelvis, thorax, head and neck and it were measured doses in body cavities, as oral cavity, rectum, esophagus, etc. arranging the TLD inside special catheters. In the case of dose skin, the dosemeters were arranged in acrylic porta-dosemeters, at pairs, which later they were enveloped and sealed. It was founded a very good agreement among the In vivo measurements and the predicted by the planner. In some cases, the control allows to modify the treatment for to avoid over or sub dosages of the distinct organs affected by the radiation field. (Author)

  16. Development of a silicon diode detector for skin dosimetry in radiotherapy.

    Science.gov (United States)

    Vicoroski, Nikolina; Espinoza, Anthony; Duncan, Mitchell; Oborn, Bradley M; Carolan, Martin; Metcalfe, Peter; Menichelli, David; Perevertaylo, Vladimir L; Lerch, Michael L F; Rosenfeld, Anatoly B; Petasecca, Marco

    2017-10-01

    The aim of in vivo skin dosimetry was to measure the absorbed dose to the skin during radiotherapy, when treatment planning calculations cannot be relied on. It is of particularly importance in hypo-fractionated stereotactic modalities, where excessive dose can lead to severe skin toxicity. Currently, commercial diodes for such applications are with water equivalent depths ranging from 0.5 to 0.8 mm. In this study, we investigate a new detector for skin dosimetry based on a silicon epitaxial diode, referred to as the skin diode. The skin diode is manufactured on a thin epitaxial layer and packaged using the "drop-in" technology. It was characterized in terms of percentage depth dose, dose linearity, and dose rate dependence, and benchmarked against the Attix ionization chamber. The response of the skin diode in the build-up region of the percentage depth dose (PDD) curve of a 6 MV clinical photon beam was investigated. Geant4 radiation transport simulations were used to model the PDD in order to estimate the water equivalent measurement depth (WED) of the skin diode. Measured output factors using the skin diode were compared with the MOSkin detector and EBT3 film at 10 cm depth and at surface at isocenter of a water equivalent phantom. The intrinsic angular response of the skin diode was also quantified in charge particle equilibrium conditions (CPE) and at the surface of a solid water phantom. Finally, the radiation hardness of the skin diode up to an accumulated dose of 80 kGy using photons from a Co-60 gamma source was evaluated. The PDD curve measured with the skin diode was within 0.5% agreement of the equivalent Geant4 simulated curve. When placed at the phantom surface, the WED of the skin diode was estimated to be 0.075 ± 0.005 mm from Geant4 simulations and was confirmed using the response of a corrected Attix ionization chamber placed at water equivalent depth of 0.075 mm, with the measurement agreement to within 0.3%. The output factor measurements at

  17. Comparison of radiotherapy dosimetry for 3D-CRT, IMRT, and SBRT based on electron density calibration

    International Nuclear Information System (INIS)

    Kartutik, K; Pawiro, S A; Wibowo, W E

    2016-01-01

    Accurate calculation of dose distribution affected by inhomogeneity tissue is required in radiotherapy planning. This study was performed to determine the ratio between radiotherapy planning using 3D-CRT, IMRT, and SBRT based on a calibrated curve of CT-number in the lung for different target's shape in 3D-CRT, IMRT, and spinal cord for SBRT. Calibration curves of CT-number were generated under measurement basis and introduced into TPS, then planning was performed for 3D-CRT, IMRT, and SBRT with 7, and 15 radiation fields. Afterwards, planning evaluation was performed by comparing the DVH curve, HI, and CI. 3D-CRT and IMRT produced the lowest HI at calibration curve of CIRS 002LFC with the value 0.24 and 10. Whereas SBRT produced the lowest HI on a linear calibration curve with a value of 0.361. The highest CI in IMRT and SBRT technique achieved using a linear calibration curve was 0.97 and 1.77 respectively. For 3D-CRT, the highest CI was obtained by using calibration curve of CIRS 062M with the value of 0.45. From the results of CI and HI, it is concluded that the calibration curve of CT-number does not significantly differ with Schneider's calibrated curve, and inverse planning gives a better result than forward planning. (paper)

  18. Dosimetry characterization of a multibeam radiotherapy treatment for age-related macular degeneration

    International Nuclear Information System (INIS)

    Lee, Choonsik; Chell, Erik; Gertner, Michael; Hansen, Steven; Howell, Roger W.; Hanlon, Justin; Bolch, Wesley E.

    2008-01-01

    Age-related macular degeneration (ARMD) is a major health problem worldwide. Advanced ARMD, which ultimately leads to profound vision loss, has dry and wet forms, which account for 20% and 80% of cases involving severe vision loss, respectively. A new device and approach for radiation treatment of ARMD has been recently developed by Oraya Therapeutics, Inc. (Newark, CA). The goal of the present study is to provide a initial dosimetry characterization of the proposed radiotherapy treatment via Monte Carlo radiation transport simulation. A 3D eye model including cornea, anterior chamber, lens, orbit, fat, sclera, choroid, retina, vitreous, macula, and optic nerve was carefully designed. The eye model was imported into the MCNPX2.5 Monte Carlo code and radiation transport simulations were undertaken to obtain absorbed doses and dose volume histograms (DVH) to targeted and nontargeted structures within the eye. Three different studies were undertaken to investigate (1) available beam angles that maximized the dose to the macula target tissue, simultaneously minimizing dose to normal tissues, (2) the energy dependency of the DVH for different x-ray energies (80, 100, and 120 kVp), and (3) the optimal focal spot size among options of 0.0, 0.4, 1.0, and 5.5 mm. All results were scaled to give 8 Gy to the macula volume, which is the current treatment requirement. Eight beam treatment angles are currently under investigation. In all eight beam angles, the source-to-target distance is 13 cm, and the polar angle of entry is 30 degree sign from the geometric axis of the eye. The azimuthal angle changes in eight increments of 45 degree sign in a clockwise fashion, such that an azimuthal angle of 0 degree sign corresponds to the 12 o'clock position when viewing the treated eye. Based on considerations of nontarget tissue avoidance, as well as facial-anatomical restrictions on beam delivery, treatment azimuthal angles between 135 degree sign and 225 degree sign would be available

  19. Dosimetry characterization of a multibeam radiotherapy treatment for age-related macular degeneration

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Choonsik; Chell, Erik; Gertner, Michael; Hansen, Steven; Howell, Roger W.; Hanlon, Justin; Bolch, Wesley E. [Department of Nuclear and Radiological Engineering, University of Florida, Gainesville, Florida 32611 (United States); Oraya Therapeutics, Inc., Newark, California 94560 (United States); Department of Radiology, University of Medicine and Dentistry of New Jersey, Newark, New Jersey 07103 (United States); Department of Nuclear and Radiological Engineering, University of Florida, Gainesville, Florida 32611 (United States); Departments of Nuclear and Radiological and Biomedical Engineering, University of Florida, Gainesville, Florida 32611 (United States)

    2008-11-15

    Age-related macular degeneration (ARMD) is a major health problem worldwide. Advanced ARMD, which ultimately leads to profound vision loss, has dry and wet forms, which account for 20% and 80% of cases involving severe vision loss, respectively. A new device and approach for radiation treatment of ARMD has been recently developed by Oraya Therapeutics, Inc. (Newark, CA). The goal of the present study is to provide a initial dosimetry characterization of the proposed radiotherapy treatment via Monte Carlo radiation transport simulation. A 3D eye model including cornea, anterior chamber, lens, orbit, fat, sclera, choroid, retina, vitreous, macula, and optic nerve was carefully designed. The eye model was imported into the MCNPX2.5 Monte Carlo code and radiation transport simulations were undertaken to obtain absorbed doses and dose volume histograms (DVH) to targeted and nontargeted structures within the eye. Three different studies were undertaken to investigate (1) available beam angles that maximized the dose to the macula target tissue, simultaneously minimizing dose to normal tissues, (2) the energy dependency of the DVH for different x-ray energies (80, 100, and 120 kVp), and (3) the optimal focal spot size among options of 0.0, 0.4, 1.0, and 5.5 mm. All results were scaled to give 8 Gy to the macula volume, which is the current treatment requirement. Eight beam treatment angles are currently under investigation. In all eight beam angles, the source-to-target distance is 13 cm, and the polar angle of entry is 30 degree sign from the geometric axis of the eye. The azimuthal angle changes in eight increments of 45 degree sign in a clockwise fashion, such that an azimuthal angle of 0 degree sign corresponds to the 12 o'clock position when viewing the treated eye. Based on considerations of nontarget tissue avoidance, as well as facial-anatomical restrictions on beam delivery, treatment azimuthal angles between 135 degree sign and 225 degree sign would be

  20. Manual of dosimetry in radiotherapy. A practical guide for testing and calibrating equipment used in external beam treatments

    International Nuclear Information System (INIS)

    Massey, J.B.

    1971-01-01

    In order to achieve safe and efficient radiotherapy, one should respect a number of technical criteria, meaning that the irradiation facility should be adapted every time to the specific patient and the dose received by the patient should be fixed. If the radio therapist should decide about the characteristics of the treatment, he might not have the technical education needed to ensure that the applied devices are appropriate for obtaining the wanted results. This is the responsibility of the medical radio physicist. Unfortunately many countries lack qualified medical doctors experienced in radiotherapy. Although these countries can supply numerous hospitals with radiotherapeutic devices and x-ray sources they cannon make good use of them. That is why the IAEA, WHO and Pan-American Health Organization organised an experts team to study the problems of dosimetry in the radiotherapeutic centres. The objective of the present manual is to supply specialists in radiotherapy with practical instructions which will enable them to apply precise physical data on the irradiation volume and applied doses

  1. A fast dual wavelength laser beam fluid-less optical CT scanner for radiotherapy 3D gel dosimetry II: dosimetric performance

    Science.gov (United States)

    Ramm, Daniel

    2018-02-01

    New clinical radiotherapy dosimetry systems need comprehensive demonstration of measurement quality. Practicality and reliability are other important aspects for clinical dosimeters. In this work the performance of an optical CT scanner for true 3D dosimetry is assessed using a radiochromic gel dosimeter. The fluid-less scanner utilised dual lasers to avoid the necessity for pre-irradiation scans and give greater robustness of image quality, enhancing practicality. Calibration methods using both cuvettes and reconstructed volumes were developed. Dosimetric accuracy was similar for dual and single wavelength measurements, except that cuvette calibration reliability was reduced for dual wavelength without pre-irradiation scanning. Detailed performance parameters were specified for the dosimetry system indicating the suitability for clinical use. The most significant limitations of the system were due to the gel dosimeter rather than the optical CT scanner. Quality assurance guidelines were developed to maintain dosimetry system performance in routine use.

  2. Dosimetry for synchrotron stereotactic radiotherapy: Monte Carlo simulations and radiosensitive gels; Dosimetrie pour la radiotherapie stereotaxique en rayonnement synchrotron: calculs Monte-Carlo et gels radiosensibles

    Energy Technology Data Exchange (ETDEWEB)

    Boudou, C

    2006-09-15

    High grade gliomas are extremely aggressive brain tumours. Specific techniques combining the presence of high atomic number elements within the tumour to an irradiation with a low x-rays (below 100 keV) beam from a synchrotron source were proposed. For the sake of clinical trials, the use of treatment planning system has to be foreseen as well as tailored dosimetry protocols. Objectives of this thesis work were (1) the development of a dose calculation tools based on Monte Carlo code for particles transport and (2) the implementation of an experimental method for the three dimensional verification of the dose delivered. The dosimetric tool is an interface between tomography images from patient or sample and the M.C.N.P.X. general purpose code. Besides, dose distributions were measured through a radiosensitive polymer gel, providing acceptable results compared to calculations.

  3. Injectable silver nanosensors: in vivo dosimetry for external beam radiotherapy using positron emission tomography

    DEFF Research Database (Denmark)

    Christensen, Anders Nymark; Rydhög, J. S.; Søndergaard, Rikke Vicki

    2016-01-01

    , which enables post treatment verification of the delivered dose using positron emission tomography imaging. The silver-nanosensor was investigated in a tissue equivalent thorax phantom using clinical settings and workflow for both standard fractionated radiotherapy (2 Gy) and stereotactic radiotherapy...

  4. Conformal radiotherapy using multileaf collimation: quality assurance and in vivo dosimetry

    Energy Technology Data Exchange (ETDEWEB)

    Aletti, P. [Centre A. Vautrin, Nancy (France)

    1995-12-01

    The application of quality assurance principles in three dimensional conformal therapy is discussed.Critical requirements in three dimensional radiotherapy are the patient immobilization, the location, and the delivered dose. General recommendations with respect to the equipment for conformal radiotherapy and personnel are made.

  5. Conformal radiotherapy using multileaf collimation: quality assurance and in vivo dosimetry

    International Nuclear Information System (INIS)

    Aletti, P.

    1995-01-01

    The application of quality assurance principles in three dimensional conformal therapy is discussed.Critical requirements in three dimensional radiotherapy are the patient immobilization, the location, and the delivered dose. General recommendations with respect to the equipment for conformal radiotherapy and personnel are made

  6. In-vivo dosimetry in external radiotherapy with amorphous silicon Portal Imaging Devices: from method to clinical validation

    International Nuclear Information System (INIS)

    Boissard, Philippe

    2012-01-01

    In vivo dose verification is used to prevent major deviations between the prescribed dose and the dose really delivered to the patient. This quality control was, nationally and internationally, widely recommended by scientific organizations. In France, its implementation and its use are now regulated. To do this, small detectors are fixed on the patient skin at the beginning of the treatment. However, the treatment delay is increased and not all treatment techniques could be assessed, such as IMRT plans (Intensity Modulated Radiation Therapy). In this context, Transit dosimetry performed with Electronic Portal Imaging Devices (EPIDs) appears as an interesting alternative for in vivo dose verification. During the treatment session, a transit dose is measured with the EPID, in two dimensions, and the dose in the patient is estimated from back projection of the portal dose. This work presents a quick and simple alternative method for verification of dose delivered to the patient using photon beams. Verifications in cases of complexes patient shapes and Intensity Modulated Radiation Therapy (IMRT) have been improved by using a Clarkson-Cunningham's integration method. 46 phantom test cases were designed to assess the accuracy of the method for 4, 6, 10 and 20 MV photon beams. For some points of interest the dose reconstructed by the method is compared to the dose measured with an ionization chamber. An additional in vivo uncertainty due to day to day deviations is defined and investigated. In the same time, a clinical study was driven during three years. In vivo dosimetry was performed for 494 patients treated for various tumors sites. Most of the patients were treated for a prostate cancer using IMRT. The in vivo dose is here compared to the dose calculated by the Treatment Planning System, TPS. The results of these two ways of validations are within the accepted tolerance of classical in vivo dosimetry. From the phantom study, we have estimated that the standard

  7. Dosimetry TL 'in vivo' for the quality control in radiotherapy with Co-60 and brachytherapy of low dose rate

    International Nuclear Information System (INIS)

    Velez, G.; Balmaceda, O.; Gutierrez, S.; Ferraris, M.; Bustos, S.

    1998-01-01

    Full text: The dosimetry 'in vivo' is used frequently as a valuable tool for the quality control in radiotherapy. Measurements of the entry and exit doses provide us of information on the precision of the technique or the procedure of used treatment; the measurement of the doses in rectal or bladder in gynecological implants contribute to perfect or to adjust the procedures in brachytherapy. Also systematic errors can be identified in particular situations that allow to optimize the treatment and to minimize errors. A study in the service of Radiotherapy of the San Roque Hospital, was realized for to control the procedures used in the treatment of different cancer therapy. Patients were selected, to which were carried out a routine planning with the system of planning of on line treatment Prowess 3000 that then were controlled with thermoluminescent dosemeters 'in vivo' using the Ceprocor Services. Skin doses were measurement in treatment of breast, pelvis, thorax, head and neck, and doses was measured in cavities of the body as oral cavity, rectal, esophagus, etc., placing the TLD inside special catheters. In the case of doses in skin, the dosimeters was placed in acrylic badges. A very good agreement was found between the measurements 'in vivo' and the plans of the planner. In some cases the control allowed to modify the doses to avoid organs damage for the radiation fields. (author) [es

  8. Accuracy of dose planning for prostate radiotherapy in the presence of metallic implants evaluated by electron spin resonance dosimetry

    International Nuclear Information System (INIS)

    Alves, G.G.; Kinoshita, A.; Oliveira, H.F. de; Guimarães, F.S.; Amaral, L.L.; Baffa, O.

    2015-01-01

    Radiotherapy is one of the main approaches to cure prostate cancer, and its success depends on the accuracy of dose planning. A complicating factor is the presence of a metallic prosthesis in the femur and pelvis, which is becoming more common in elderly populations. The goal of this work was to perform dose measurements to check the accuracy of radiotherapy treatment planning under these complicated conditions. To accomplish this, a scale phantom of an adult pelvic region was used with alanine dosimeters inserted in the prostate region. This phantom was irradiated according to the planned treatment under the following three conditions: with two metallic prostheses in the region of the femur head, with only one prosthesis, and without any prostheses. The combined relative standard uncertainty of dose measurement by electron spin resonance (ESR)/alanine was 5.05%, whereas the combined relative standard uncertainty of the applied dose was 3.35%, resulting in a combined relative standard uncertainty of the whole process of 6.06%. The ESR dosimetry indicated that there was no difference (P>0.05, ANOVA) in dosage between the planned dose and treatments. The results are in the range of the planned dose, within the combined relative uncertainty, demonstrating that the treatment-planning system compensates for the effects caused by the presence of femur and hip metal prostheses

  9. Accuracy of dose planning for prostate radiotherapy in the presence of metallic implants evaluated by electron spin resonance dosimetry

    Energy Technology Data Exchange (ETDEWEB)

    Alves, G.G. [Departamento de Física, Faculdade de Filosofia, Ciências e Letras de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, SP (Brazil); Kinoshita, A. [Departamento de Física, Faculdade de Filosofia, Ciências e Letras de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, SP (Brazil); Universidade Sagrado Coração, Bauru, SP (Brazil); Oliveira, H.F. de; Guimarães, F.S.; Amaral, L.L. [Serviço de Radioterapia, Hospital das Clínicas, Faculdade de Medicina de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, SP (Brazil); Baffa, O. [Departamento de Física, Faculdade de Filosofia, Ciências e Letras de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, SP (Brazil)

    2015-05-26

    Radiotherapy is one of the main approaches to cure prostate cancer, and its success depends on the accuracy of dose planning. A complicating factor is the presence of a metallic prosthesis in the femur and pelvis, which is becoming more common in elderly populations. The goal of this work was to perform dose measurements to check the accuracy of radiotherapy treatment planning under these complicated conditions. To accomplish this, a scale phantom of an adult pelvic region was used with alanine dosimeters inserted in the prostate region. This phantom was irradiated according to the planned treatment under the following three conditions: with two metallic prostheses in the region of the femur head, with only one prosthesis, and without any prostheses. The combined relative standard uncertainty of dose measurement by electron spin resonance (ESR)/alanine was 5.05%, whereas the combined relative standard uncertainty of the applied dose was 3.35%, resulting in a combined relative standard uncertainty of the whole process of 6.06%. The ESR dosimetry indicated that there was no difference (P>0.05, ANOVA) in dosage between the planned dose and treatments. The results are in the range of the planned dose, within the combined relative uncertainty, demonstrating that the treatment-planning system compensates for the effects caused by the presence of femur and hip metal prostheses.

  10. Personalized Monte Carlo dosimetry for the planning and evaluation of internal radiotherapy treatments: development and application to selective internal radiotherapy (SIRT)

    International Nuclear Information System (INIS)

    Petitguillaume, Alice

    2014-01-01

    Medical techniques in full expansion arousing high therapeutic expectations, targeted radionuclide therapies (TRT) consist of administering a radiopharmaceutical to selectively treat tumors. Nowadays, the activity injected to the patient is generally standardized. However, in order to establish robust dose-effect relationships and to optimize treatments while sparing healthy tissues at best, a personalized dosimetry must be performed, just like actual clinical practice in external beam radiotherapy. In that context, this PhD main objective was to develop, using the OEDIPE software, a methodology for personalized dosimetry based on direct Monte Carlo calculations. The developed method enables to calculate the tridimensional distribution of absorbed doses depending on the patient anatomy, defined from CT or MRI data, and on the patient-specific activity biodistribution, defined from SPECT or PET data. Radiobiological aspects, such as differences in radiosensitivities and repair time constants between tumoral and healthy tissues, have also been integrated through the linear-quadratic model. This methodology has been applied to the selective internal radiation therapy (SIRT) which consists in the injection of 90 Y-microspheres to selectively treat unresectable hepatic cancers. Distributions of absorbed doses and biologically effective doses (BED) along with the equivalent uniform biologically effective doses (EUD) to hepatic lesions have been calculated from 99m Tc-MAA activity distributions obtained during the evaluation step for 18 patients treated at Hopital Europeen Georges Pompidou. Those results have been compared to classical methods used in clinics and the interest of accurate and personalized dosimetry for treatment planning has been investigated. On the one hand, the possibility to increase the activity in a personalized way has been highlighted with the calculation of the maximal activity that could be injected to the patient while meeting tolerance criteria

  11. 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)

  12. Statistical process control applied to intensity modulated radiotherapy pretreatment controls with portal dosimetry;Maitrise statistique des processus appliquee aux controles avant traitement par dosimetrie portale en radiotherapie conformationnelle avec modulation d'intensite

    Energy Technology Data Exchange (ETDEWEB)

    Villani, N.; Noel, A. [Laboratoire de recherche en radiophysique, CRAN UMR 7039, Nancy universite-CNRS, 54 - Vandoeuvre-les-Nancy (France); Villani, N.; Gerard, K.; Marchesi, V.; Huger, S.; Noel, A. [Departement de radiophysique, centre Alexis-Vautrin, 54 - Vandoeuvre-les-Nancy (France); Francois, P. [Institut Curie, 75 - Paris (France)

    2010-06-15

    Purpose The first purpose of this study was to illustrate the contribution of statistical process control for a better security in intensity modulated radiotherapy (I.M.R.T.) treatments. This improvement is possible by controlling the dose delivery process, characterized by pretreatment quality control results. So, it is necessary to put under control portal dosimetry measurements (currently, the ionisation chamber measurements were already monitored by statistical process control thanks to statistical process control tools). The second objective was to state whether it is possible to substitute ionisation chamber with portal dosimetry in order to optimize time devoted to pretreatment quality control. Patients and methods At Alexis-Vautrin center, pretreatment quality controls in I.M.R.T. for prostate and head and neck treatments were performed for each beam of each patient. These controls were made with an ionisation chamber, which is the reference detector for the absolute dose measurement, and with portal dosimetry for the verification of dose distribution. Statistical process control is a statistical analysis method, coming from industry, used to control and improve the studied process quality. It uses graphic tools as control maps to follow-up process, warning the operator in case of failure, and quantitative tools to evaluate the process toward its ability to respect guidelines: this is the capability study. The study was performed on 450 head and neck beams and on 100 prostate beams. Results Control charts, showing drifts, both slow and weak, and also both strong and fast, of mean and standard deviation have been established and have shown special cause introduced (manual shift of the leaf gap of the multi-leaf collimator). Correlation between dose measured at one point, given with the E.P.I.D. and the ionisation chamber has been evaluated at more than 97% and disagreement cases between the two measurements were identified. Conclusion The study allowed to

  13. TU-E-201-03: Eye Lens Dosimetry in Radiotherapy Using Contact Lens-Shaped Applicator

    Energy Technology Data Exchange (ETDEWEB)

    Park, J. [Seoul National University Hospital (Korea, Republic of)

    2015-06-15

    . These actions should be considered when they are consistent with the clinical task and patient anatomy. Learning Objectives: To become familiar with method of eye dose estimation for patient in specific situation of brain perfusion CT To become familiar with level of eye lens radiation doses in patients undergoing brain perfusion MDCT To understand methods for reducing eye lens dose to patient Jong Min Park, Department of Radiation Oncology, Seoul National University Hospital, Seoul, Korea Eye lens dosimetry in radiotherapy using contact lens-shaped applicator Dose calculation accuracy of commercial treatment planning systems is relatively low at shallow depths. Therefore, in-vivo measurements are often performed in the clinic to verify delivered doses to eye lens which are located at shallow depth. Current in-vivo dosimetry for eye lens during radiotherapy is generally performed with small in-vivo dosimeters on the surface of patient eyelid. Since this procedure potentially contains considerable uncertainty, a contact lens-shaped applicator made of acrylic (lens applicator) was developed for in-vivo measurements of eye lens dose during radiotherapy to reduce uncertainty. The lens applicator allows the insertion of commercially available metal oxide semiconductor field effect transistor (MOSFET) dosimeters. Computed tomography (CT) images of an anthropomorphic phantom with and without the lens applicator were acquired. A total of 20 VMAT plans were delivered to an anthropomorphic phantom and the doses with the lens applicator and the doses at the surface of the eyelid were measured using both micro and standard MOSFET dosimeters. The differences in measured dose at the surface of the eyelid from the calculated lens dose were acquired. The differences between the measured and the calculated doses at the lens applicator, as well as the differences between the measured and the calculated doses at the surface of the eyelid were acquired. The statistical significance of the

  14. Computational voxel phantom, associated to anthropometric and anthropomorphic real phantom for dosimetry in human male pelvis radiotherapy

    International Nuclear Information System (INIS)

    Silva, Cleuza Helena Teixeira; Campos, Tarcisio Passos Ribeiro de

    2005-01-01

    This paper addresses a computational model of voxels through MCNP5 Code and the experimental development of an anthropometric and anthropomorphic phantom for dosimetry in human male pelvis brachytherapy focusing prostatic tumors. For elaboration of the computational model of the human male pelvis, anatomical section images from the Visible Man Project were applied. Such selected and digital images were associated to a numeric representation, one for each section. Such computational representation of the anatomical sections was transformed into a bi-dimensional mesh of equivalent tissue. The group of bidimensional meshes was concatenated forming the three-dimensional model of voxels to be used by the MCNP5 code. In association to the anatomical information, data from the density and chemical composition of the basic elements, representatives of the organs and involved tissues, were setup in a material database for the MCNP-5. The model will be applied for dosimetric evaluations in situations of irradiation of the human masculine pelvis. Such 3D model of voxel is associated to the code of transport of particles MCNP5, allowing future simulations. It was also developed the construction of human masculine pelvis phantom, based on anthropometric and anthropomorphic dates and in the use of representative equivalent tissues of the skin, fatty, muscular and glandular tissue, as well as the bony structure.This part of work was developed in stages, being built the bony cast first, later the muscular structures and internal organs. They were then jointly mounted and inserted in the skin cast. The representative component of the fatty tissue was incorporate and accomplished the final retouchings in the skin. The final result represents the development of two important essential tools for elaboration of computational and experimental dosimetry. Thus, it is possible its use in calibrations of pre-existent protocols in radiotherapy, as well as for tests of new protocols, besides

  15. Characterisation of sensitive Ge-doped silica flat fibre-based thermoluminescence detectors for high resolution radiotherapy dosimetry

    Science.gov (United States)

    Rahim, A. R. Abdul; Zahaimi, N. A.; Zin, H. M.; Bradley, D. A.; Mahdiraji, G. A.; Rahman, A. T. Abdul

    2017-05-01

    Present study focuses on characterisation of SiO2 optical fibers as a potential thermoluminescence (TL) system for radiation therapy dosimetry. Irradiations were made using 6 MV photon beams from a linear accelerator. Flat SiO2 optical fibers of various dimensions with 8% concentration of germanium doped were used. The dimensions of the flat fibers were 270×60 µm, 360×73 µm, 100×510 µm and 160×750 µm. Flat SiO2 optical fibers were characterised for TL dose response in terms of linearity, sensitivity, fading and reproducibility. The uncertainty measured was ±1 standard error of the mean and the coefficient variation was within ±4%, as required for clinical radiotherapy dosimetry. Results shown a good distribution of TL response measured by flat SiO2 optical fibers with uncertainties less than 4%. Linearity of TL comes out with a coefficient of determination (r2) of each fibers that is better than 99% which resulted in high percentage of confidence level. The loss of TL response due to fading, for photon irradiation at fixed energy and constant dose was found to be (20.4 ± 0.2)% over a post irradiation period of 30 days. The TL fading well, showing rapid loss in the first seven (7) days (17.8 ± 0.2)% followed by a more linear like loss subsequently the following day (3.2 ± 0.2)%. A perfect selection of fibers can enhance the accuracy of radiation dosimeter in order for better determination and measurement of radiation doses with a linear response over wide range therapeutic dose.

  16. Recent advances in Optical Computed Tomography (OCT) imaging system for three dimensional (3D) radiotherapy dosimetry

    Science.gov (United States)

    Rahman, Ahmad Taufek Abdul; Farah Rosli, Nurul; Zain, Shafirah Mohd; Zin, Hafiz M.

    2018-01-01

    Radiotherapy delivery techniques for cancer treatment are becoming more complex and highly focused, to enable accurate radiation dose delivery to the cancerous tissue and minimum dose to the healthy tissue adjacent to tumour. Instrument to verify the complex dose delivery in radiotherapy such as optical computed tomography (OCT) measures the dose from a three-dimensional (3D) radiochromic dosimeter to ensure the accuracy of the radiotherapy beam delivery to the patient. OCT measures the optical density in radiochromic material that changes predictably upon exposure to radiotherapy beams. OCT systems have been developed using a photodiode and charged coupled device (CCD) as the detector. The existing OCT imaging systems have limitation in terms of the accuracy and the speed of the measurement. Advances in on-pixel intelligence CMOS image sensor (CIS) will be exploited in this work to replace current detector in OCT imaging systems. CIS is capable of on-pixel signal processing at a very fast imaging speed (over several hundred images per second) that will allow improvement in the 3D measurement of the optical density. The paper will review 3D radiochromic dosimeters and OCT systems developed and discuss how CMOS based OCT imaging will provide accurate and fast optical density measurements in 3D. The paper will also discuss the configuration of the CMOS based OCT developed in this work and how it may improve the existing OCT system.

  17. Quantification of fat fraction in lumbar vertebrae: correlation with age and implications for bone marrow dosimetry in molecular radiotherapy

    Science.gov (United States)

    Salas-Ramirez, Maikol; Tran-Gia, Johannes; Kesenheimer, Christian; Weng, Andreas Max; Kosmala, Aleksander; Heidemeier, Anke; Köstler, Herbert; Lassmann, Michael

    2018-01-01

    Absorbed dose to active bone marrow is a predictor of hematological toxicity in molecular radiotherapy. Due to the complex composition of bone marrow tissue, the necessity to improve the personalized dosimetry has led to the application of non-conventional imaging methods in nuclear medicine. The aim of this study is to apply magnetic resonance imaging (MRI) for quantification of the fat fraction in lumbar vertebrae and to analyze its implications for bone marrow dosimetry. First, a highly accelerated two-point Dixon MRI sequence for fat-water separation was validated in a 3T system against the magnetic resonance spectroscopy (MRS) gold standard. The validation was performed in a fat-water phantom composed of 11 vials with different fat fractions between 0% and 100%, and subsequently repeated in the lumbar vertebrae of three healthy volunteers. Finally, a retrospective study was performed by analyzing the fat fraction in five lumbar vertebrae of 44 patients scanned with the two-point Dixon sequence. The two-point Dixon phantom acquisition showed a good agreement (maximum difference  =  2.9%) between the nominal fat fraction and MRS. In the volunteers, a statistical analysis showed a non-significant difference (p  =  0.19) between MRI and MRS. In the patients, gender-specific linear fits for female and male data indicated that the age-dependent marrow conversion (red  →  yellow marrow) is slower in males (0.3% per year) than in females (0.5% per year). Lastly, the fat fraction values showed a considerable variability in patients of similar ages and the same gender. Two-point Dixon MRI enables a non-invasive and spatially resolved quantification of the fat fraction in bone marrow. Our study provides important evidence on the differences in marrow conversion between females and males. In addition, differences were observed in the cellularity values of the International Commission on Radiological Protection (ICRP) reference man (0.7) and the

  18. MRI gel dosimetry for verification of mono-isocentric junction doses in head and neck radiotherapy

    International Nuclear Information System (INIS)

    Back, S.A.J.; Jayasekera, P.M.; Lepage, M.; Baldock, C.; Menzies, N.; Back, P.

    2000-01-01

    Full text: The use of independent collimators in the abutment of two adjacent treatment volumes, as in head and neck radiation treatments, consists typically of positioning the collimator rotation axis (CRA) at the junction of the volumes, and offsetting each field by its half-field width. This has the effect of positioning one of the collimator jaws at the CRA for each field. However, misalignment of the jaws can lead to variations in dose uniformity in the junction region. We have used gel dosimetry to measure junction doses in three dimensions. PAG gel MRI was used to investigate junction dosimetry for a mono-isocentriic treatment of two orthogonal pairs of opposed (ant/post and lateral) 6 MV x-ray beams. PAG gels in an 11cm diameter cylindrical gel phantom were imaged using a Siemens Vision 1.5 T MRI. The exposures were made using a Philips SL 20 linear accelerator with independent jaws that were known to overlap at the isocentre for sequential abutting offset (within manufacturer's specifications for symmetric fields). X-Omat V films were exposed in mono-directional beams, and optically scanned for comparison. Measurements of off-axis ratios and of relative depth profiles using gel MRI and perpendicular film were in excellent agreement with each other. Measurements through the multi-directional junction at the isocentre are illustrated in the graph, for orthogonal planes centred at the isocentre of the neck phantom. They demonstrate a minimum dose of 75 % of that of the adjacent 'treatment' regions, which agrees closely with the results measured (72%) in the mono-directional case with film. We conclude that this measurement confirms that junction dosimetry at the isocentre measured with perpendicular film for a single direction is a good approximation to the situation in multiple directions. Copyright (2000) Australasian College of Physical Scientists and Engineers in Medicine

  19. Radiotherapy physics

    International Nuclear Information System (INIS)

    Chen, G.T.Y.; Collier, J.M.; Lyman, J.T.; Pitluck, S.

    1982-01-01

    The Radiotherapy Physics Group works on the physical and biophysical aspects of charged particle radiotherapy. Our activities include the development of isosurvival beams (beams of uniform biological effect), computerized treatment planning development for charged particle radiotherapy, design of compensation to shape dose distributions, and development of dosimetry techniques to verify planned irradiations in both phantoms and patients

  20. Test Program Set (TPS) Lab

    Data.gov (United States)

    Federal Laboratory Consortium — The ARDEC TPS Laboratory provides an organic Test Program Set (TPS) development, maintenance, and life cycle management capability for DoD LCMC materiel developers....

  1. The influence of neutron contamination on dosimetry in external photon beam radiotherapy.

    Science.gov (United States)

    Horst, Felix; Czarnecki, Damian; Zink, Klemens

    2015-11-01

    Photon fields with energies above ∼7 MeV are contaminated by neutrons due to photonuclear reactions. Their influence on dosimetry-although considered to be very low-is widely unexplored. In this work, Monte Carlo based investigations into this issue performed with fluka and egsnrc are presented. A typical Linac head in 18 MV-X mode was modeled equivalently within both codes. egsnrc was used for the photon and fluka for the neutron production and transport simulation. Water depth dose profiles and the response of different detectors (Farmer chamber, TLD-100, TLD-600H, and TLD-700H chip) in five representative depths were simulated and the neutrons' impact (neutron absorbed dose relative to photon absorbed dose) was calculated. To take account of the neutrons' influence, a theoretically required correction factor was defined and calculated for five representative water depths. The neutrons' impact on the absorbed dose to water was found to be below 0.1% for all depths and their impact on the response of the Farmer chamber and the TLD-700H chip was found to be even less. For the TLD-100 and the TLD-600H chip it was found to be up to 0.3% and 0.7%, respectively. The theoretical correction factors to be applied to absorbed dose to water values measured with these four detectors in a depth different from the reference/calibration depth were calculated and found to be below 0.05% for the Farmer chamber and the TLD-700H chip, but up to 0.15% and 0.35% for the TLD-100 and TLD-600H chips, respectively. In thermoluminescence dosimetry the neutrons' influence (and therefore the additional inaccuracy in measurement) was found to be higher for TLD materials whose 6Li fraction is high, such as TLD-100 and TLD-600H, resulting from the thermal neutron capture reaction on 6Li. The impact of photoneutrons on the absorbed dose to water and on the response of a typical ionization chamber as well as three different types of TLD chips was quantified and was as expected found to be very

  2. In vivo thermoluminescent dosimetry on the radiotherapy of limphomas, esophageal and uterine tumour

    International Nuclear Information System (INIS)

    Morales, F.C.

    1982-01-01

    A comparative study between dose distribution in pre-selected tumoral plans was established through measurements with thermoluminescent dosimeters and calculations based on 'scatter-air-ratios' properties, isodose curves and collected data. Clinic dosimetry was performed 'in vivo' with LiF dosimeters (TLD-100) and LiF Teflon (1 mm theta, 6 mm lenght). Patients with Hodgkin's disease, carcinoma of the esophagus and of the uterine cervix were selected. Telecobaltherapy was used for these groups of neoplasic conditions. (M.A.C.) [pt

  3. 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

  4. Internal dosimetry for blood vessels radiotherapy; Dosimetria interna para terapia com radiacao em vasos sanguineos

    Energy Technology Data Exchange (ETDEWEB)

    Campos, Laelia Pumilla Botelho [Pernambuco Univ., Recife, PE (Brazil). Dept. de Energia Nuclear] E-mail: lpbcampos@uol.com.br; Stabin, Michael Gregory [Vanderbilt Univ., Nashville, TN (United States). Dept. of Radiology and Radiological Sciences] E-mail: Michael.Stabin@mcmail.vanderbilt.edu

    2001-07-01

    Among the cardiovascular diseases, the most common is acute myocardial infarction, which occurs because of the occlusion of one or more coronary arteries. Balloon angioplasty has been a popular treatment which is less invasive than surgeries involving revascularization of the myocardium, thus promising a better quality of life for patients. Unfortunately, the rate of restenosis (re-closing of the vessel) after balloon angioplasty is high (approximately 30-50% within the first year after treatment). Known as Intravascular Brachytherapy, the technique has been used with several radiation sources, and researchers have obtained success in decreasing the rate of restenosis. In order to study the radiation dosimetry in the patient and radiological protection for this therapy, radiation dose distributions for monoenergetic electrons and photons (at nine discrete energies) were calculated for blood vessels of diameter 0.15, 0.30 and 0.45 cm with balloon and wire sources using the radiation transport code MCNP4B. Specific calculations were carried out for several radionuclides. Advantages and disadvantages of the radionuclides and source geometries are discussed and the dosimetry developed here will aid in the realization of the benefits obtained in patients. (author)

  5. Biological dosimetry for the reconstruction of doses absorbed during accidents in radiotherapy

    International Nuclear Information System (INIS)

    Wojcik, A.; Stephan, G.; Sommer, S.; Urbanik, W.; Kukolowicz, P.; Kuszewski, T.; Gozdz, S.

    2002-01-01

    Medical radiation represents by far the largest man-made source of radiation exposure. The recent accident in a radiotherapy unit in Bialystok, Poland, clearly showed the necessity to develop biological methods allowing a reconstruction of the absorbed dose in case of an accidental exposure. We are currently analysing the frequencies of micronuclei in lymphocytes of patients undergoing radiotherapy of tumors localized in different parts of the body. The aim of the studies in the setting up to appropriate calibration curves with the help of which a dose absorbed during an accident could be estimated. In addition, the applicability of such calibration curves for quality assurance of teleradiotherapy will be considered. In order to calculate the expected frequencies of aberrations and micronuclei in lymphocytes of patients undergoing teleradiotherapy a mathematical model was developed. The modeled dose-response curves agree well with the majority of published experimental results and will serve as a basis for ongoing studies. (author)

  6. Urethral dosimetry constraints in 125I permanent prostate brachytherapy used as boost to external radiotherapy

    International Nuclear Information System (INIS)

    Lliso, F.; Perez-Calatayud, J.; Carmona, V.; Guirado, D.; Munoz, M.; Richart, J.; Ballester, F.; Granero, D.; Rodriguez, S.; Tormo, A.; Santos, M.

    2010-01-01

    With 125I monotherapy in permanent brachytherapy implants, the recommendation is to deliver to the urethra less than 150% of the prescribed dose, 145 Gy, that is a limit of 217.5 Gy. However, there are not recommendations in the case of the brachytherapy boost. At our hospitals, permanent brachytherapy implants are used as a 108 Gy boost in intermediate risk patients with prostate carcinoma, which have undergone an external beam radiotherapy course ranging between 45 and 50.4 Gy. The purpose of this work is to present a simple radiobiologically-based analysis performed in order to obtain the urethral dose limit in permanent prostate brachytherapy boost. The linear-quadratic model has been used to determine the biologically effective dose, analysing the results for different dose/fraction, t1/2 and a/b values. Assuming 46 Gy delivered by external beam radiotherapy, it is found that a limit value of 145 Gy, corresponding to the isodose level of 135% of the prescribed dose, is adequate. The results for a ten patients sample are shown in order to illustrate the values that are obtained in clinical practice. In conclusion, we present the method employed to find the urethral dose limit in the case of the combination of external beam radiotherapy and permanent 125I seeds brachytherapy boost implants (Author).

  7. SIMULASI AUDIT DOSIMETRI TREATMENT PLANNING SYSTEM FOTON SINAR-X 6 MV MULTICENTER RADIOTERAPI

    OpenAIRE

    Suwandi, Suwandi; Wibowo, Wahyu Edy; Pawiro, Supriyanto Ardjo

    2016-01-01

    TPS is an important modality determining radiotherapy outcome. According to accident and incident international reporting database in radiotherapy, TPS related occurences are among the main sources of errors. TPS requires input beam data obtained through commissioning. The errors at this step results in systematic errors. The purpose of this study is to verify TPS dosimetric to determine the deviation between the dose calculated by TPS and measured dose in phantom representing the dose receiv...

  8. 2-D dosimetry of a proton radiotherapy beam using large-area LiF:Mg,Cu,P TL detectors

    Energy Technology Data Exchange (ETDEWEB)

    Czopyk, L. [Institute of Nuclear Physics Polish Academy of Sciences, Krakow (Poland)], E-mail: Lukasz.Czopyk@ifj.edu.pl; Cirrone, G.A.P.; Cuttone, G. [National Institute of Nuclear Physics, Catania (Italy); Klosowski, M.; Olko, P.; Sroka, U. [Institute of Nuclear Physics Polish Academy of Sciences, Krakow (Poland); Waligorski, M.P.R. [Institute of Nuclear Physics Polish Academy of Sciences, Krakow (Poland); Centre of Oncology Maria Sklodowska-Curie Memorial Institute Krakow Branch, Krakow (Poland)

    2008-02-15

    A two-dimensional (2-D) thermoluminescence (TL) dosimetry system, consisting of LiF:Mg,Cu,P (MCP-N)-based TL foils and a TLD reader equipped with a CCD camera, was developed at the Institute of Nuclear Physics (IFJ PAN) in Krakow, Poland. We applied this system to verify 2-D dose distributions in the 62 MeV proton ocular radiotherapy beam at INFN, Catania. TL foils placed inside a specially designed PMMA eye phantom were irradiated and read out to determine 40x40mm{sup 2} planar (X-Y and X-Z) dose distributions for doses up to 16 Gy. Dose and energy response for LiF:Mg,Cu,P were calculated using the one-hit detector microdosimetric model and applied to correct the detector response. TLD-measured and MCNPX-calculated distal ranges agreed to within 0.3 mm, while TLD-measured transverse beam cross-sections were about 0.8 mm wider than those calculated using the MCNPX Monte Carlo code.

  9. EPID-based in vivo dosimetry for stereotactic body radiotherapy of non-small cell lung tumors: Initial clinical experience.

    Science.gov (United States)

    Consorti, R; Fidanzio, A; Brainovich, V; Mangiacotti, F; De Spirito, M; Mirri, M A; Petrucci, A

    2017-10-01

    EPID-based in vivo dosimetry (IVD) has been implemented for stereotactic body radiotherapy treatments of non-small cell lung cancer to check both isocenter dose and the treatment reproducibility comparing EPID portal images. 15 patients with lung tumors of small dimensions and treated with volumetric modulated arc therapy were enrolled for this initial experience. IVD tests supplied ratios R between in vivo reconstructed and planned isocenter doses. Moreover a γ-like analysis between daily EPID portal images and a reference one, in terms of percentage of points with γ-value smaller than 1, P γlevels of 5% for R ratio, P γlevel, and an average P γ90%. Paradigmatic discrepancies were observed in three patients: a set-up error and a patient morphological change were identified thanks to CBCT image analysis whereas the third discrepancy was not fully justified. This procedure can provide improved patient safety as well as a first step to integrate IVD and CBCT dose recalculation. Copyright © 2017 Associazione Italiana di Fisica Medica. Published by Elsevier Ltd. All rights reserved.

  10. Dosimetry for synchrotron stereotactic radiotherapy: Monte Carlo simulations and radiosensitive gels

    International Nuclear Information System (INIS)

    Boudou, C.

    2006-09-01

    High grade gliomas are extremely aggressive brain tumours. Specific techniques combining the presence of high atomic number elements within the tumour to an irradiation with a low x-rays (below 100 keV) beam from a synchrotron source were proposed. For the sake of clinical trials, the use of treatment planning system has to be foreseen as well as tailored dosimetry protocols. Objectives of this thesis work were (1) the development of a dose calculation tools based on Monte Carlo code for particles transport and (2) the implementation of an experimental method for the three dimensional verification of the dose delivered. The dosimetric tool is an interface between tomography images from patient or sample and the M.C.N.P.X. general purpose code. Besides, dose distributions were measured through a radiosensitive polymer gel, providing acceptable results compared to calculations

  11. In vivo dosimetry in intraoperative electron radiotherapy. microMOSFETs, radiochromic films and a general-purpose linac

    Energy Technology Data Exchange (ETDEWEB)

    Lopez-Tarjuelo, Juan; Marco-Blancas, Noelia de; Santos-Serra, Agustin; Quiros-Higueras, Juan David [Consorcio Hospitalario Provincial de Castellon, Servicio de Radiofisica y Proteccion Radiologica, Castellon de la Plana (Spain); Bouche-Babiloni, Ana; Morillo-Macias, Virginia; Ferrer-Albiach, Carlos [Consorcio Hospitalario Provincial de Castellon, Servicio de Oncologia Radioterapica, Castellon de la Plana (Spain)

    2014-11-15

    In vivo dosimetry is desirable for the verification, recording, and eventual correction of treatment in intraoperative electron radiotherapy (IOERT). Our aim is to share our experience of metal oxide semiconductor field-effect transistors (MOSFETs) and radiochromic films with patients undergoing IOERT using a general-purpose linac. We used MOSFETs inserted into sterile bronchus catheters and radiochromic films that were cut, digitized, and sterilized by means of gas plasma. In all, 59 measurements were taken from 27 patients involving 15 primary tumors (seven breast and eight non-breast tumors) and 12 relapses. Data were subjected to an outliers' analysis and classified according to their compatibility with the relevant doses. Associations were sought regarding the type of detector, breast and non-breast irradiation, and the radiation oncologist's assessment of the difficulty of detector placement. At the same time, 19 measurements were carried out at the tumor bed with both detectors. MOSFET measurements (D = 93.5 %, s{sub D} = 6.5 %) were not significantly shifted from film measurements (D = 96.0 %, s{sub D} = 5.5 %; p = 0.109), and no associations were found (p = 0.526, p = 0.295, and p = 0.501, respectively). As regards measurements performed at the tumor bed with both detectors, MOSFET measurements (D = 95.0 %, s{sub D} = 5.4 %) were not significantly shifted from film measurements (D = 96.4 %, s{sub D} = 5.0 %; p = 0.363). In vivo dosimetry can produce satisfactory results at every studied location with a general-purpose linac. Detector choice should depend on user factors, not on the detector performance itself. Surgical team collaboration is crucial to success. (orig.) [German] Die In-vivo-Dosimetrie ist wuenschenswert fuer die Ueberpruefung, Registrierung und die eventuelle Korrektur der Behandlungen in der IOERT (''Intraoperative Electron Radiation Therapy''). Unser Ziel ist die Veroeffentlichung unserer Erfahrungen beim

  12. Effects of the Metallic Port in Tissue Expanders on Dose Distribution in Postmastectomy Radiotherapy: A Tridimensional Experimental Model of Dosimetry in Breast Reconstruction.

    Science.gov (United States)

    da Silva, Marcelo Felix; de Oliveira, Harley Francisco; Borges, Leandro Frederich; Carrara, Helio Humberto Angotti; Farina, Jayme Adriano

    2018-01-01

    The purpose of this research was to develop an experimental model of dosimetry using a breast phantom and evaluate the effects of the metallic port in tissue expanders on dose distribution in postmastectomy radiotherapy. Dose distribution was assessed using an experimental acrylic dosimetry simulator in the absence and presence of a metallic disc (MD), which is similar to that used in tissue expanders containing a magnetic port, by collecting coronal and sagittal radiochromic films. Dosimetry film analysis did not show any changes in dose distribution, except for a MD shadow in the sagittal film where the dose distribution rate was on average 14% lower than in other areas. This model very closely resembled actual breast reconstruction with a tissue expander containing a magnetic port. Scattering or attenuation of the irradiation dose due to interference of the MD was not evident in areas that could jeopardize the effectiveness of radiation therapy. Therefore, the presence of the MD inside the tissue expander does not likely have an impact on radiotherapy effectiveness during immediate breast reconstruction.

  13. Computer-assisted dosimetry in the radiotherapy of cancer of the cervix

    International Nuclear Information System (INIS)

    Calaguas, M.J.C.; Rodriguez, L.V.; Vito Cruz, E.Q.; Legaspi, G.C.; De Luna, R.M.; Hermoso, T.M.; Razon, E.C.; Madrid, E.T.; Viray, R.G.

    1992-01-01

    Cancer of the cervix is the third leading cause of cancer in the Philippines. The Department of Radiotherapy of the Jose R. Reyes Memorial Medical Center has participated in the Regional Coordinated Research project sponsored by the International Atomic Energy Agency (IAEA) to undertake a study to compare computer treatment planning and manual calculations in radiotherapy of the cancer of the cervix; and to perform actual measurements on bladder and rectal points using TLDs. Twenty-seven patients with Stage II-B to III-B were included in the study. External beam teletherapy of 40 Gy without shielding for 4 weeks and 50 Gy with blocks plus brachytherapy of 20-40 Gy were given using LDR or HDR machine. Point A, bladder and rectal points were defined following ICRU 38 recommendations. The results showed dose calculations between commercially available computers and IAEA - provided computers agree to within 20%. Results of TLD measurement in bladder and rectum have shown wide range of variation. (author). 3 refs.; 4 tabs.; 8 figs

  14. In vivo dosimetry in intraoperative electron radiotherapy: microMOSFETs, radiochromic films and a general-purpose linac.

    Science.gov (United States)

    López-Tarjuelo, Juan; Bouché-Babiloni, Ana; Morillo-Macías, Virginia; de Marco-Blancas, Noelia; Santos-Serra, Agustín; Quirós-Higueras, Juan David; Ferrer-Albiach, Carlos

    2014-10-01

    In vivo dosimetry is desirable for the verification, recording, and eventual correction of treatment in intraoperative electron radiotherapy (IOERT). Our aim is to share our experience of metal oxide semiconductor field-effect transistors (MOSFETs) and radiochromic films with patients undergoing IOERT using a general-purpose linac. We used MOSFETs inserted into sterile bronchus catheters and radiochromic films that were cut, digitized, and sterilized by means of gas plasma. In all, 59 measurements were taken from 27 patients involving 15 primary tumors (seven breast and eight non-breast tumors) and 12 relapses. Data were subjected to an outliers' analysis and classified according to their compatibility with the relevant doses. Associations were sought regarding the type of detector, breast and non-breast irradiation, and the radiation oncologist's assessment of the difficulty of detector placement. At the same time, 19 measurements were carried out at the tumor bed with both detectors. MOSFET measurements ([Formula: see text]  = 93.5 %, sD  =  6.5 %) were not significantly shifted from film measurements ([Formula: see text]  =  96.0 %, sD  =  5.5 %; p  =  0.109), and no associations were found (p = 0.526, p = 0.295,  and p = 0.501, respectively). As regards measurements performed at the tumor bed with both detectors, MOSFET measurements ([Formula: see text]  =  95.0 %, sD  =  5.4 % were not significantly shifted from film measurements ([Formula: see text]  =  96.4 %, sD  =  5.0 %; p  =  0.363). In vivo dosimetry can produce satisfactory results at every studied location with a general-purpose linac. Detector choice should depend on user factors, not on the detector performance itself. Surgical team collaboration is crucial to success.

  15. A simple method to back-project isocenter dose of radiotherapy treatments using EPID transit dosimetry

    Energy Technology Data Exchange (ETDEWEB)

    Silveira, T.B.; Cerbaro, B.Q.; Rosa, L.A.R. da, E-mail: thiago.fisimed@gmail.com, E-mail: tbsilveira@inca.gov.br [Instituto de Radioproteção e Dosimetria (IRD/CNEN-RJ), Rio de Janeiro - RJ (Brazil)

    2017-07-01

    The aim of this work was to implement a simple algorithm to evaluate isocenter dose in a phantom using the back-projected transmitted dose acquired using an Electronic Portal Imaging Device (EPID) available in a Varian Trilogy accelerator with two nominal 6 and 10 MV photon beams. This algorithm was developed in MATLAB language, to calibrate EPID measured dose in absolute dose, using a deconvolution process, and to incorporate all scattering and attenuation contributions due to photon interactions with phantom. Modeling process was simplified by using empirical curve adjustments to describe the contribution of scattering and attenuation effects. The implemented algorithm and method were validated employing 19 patient treatment plans with 104 clinical irradiation fields projected on the phantom used. Results for EPID absolute dose calibration by deconvolution have showed percent deviations lower than 1%. Final method validation presented average percent deviations between isocenter doses calculated by back-projection and isocenter doses determined with ionization chamber of 1,86% (SD of 1,00%) and -0,94% (SD of 0,61%) for 6 and 10 MV, respectively. Normalized field by field analysis showed deviations smaller than 2% for 89% of all data for 6 MV beams and 94% for 10 MV beams. It was concluded that the proposed algorithm possesses sufficient accuracy to be used for in vivo dosimetry, being sensitive to detect dose delivery errors bigger than 3-4% for conformal and intensity modulated radiation therapy techniques. (author)

  16. 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)

  17. Real-time in vivo luminescence dosimetry in radiotherapy and mammography using Al2O3:C

    DEFF Research Database (Denmark)

    Aznar, Marianne

    2005-01-01

    treatments (such as intensity-modulated radiation therapy) indicate that the RL/OSL dosimetry system canreliably measure the absorbed dose within 2%. The real-time RL signal also enables an individual dose assessment from each field. The RL/OSL dosimetry system was also used during mammography examinations......New treatment and clinical imaging techniques have created a need for accurate and practical in vivo dosimeters in radiation medicine. This work describes the development of a new optical-fiber radiation dosimeter system, based on radioluminescence (RL)and optically stimulated luminescence (OSL......) from carbon-doped aluminium oxide (Al2O3:C), for applications in radiotherapy and mammography. This system offers several features, such as a small detector, high sensitivity, real-time read-out, and the abilityto measure both dose rate and absorbed dose. Measurement protocols and algorithms...

  18. Thermoluminescent dosimetry applied to radiotherapy carried out around the Therac-20-Saturne linear accelerator

    International Nuclear Information System (INIS)

    Bennab, K.

    1984-10-01

    In the first part of this work, the physical and technical aspects necessary to a radiotherapy treatment planning elaboration are presented. These include the apparatus description as well as the measurements of the dosimetric quantities relative to the delivered beams. Since in-vivo measurements are very useful to optimise the treatment conditions, the second part deals with thermoluminescent dosimeters, their characteristics and their setting out such as they be used with maximum efficiency. In-vivo measurements carried out enabled us to estimate the delivered dose to a given tumor with a precision down to +-4%. The registered differences between the measured dose and the prescribed one made possible an appropriate corrective action. Because of the difficulties encountered with conventional dosimetric systems when used in narrow beam measurements, we have developed a new method making use of TL dosimeters. The results obtained will allow treatments of small volume tumors with the significant advantage of saving healthy surrounding tissues from irradiation

  19. Real-time in vivo luminescence dosimetry in radiotherapy and mammography using Al{sub 2}O{sub 3}:C

    Energy Technology Data Exchange (ETDEWEB)

    Aznar, M.C.

    2005-06-15

    New treatment and clinical imaging techniques have created a need for accurate and practical in vivo dosimeters in radiation medicine. This work describes the development of a new optical-fiber radiation dosimeter system, based on radioluminescence (RL) and optically stimulated luminescence (OSL) from carbon-doped aluminium oxide (Al2O3:C), for applications in radiotherapy and mammography. This system offers several features, such as a small detector, high sensitivity, real-time read-out, and the ability to measure both dose rate and absorbed dose. Measurement protocols and algorithms for the correction of responses were developed to enable a reliable absorbed dose assessment from the RL and OSL signals. At radiotherapy energies, the variation of the signal with beam parameters was smaller than 1% (1 SD). Treatment-like experiments in phantoms, and in vivo measurements during complex patient treatments (such as intensity-modulated radiation therapy) indicate that the RL/OSL dosimetry system can reliably measure the absorbed dose within 2%. The real-time RL signal also enables an individual dose assessment from each field. The RL/OSL dosimetry system was also used during mammography examinations. In such conditions, the reproducibility of the measurements showed to be around 3%. In vivo measurements on three patients showed that the presence of the RL/OSL probes did not degrade the diagnostic quality of the radiograph and that the system could be used to measure exit doses (i.e., absorbed doses on the inferior surface of the breast). A Monte Carlo study proved that the energy dependence of the RL/OSL system at these low energies could be reduced by optimizing the design of the probes. It is concluded that the new RL/OSL dosimetry system shows considerable potential for applications in both radiotherapy and mammography. (au)

  20. Improvements in the Tl dosimetry for Radiotherapy; Mejoras en la dosimetria Tl para Radioterapia

    Energy Technology Data Exchange (ETDEWEB)

    Bustos, S.; Velez, G.; Rubio, M. [CEPROCOR. Arenales 230 Juniors Cordoba 5000 (Argentina)

    1998-12-31

    The thermoluminescent dosimetry (TLD) in vivo has been demonstrated to be one of the most reliable for the control of radiotherapeutic treatments, but the delay in the response is the main disadvantage in its applicability. In this work are presented important improvements and it is demonstrated that maintaining the accuracy and reliability of the technique, it is possible to accelerate the response times at a few hours. To realize this work is utilized a lecturer Harshaw 4000, dosemeters LiF-TLD-100 chips (3.1 x 3.1 x 0.89 mm{sup 3}) and rods (1 x 1 x 6 mm{sup 3}). With the implementation of a glow curve analysis program developed in CIEMAT, its obtained a Tl peaks separation in such manner rapid and accurate, by that the thermal treatment of dosemeters may be reduced at one unique annealing pre-irradiation for 1 hr at 400 Centigrade. It is realized a periodical and individual calibration of the TLD and a study of the factors which influencing the ratio Tl signal-dose as linearity, correction by energy, directional response and pride of Tl signal. the results of this study are introducing in a calculation list specially designed and which allows to obtain absorbed dose by TLD starting of the dates (dosimetric peaks area) which appear of the glow curves analysis. The dose is obtained with an accuracy less than 5 %. The dosemeters already irradiated (in vivo) are analysed and informed in only four hours, allowing a greater control of the treatment and a correction of the possible errors for the next session, still in bi fractional treatments. The method implemented results thus accurate, rapid and reliable. (Author)

  1. In vivo dosimetry implementation using diodes at the national radiotherapy center of the Korle-Bu Teaching Hospital, Ghana

    International Nuclear Information System (INIS)

    Atuwo-Ampoh, V. D.

    2014-07-01

    Protocol for in vivo dosimetry using silicon diodes in radiotherapy department of the Kole-Bu Teaching Hospital is implemented. The diodes were calibrated using IAEA standards (TRS 389); correction factors were determined with solid water phantom and then implemented on patients.The phantom studies conducted demonstrated that the mean deviation (Δ± σ, %) between the measured and expected entrance dose was within 5% (0.34 ± 1.8%) deviation in almost all cases. The site measured with the diodes on patient included; pelvis (n=60), head and neck (H/N; n=13), breast (n=48) and other cases (n=13) with mean deviations (Δ±σ %) of 1.92± 4.05, 0.15 ± 4.0, 0.12 ± 4.20 and 1.66 ± 3.23 respectively. Results obtained from patient measurements were comparable to works published in the literature. An overall mean deviation of 1.02%±4.1 was observed (n=134). The percentage of measurement (N %) for which the deviation was within the 5% tolerance was 79.85%. About 3.73% of the total deviations were beyond 7%. However, two actions levels were adopted for this study as 5% and 7% for simple and tangential fields respectively in line with similar studies using diodes in Poland. The few major deviations that however were recorded can be attributed to sources of errors such as the wrong beam parameters as depth, wedges and the inability to precisely position the dosimeter in blocked and wedged fields. There is more room for reduction in the uncertainties associated with the measurement protocol developed by carefully limiting or avoiding all the errors. (au)

  2. Evaluation of plastic materials for range shifting, range compensation, and solid-phantom dosimetry in carbon-ion radiotherapy

    International Nuclear Information System (INIS)

    Kanematsu, Nobuyuki; Koba, Yusuke; Ogata, Risa

    2013-01-01

    Purpose: Beam range control is the essence of radiotherapy with heavy charged particles. In conventional broad-beam delivery, fine range adjustment is achieved by insertion of range shifting and compensating materials. In dosimetry, solid phantoms are often used for convenience. These materials should ideally be equivalent to water. In this study, the authors evaluated dosimetric water equivalence of four common plastics, high-density polyethylene (HDPE), polymethyl methacrylate (PMMA), polyethylene terephthalate (PET), and polyoxymethylene (POM). Methods: Using the Bethe formula for energy loss, the Gottschalk formula for multiple scattering, and the Sihver formula for nuclear interactions, the authors calculated the effective densities of the plastics for these interactions. The authors experimentally measured variation of the Bragg peak of carbon-ion beams by insertion of HDPE, PMMA, and POM, which were compared with analytical model calculations. Results: The theoretical calculation resulted in slightly reduced multiple scattering and severely increased nuclear interactions for HDPE, compared to water and the other plastics. The increase in attenuation of carbon ions for 20-cm range shift was experimentally measured to be 8.9% for HDPE, 2.5% for PMMA, and 0.0% for POM while PET was theoretically estimated to be in between PMMA and POM. The agreement between the measurements and the calculations was about 1% or better. Conclusions: For carbon-ion beams, POM was dosimetrically indistinguishable from water and the best of the plastics examined in this study. The poorest was HDPE, which would reduce the Bragg peak by 0.45% per cm range shift, although with marginal superiority for reduced multiple scattering. Between the two clear plastics, PET would be superior to PMMA in dosimetric water equivalence.

  3. Evaluation of a liquid ionization chamber for relative dosimetry in small and large fields of radiotherapy photon beams

    International Nuclear Information System (INIS)

    Benítez, E.M.; Casado, F.J.; García-Pareja, S.; Martín-Viera, J.A.; Moreno, C.; Parra, V.

    2013-01-01

    Commissioning and quality assurance of radiotherapy linear accelerators require measurement of the absorbed dose to water, and a wide range of detectors are available for absolute and relative dosimetry in megavoltage beams. In this paper, the PTW microLion isooctane-filled ionization chamber has been tested to perform relative measurements in a 6 MV photon beam from a linear accelerator. Output factors, percent depth dose and dose profiles have been obtained for small and large fields. These quantities have been compared with those from usual detectors in the routine practice. In order to carry out a more realistic comparison, an uncertainty analysis has been developed, taking type A and B uncertainties into account. The results present microLion as a good option when high spatial resolution is needed, thanks to its reduced sensitive volume. The liquid filling also provides a high signal compared to other detectors, like that based on air filling. Furthermore, the relative response of microLion when field size is varied suggests that this detector has energy dependence, since it is appreciated an over-response for small fields and an under-response for the large ones. This effect is more obvious for field sizes wider than 20 × 20 cm 2 , where the differences in percent depth dose at great depths exceed the uncertainties estimated in this study. - Highlights: • When high spatial resolution is required the results confirm the suitability of the liquid chamber. • Some energy dependence of the liquid detector can be appreciated in OFs and PDDs for small and large fields. • For field sizes >20 × 20 cm 2 , the differences in PDDs at great depths exceed the uncertainties estimated. • Some drawbacks should be considered: the time to reach stability, the high voltage supply required and the acquiring cost

  4. Radiotherapy

    International Nuclear Information System (INIS)

    Prosnitz, L.R.; Kapp, D.S.; Weissberg, J.B.

    1983-01-01

    This review highlights developments over the past decade in radiotherapy and attempts to summarize the state of the art in the management of the major diseases in which radiotherapy has a meaningful role. The equipment, radiobiology of radiotherapy and carcinoma of the lung, breast and intestines are highlighted

  5. Dosimetry for small size beams such as IMRT and stereotactic radiotherapy, is the concept of the dose at a point still relevant? proposal for a new methodology

    International Nuclear Information System (INIS)

    Ostrowsky, A.; Bordy, J.M.; Daures, J.; De Carlan, L.; Delaunay, F.

    2010-01-01

    Solving the problem of traceability of the absorbed dose to the tumour for the radiation fields of small and very small dimensions, like those used for new treatment modality usually results in the use of dosemeters of much smaller size than those of the beam. For the realisation of the reference in primary standards laboratories, the absence of technology likely to produce absolute small-size dosemeters leaves no possibility for the direct measurement of the absorbed dose at a point and implies the use of passive or active small-size transfer dosemeters. This report intends to introduce a new kind of dose quantity for radiotherapy similar do the Dose Area Product concept used in radiology. Such a new concept has to be propagated through the metrology chain, including the TPS, to the calculation of the absorbed dose to the tumour. (authors)

  6. Dosimetry for synchrotron stereotactic radiotherapy: from a macroscopic approach to microscopic energy deposits consideration

    International Nuclear Information System (INIS)

    Edouard, M.

    2010-01-01

    Numerous therapeutic strategies are currently being evaluated to find a curative treatment for high grade glioma. Among them, radiation therapy is partially effective but limited by the insufficient differential effect that can be reached between the dose delivered to the tumor compared to the one received by the healthy tissues. Synchrotron stereotactic radiotherapy aims at increasing this differential effect with a localized dose boost obtained by low energy x-rays stereotactic irradiations (≤ 100 keV) in presence of heavy elements restricted to the target area. This PhD work takes place in the general context of the future clinical trials foreseen at the European Synchrotron Radiation Facility. The first objective was to optimize the dose delivery to the target, at a macroscopic scale. We have demonstrated in particular that an even number of weighted beams was required to homogenize the tumor dose distribution. Microdosimetry studies were then performed to evaluate the dose delivered at the cellular level, taking into account the fine high-Z element distribution. These theoretical results have been compared to in vitro studies. Cell survival studies were performed using either a 3D glioma model (spheroids) or cells irradiated in suspension in an iodinated medium. (author) [fr

  7. Individual dosimetry in a radiotherapy department - evaluation between 1997 and 2004

    International Nuclear Information System (INIS)

    Macedo, S.C.; Jorge, L.; Alves, J.

    2005-01-01

    Full text: The occupational exposure is the exposure of workers due to their work. With the individual monitorization of the external radiation it is possible to get an approximated value of the effective dose and of the equivalent dose to the skin. The effective doses evaluation allows us to verify if these values are bellow the threshold established by law (a Portuguese law from 1990 established levels under 50 mSv/year for professionals and another law from 1997 established levels under 0,4 mSv/week, which is equivalent to 20 mSv/year, also for professionals). Methods and materials: we analyzed the values of the TLD dosimeters used by the workers during their professional activity between 1997 and 2004, in a Radiotherapy Department. Results: we separed the workers by professional groups and analyzed the equivalent dose in depth achieved (mSv/year). The workers were separed by physicians, medical physicists, technicians, nurses, helpers and secretaries. Conclusions: from the analysis of the results it is possible to demonstrate that the equivalent dose in depth achieved by the workers are under the threshold established and that we work under good conditions of radiation protection. (author)

  8. Lung dosimetry in a linac-MRI radiotherapy unit with a longitudinal magnetic field.

    Science.gov (United States)

    Kirkby, C; Murray, B; Rathee, S; Fallone, B G

    2010-09-01

    There is interest in developing linac-MR systems for MRI-guided radiation therapy. To date, the designs for such linac-MR devices have been restricted to a transverse geometry where the static magnetic field is oriented perpendicular to the direction of the incident photon beam. This work extends possibilities in this field by proposing and examining by Monte Carlo simulations, a probable longitudinal configuration where the magnetic field is oriented in the same direction as the photon beam. The EGSnrc Monte Carlo (MC) radiation transport codes with algorithms implemented to account for the magnetic field deflection of charged particles were used to compare dose distributions for linac-MR systems in transverse and longitudinal geometries. Specifically, the responses to a 6 MV pencil photon beam incident on water and lung slabs were investigated for 1.5 and 3.0 T magnetic fields. Further a five field lung plan was simulated in the longitudinal and transverse geometries across a range of magnetic field strengths from 0.2 through 3.0 T. In a longitudinal geometry, the magnetic field is shown to restrict the radial spread of secondary electrons to a small degree in water, but significantly in low density tissues such as lung in contrast to the lateral shift in dose distribution seen in the transverse geometry. These effects extend to the patient case, where the longitudinal configuration demonstrated dose distributions more tightly confined to the primary photon fields, which increased dose to the planning target volume (PTV), bettered dose homogeneity within a heterogeneous (in density) PTV, and reduced the tissue interface effects associated with the transverse geometry. Dosimetry issues observed in a transverse linac-MR geometry such as changes to the depth dose distribution and tissue interface effects were significantly reduced or eliminated in a longitudinal geometry on a representative lung plan. Further, an increase in dose to the PTV, resulting from the

  9. The use of a silicon strip detector dose magnifying glass in stereotactic radiotherapy QA and dosimetry

    International Nuclear Information System (INIS)

    Wong, J. H. D.; Knittel, T.; Downes, S.; Carolan, M.; Lerch, M. L. F.; Petasecca, M.; Perevertaylo, V. L.; Metcalfe, P.; Jackson, M.; Rosenfeld, A. B.

    2011-01-01

    Purpose: Stereotactic radiosurgery/therapy (SRS/SRT) is the use of radiation ablation in place of conventional surgical excision to remove or create fibrous tissue in small target volumes. The target of the SRT/SRS treatment is often located in close proximity to critical organs, hence the requirement of high geometric precision including a tight margin on the planning target volume and a sharp dose fall off. One of the major problems with quality assurance (QA) of SRT/SRS is the availability of suitable detectors with the required spatial resolution. The authors present a novel detector that they refer to as the dose magnifying glass (DMG), which has a high spatial resolution (0.2 mm) and is capable of meeting the stringent requirements of QA and dosimetry in SRS/SRT therapy. Methods: The DMG is an array of 128 phosphor implanted n + strips on a p-type Si wafer. The sensitive area defined by a single n + strip is 20x2000 μm 2 . The Si wafer is 375 μm thick. It is mounted on a 0.12 mm thick Kapton substrate. The authors studied the dose per pulse (dpp) and angular response of the detector in a custom-made SRS phantom. The DMG was used to determine the centers of rotation and positioning errors for the linear accelerator's gantry, couch, and collimator rotations. They also used the DMG to measure the profiles and the total scatter factor (S cp ) of the SRS cones. Comparisons were made with the EBT2 film and standard S cp values. The DMG was also used for dosimetric verification of a typical SRS treatment with various noncoplanar fields and arc treatments when applied to the phantom. Results: The dose per pulse dependency of the DMG was found to be cp agrees very well with the standard data with an average difference of 1.2±1.1%. Comparison of the relative intensity profiles of the DMG and EBT2 measurements for a simulated SRS treatment shows a maximum difference of 2.5%. Conclusions: The DMG was investigated for dose per pulse and angular dependency. Its

  10. Effect of Gold Nanoparticles on Prostate Dose Distribution under Ir-192 Internal and 18 MV External Radiotherapy Procedures Using Gel Dosimetry and Monte Carlo Method

    Directory of Open Access Journals (Sweden)

    Khosravi H.

    2015-03-01

    Full Text Available Background: Gel polymers are considered as new dosimeters for determining radiotherapy dose distribution in three dimensions. Objective: The ability of a new formulation of MAGIC-f polymer gel was assessed by experimental measurement and Monte Carlo (MC method for studying the effect of gold nanoparticles (GNPs in prostate dose distributions under the internal Ir-192 and external 18MV radiotherapy practices. Method: A Plexiglas phantom was made representing human pelvis. The GNP shaving 15 nm in diameter and 0.1 mM concentration were synthesized using chemical reduction method. Then, a new formulation of MAGIC-f gel was synthesized. The fabricated gel was poured in the tubes located at the prostate (with and without the GNPs and bladder locations of the phantom. The phantom was irradiated to an Ir-192 source and 18 MV beam of a Varian linac separately based on common radiotherapy procedures used for prostate cancer. After 24 hours, the irradiated gels were read using a Siemens 1.5 Tesla MRI scanner. The absolute doses at the reference points and isodose curves resulted from the experimental measurement of the gels and MC simulations following the internal and external radiotherapy practices were compared. Results: The mean absorbed doses measured with the gel in the presence of the GNPs in prostate were 15% and 8 % higher than the corresponding values without the GNPs under the internal and external radiation therapies, respectively. MC simulations also indicated a dose increase of 14 % and 7 % due to presence of the GNPs, for the same experimental internal and external radiotherapy practices, respectively. Conclusion: There was a good agreement between the dose enhancement factors (DEFs estimated with MC simulations and experiment gel measurements due to the GNPs. The results indicated that the polymer gel dosimetry method as developed and used in this study, can be recommended as a reliable method for investigating the DEF of GNPs in internal

  11. A multi-centre dosimetry audit on advanced radiotherapy in lung as part of the Isotoxic IMRT study

    Directory of Open Access Journals (Sweden)

    Yat Tsang

    2017-10-01

    Conclusion: This multi-centre dosimetry audit of complex IMRT/VMAT delivery provides confidence in the accuracy of modern planning and delivery systems in inhomogeneous tissues. The findings from this study can be used as a reference for future dosimetry audits.

  12. Radiotherapy

    Directory of Open Access Journals (Sweden)

    Rema Jyothirmayi

    1999-01-01

    Full Text Available Purpose. Conservative treatment in the form of limited surgery and post-operative radiotherapy is controversial in hand and foot sarcomas, both due to poor radiation tolerance of the palm and sole, and due to technical difficulties in achieving adequate margins.This paper describes the local control and survival of 41 patients with soft tissue sarcoma of the hand or foot treated with conservative surgery and radiotherapy. The acute and late toxicity of megavoltage radiotherapy to the hand and foot are described. The technical issues and details of treatment delivery are discussed. The factors influencing local control after radiotherapy are analysed.

  13. Standardized quality audit procedures for on-site dosimetry visits to radiotherapy hospitals. Report of the IAEA consultants' meeting, IAEA, Vienna, 27 September - 1 October 1999; revised in 2001

    International Nuclear Information System (INIS)

    Izewska, Joanna; Dutreix, A.; Followill, D.S.; Nisbet, A.; Novotny, J.; Sipila, P.; Dam, J. van

    2002-01-01

    Since 1969 the International Atomic Energy Agency (IAEA), together with the World Health Organization (WHO), has performed postal TLD audits to verify the calibration of radiotherapy beams in developing countries. The IAEA over the past 30 years, has verified the calibration of more than 3500 clinical photon beams at approximately 1000 radiotherapy hospitals. Detailed follow-up procedures have been implemented since 1996. When the TLD result of a participating institution falls outside the acceptance limits of ±5%, the institution is initially informed that there is a discrepancy and requested to try to identify the reasons why it occurred. The institution is not informed of the actual magnitude of the discrepancy (blind conditions) but is offered a second TLD audit. If the deviation cannot be resolved by the local radiotherapy institution or the national SSDL, then an on-site visit is suggested which, if accepted, is made by an IAEA expert in clinical dosimetry. The on-site visit includes a review of the dosimetry data and techniques, corrective measurements and ad-hoc training. The reasons for the discrepancy are then traced, explained, corrected and reported. Until the discrepancies are resolved and changes have been implemented by hospitals to ensure that the discrepancies do not reoccur, the safe and effective delivery of radiation doses to patients is questionable. This document provides a standardised set of procedures for resolving discrepancies during onsite visits to radiotherapy hospitals by the IAEA experts. The table below summarises the acceptance criteria to be used by the IAEA experts for dosimetry and mechanical parameters of the hospital treatment units. If some of the parameters are outside the acceptance criterion, it will not be possible for an institution to assure the adequate quality of the dosimetry practices in radiotherapy. The criteria are based on analyses of clinical data and the measurement uncertainties for various dosimetry and

  14. Radiotherapy

    International Nuclear Information System (INIS)

    Zedgenidze, G.A.; Kulikov, V.A.; Mardynskij, Yu.S.

    1984-01-01

    The technique for roentgenotopometric and medicamentous preparation of patients for radiotherapy has been reported in detail. The features of planning and performing of remote, intracavitary and combined therapy in urinary bladder cancer are considered. The more effective methods of radiotherapy have been proposed taking into account own experience as well as literature data. The comparative evaluation of treatment results and prognosis are given. Radiation pathomorphism of tumors and tissues of urinary bladder is considered in detail. The problems of diagnosis, prophylaxis and treatment of complications following radiodiagnosis and radiotherapy in patients with urinary bladder cancer are illustrated widely

  15. Woven TPS - A New Approach to TPS Design and Manufacturing

    Science.gov (United States)

    Feldman, Jay; Stackpoole, Mairead; Venkatapathy, Ethiraj

    2012-01-01

    NASA's Office of the Chief Technologist (OCT) Game Changing Division recently funded an effort to advance a Woven TPS (WTPS) concept. WTPS is a new approach to producing TPS materials that uses precisely engineered 3D weaving techniques to customize material characteristics needed to meet specific missions requirements for protecting space vehicles from the intense heating generated during atmospheric entry. Using WTPS, sustainable, scalable, mission-optimized TPS solutions can be achieved with relatively low life cycle costs compared with the high costs and long development schedules currently associated with material development and certification. WTPS leverages the mature state-of-the-art weaving technology that has evolved from the textile industry to design TPS materials with tailorable performance by varying material composition and properties via the controlled placement of fibers within a woven structure. The resulting material can be designed to perform optimally for a wide range of entry conditions encompassing NASAs current and future mission needs. WTPS enables these optimized TPS designs to be translated precisely into mission-specific, manufactured materials that can substantially increase the efficiency, utility, and robustness of heat shield materials compared to the current state-of-the-art material options. By delivering improved heat shield performance and affordability, this technology will impact all future exploration missions, from the robotic in-situ science missions to Mars, Venus and Saturn to the next generation of human missions. WTPS can change the way NASA develops, certifies, and integrates TPS into mission life cycles - instead of being a mission constraint, TPS will become a mission enabler. It is anticipated that WTPS will have direct impact on SMD, HEOMD and OCT and will be of interest for DoD and COTS applications. This presentation will overview the WTPS concept and present some results from initial testing completed.

  16. Thermoluminescence in medical dosimetry

    International Nuclear Information System (INIS)

    Rivera, T.

    2011-10-01

    The dosimetry by thermoluminescence (Tl) is applied in the entire world for the dosimetry of ionizing radiations specially to personal and medical dosimetry. This dosimetry method has been very interesting for measures in vivo because the Tl dosimeters have the advantage of being very sensitive in a very small volume and they are also equivalent to tissue and they do not need additional accessories (for example, cable, electrometer, etc.) The main characteristics of the diverse Tl materials to be used in the radiation measures and practical applications are: the Tl curve, the share homogeneity, the signal stability after the irradiation, precision and exactitude, the response in function with the dose and the energy influence. In this work a brief summary of the advances of the radiations dosimetry is presented by means of the thermally stimulated luminescence and its application to the dosimetry in radiotherapy. (Author)

  17. Radiotherapy: dosimetry planning

    International Nuclear Information System (INIS)

    Apzan, A.; Roziev, A.; Mileshin, O.; Klyopov, A.; Shishkanov, N.; Matusevich, E.

    2000-01-01

    The results of treatment of 142 case histories of 125 patients who had been treated with radioactive iodine at the Medical Radiological Research Center of Russian Academy of Medical Sciences from 1983 to 1999 are given in the presentation. Among the patients, 35 cases of diffuse toxic goiter with signs of thyrotoxicosis of a mild degree, 25 cases of diffuse toxic goiter with severe thyrotoxicosis, 6 cases of differentiated thyroid cancer with metastases to lymph nodes of the neck, 30 cases of thyroid cancer with metastases to lymph nodes of the neck and lung and 1 case of thyroid cancer with metastases to bones were diagnosed. Curves for accumulation and elimination of the radioiodine from the thyroid were built up for every patient. The curves show the true speed of accumulation of the iodine in the thyroid tissue and its elimination from the thyroid gland or its remnants, as well as from the whole body. (authors)

  18. Intensity-modulated radiotherapy or volumetric-modulated arc therapy in patients with head and neck cancer: Focus on salivary glands dosimetry.

    Science.gov (United States)

    Vallard, Alexis; Guy, Jean-Baptiste; Mengue Ndong, Sylvie; Vial, Nicolas; Rivoirard, Romain; Auberdiac, Pierre; Méry, Benoîte; Langrand-Escure, Julien; Espenel, Sophie; Moncharmont, Coralie; Ben Mrad, Majed; Diao, Peng; Goyet, Dominique; Magné, Nicolas

    2016-07-01

    Despite radiotherapy (RT) technical improvements, high salivary dysfunction rates are still reported in patients with head and neck squamous cell carcinoma (HNSCC). The purpose of the present study was to report salivary glands dosimetry with volumetric-modulated arc therapy (VMAT) and intensity-modulated RT (IMRT). Dosimetry of consecutive patients receiving IMRT or VMAT for proven HNSCC between 2007 and 2013 were retrospectively reviewed. Data of 609 patients were studied. Mean dose, mean maximum dose, and mean percentage of salivary gland volume receiving at least 26 Gy (V26) of the contralateral parotid were 24.50 Gy (range, 0-70.4 Gy), 39.08 Gy (range, 0.38-76.45 Gy), and 40.92% (range, 0% to 100%), respectively. Mean and maximum dose on contralateral submandibular gland were 48.18 Gy (range, 0.19-70.73 Gy), and 61.25 Gy (range, 0-75.8 Gy), respectively. Target volume coverage still has to be prioritized over organs at risk (OAR) sparing with new RT techniques. Submandibular glands are not sufficiently taken into account in guidelines. © 2016 Wiley Periodicals, Inc. Head Neck 38: 1028-1034, 2016. © 2016 Wiley Periodicals, Inc.

  19. A fast dual wavelength laser beam fluid-less optical CT scanner for radiotherapy 3D gel dosimetry I: design and development

    Science.gov (United States)

    Ramm, Daniel

    2018-02-01

    Three dimensional dosimetry by optical CT readout of radiosensitive gels or solids has previously been indicated as a solution for measurement of radiotherapy 3D dose distributions. The clinical uptake of these dosimetry methods has been limited, partly due to impracticalities of the optical readout such as the expertise and labour required for refractive index fluid matching. In this work a fast laser beam optical CT scanner is described, featuring fluid-less and dual wavelength operation. A second laser with a different wavelength is used to provide an alternative reference scan to the commonly used pre-irradiation scan. Transmission data for both wavelengths is effectively acquired simultaneously, giving a single scan process. Together with the elimination of refractive index fluid matching issues, scanning practicality is substantially improved. Image quality and quantitative accuracy were assessed for both dual and single wavelength methods. The dual wavelength scan technique gave improvements in uniformity of reconstructed optical attenuation coefficients in the sample 3D volume. This was due to a reduction of artefacts caused by scan to scan changes. Optical attenuation measurement accuracy was similar for both dual and single wavelength modes of operation. These results established the basis for further work on dosimetric performance.

  20. Monte Carlo dosimetry in simple geometries with interfaces: applications in radiotherapy; Dosimetria Monte Carlo en geometrias simples con interfases: aplicaciones en radioterapia

    Energy Technology Data Exchange (ETDEWEB)

    Rojas C, E.L

    2004-07-01

    In the last decade, dosimetry has evolved in an accelerated way due in part, to the development of new techniques and advances in instruments manufactured for several applications in Medical Physics. In order to improve achievements gotten with the use of radiation sources for therapeutic use, a guessed right dosimetry must be done and clinical data must be explained with the aid of investigation and supported with scientific bases. In this context, Monte Carlo (MC) method used to simulate radiation transport in materials, contribute with extensive knowledge and extremely useful information to that objective. MC dosimetry has some advantages over experimental and analytical dosimetry but it also has limitations. Maybe the most important is the computer time required to reach to an acceptable uncertainty level in a complex problem. Though this restrictive factor, a right application of MC simulation of radiation transport is a useful, reliable and versatile instrument for dosimetric calculations. From our point of view, the problem of heterogeneities in the sources or in the treatment targets in radiotherapy is of great importance, and this is the principal question to study aboard in this work. We use the MC simulation code Penelope to calculate some dosimetric quantities.The cases we study involve dosimetric aspects of different geometric distributions of radionuclides where interfaces are evident and must be taken into account. This work is divided in five chapters. In the first chapter we give a succinctly description of MC codes for simulation of the transport of particles in a medium and we describe the code Penelope. In chapter two, we study spherical distributions of radionuclides and the effect that interfaces in the target have in the dose received by the tumor. Specifically we study the application of radiocolloids with {sup 186} Re and {sup 32} P to treat homogeneous and nonhomogeneous cystic craniopharyngioma. Chapter three is dedicated to study plane

  1. Radiotherapy

    International Nuclear Information System (INIS)

    Pistenma, D.A.

    1980-01-01

    The need for radiotherapy research is exemplified by the 100,000 cancer patients who will fail treatment locally and/or regionally annually for the next several years but who would benefit from better local treatment modalities. Theoretically, all of the areas of investigation discussed in this projection paper have the potential to significantly improve local-regional treatment of cancer by radiotherapy alone or in combination with other modalities. In many of the areas of investigation discussed in this paper encouraging results have been obtained in cellular and animal tumor studies and in limited studies in humans as well. In the not too distant future the number of patients who would benefit from better local control may increase by tens of thousands if developments in chemotherapy and/or immunotherapy provide a means to eradicate disseminated microscopic foci of cancer. Thus the efforts to improve local-regional control take on even greater significance

  2. 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.)

  3. Ablative Ceramic Foam Based TPS, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — A novel composite material ablative TPS for planetary vehicles that can survive a dual heating exposure is proposed. NextGen's TPS concept is a bi-layer functional...

  4. Consistency in reference radiotherapy dosimetry: resolution of an apparent conundrum when 60Co is the reference quality for charged-particle and photon beams

    International Nuclear Information System (INIS)

    Andreo, Pedro; Wulff, Jörg; Burns, David T; Palmans, Hugo

    2013-01-01

    Substantial changes in ion chamber perturbation correction factors in 60 Co γ-rays, suggested by recent Monte Carlo (MC) calculations, would cause a decrease of about 1.5% in the reference dosimetry of all types of charged particles (electrons, protons and heavier ions) based on calculated k Q values. It has gone largely unnoticed that the ratio of calibration coefficients N D,w,Co60 and N K,air,Co60 yields an experimental value of F ch,Co60 = (s w-air  p ch ) Co60 through N D,air,Co60 . Coefficients provided by the IAEA and traceable to the BIPM for 91 NE-2571 chambers result in an average F ch,Co60 which is compared with published (and new) MC simulations and with the value in IAEA TRS-398. It is shown that TRS-398 agrees within 0.12% with the experimental F ch,Co60 . The 1.5% difference resulting from MC calculations (1.1% for the new simulations) cannot be justified using current fundamental data and BIPM standards if consistency in the entire dosimetry chain is sought. For photons, MC k Q factors are compared with TRS-398. Using the same uncertainty for W air , the two sets of data overlap considerably. Experimental k Q values from standards laboratories lie between the two sets of calculated values, showing no preference for one set over the other. Observed chamber-to-chamber differences, that include the effect of waterproof sleeves (also seen for 60 Co), justify the recommendation in TRS-398 for k Q values specifically measured for the user chamber. Current developments on I-values for the stopping powers of water and graphite are presented. A weighted average I water = 78 ± 2 eV is obtained from published experimental and DRF-based values; this would decrease s w-air for all types of radiotherapy beams between 0.3% and 0.6%, and would consequently decrease the MC derived F ch,Co60 . The implications of a recent proposal for I graphite = 81 eV are analysed, resulting in a potential decrease of 0.7% in N K,air,Co60 which would raise the

  5. Evaluation of superficial dosimetry between treatment planning system and measurement for several breast cancer treatment techniques

    Energy Technology Data Exchange (ETDEWEB)

    Akino, Yuichi; Das, Indra J.; Bartlett, Gregory K.; Zhang Hualin; Thompson, Elizabeth; Zook, Jennifer E. [Department of Radiation Oncology, Indiana University School of Medicine, Indianapolis, Indiana 46202 (United States) and Department of Radiation Oncology, Osaka University Graduate School of Medicine, Suita, Osaka 565-0871 (Japan); Department of Radiation Oncology, Indiana University School of Medicine, Indianapolis, Indiana 46202 (United States)

    2013-01-15

    Purpose: Dosimetric accuracy in radiation treatment of breast cancer is critical for the evaluation of cosmetic outcomes and survival. It is often considered that treatment planning systems (TPS) may not be able to provide accurate dosimetry in the buildup region. This was investigated in various treatment techniques such as tangential wedges, field-in-field (FF), electronic compensator (eComp), and intensity-modulated radiotherapy (IMRT). Methods: Under Institutional Review Board (IRB) exemption, radiotherapy treatment plans of 111 cases were retrospectively analyzed. The distance between skin surface and 95% isodose line was measured. For measurements, Gafchromic EBT2 films were used on a humanoid unsliced phantom. Multiple layers of variable thickness of superflab bolus were placed on the breast phantom and CT scanned for planning. Treatment plans were generated using four techniques with two different grid sizes (1 Multiplication-Sign 1 and 2.5 Multiplication-Sign 2.5 mm{sup 2}) to provide optimum dose distribution. Films were placed at different depths and exposed with the selected techniques. A calibration curve for dose versus pixel values was also generated on the same day as the phantom measurement was conducted. The DICOM RT image, dose, and plan data were imported to the in-house software. On axial plane of CT slices, curves were drawn at the position where EBT2 films were placed, and the dose profiles on the lines were acquired. The calculated and measured dose profiles were separated by check points which were marked on the films before irradiation. The segments of calculated profiles were stretched to match their resolutions to that of film dosimetry. Results: On review of treatment plans, the distance between skin and 95% prescribed dose was up to 8 mm for plans of 27 patients. The film measurement revealed that the medial region of phantom surface received a mere 45%-50% of prescribed dose. For wedges, FF, and eComp techniques, region around the

  6. Effect of different breathing patterns in the same patient on stereotactic ablative body radiotherapy dosimetry for primary renal cell carcinoma: A case study

    International Nuclear Information System (INIS)

    Pham, Daniel; Kron, Tomas; Foroudi, Farshad; Siva, Shankar

    2013-01-01

    Stereotactic ablative body radiotherapy (SABR) for primary renal cell carcinoma (RCC) targets requires motion management strategies to verify dose delivery. This case study highlights the effect of a change in patient breathing amplitude on the dosimetry to organs at risk and target structures. A 73-year-old male patient was planned for receiving 26 Gy of radiation in 1 fraction of SABR for a left primary RCC. The patient was simulated with four-dimensional computed tomography (4DCT) and the tumor internal target volume (ITV) was delineated using the 4DCT maximum intensity projection. However, the initially planned treatment was abandoned at the radiation oncologist's discretion after pretreatment cone-beam CT (CBCT) motion verification identified a greater than 50% reduction in superior to inferior diaphragm motion as compared with the planning 4DCT. This patient was resimulated with respiratory coaching instructions. To assess the effect of the change in breathing on the dosimetry to the target, each plan was recalculated on the data set representing the change in breathing condition. A change from smaller to larger breathing showed a 46% loss in planning target volume (PTV) coverage, whereas a change from larger breathing to smaller breathing resulted in an 8% decrease in PTV coverage. ITV coverage was similarly reduced by 8% in both scenarios. This case study highlights the importance of tools to verify breathing motion prior to treatment delivery. 4D image guided radiation therapy verification strategies should focus on not only verifying ITV margin coverage but also the effect on the surrounding organs at risk

  7. Commissioning of radiotherapy treatment planning systems: Testing for typical external beam treatment techniques. Report of the Coordinated Research Project (CRP) on Development of Procedures for Quality Assurance of Dosimetry Calculations in Radiotherapy

    International Nuclear Information System (INIS)

    2008-01-01

    Quality Assurance (QA) in the radiation therapy treatment planning process is essential to ensure accurate dose delivery to the patient and to minimize the possibility of accidental exposure. Computerized radiotherapy treatment planning systems (RTPSs) are now widely available in both industrialised and developing countries so, it is of special importance to support hospitals in the IAEA Member States in developing procedures for acceptance testing, commissioning and ongoing QA of their RTPSs. Responding to these needs, a group of experts developed a comprehensive report, the IAEA Technical Reports Series No 430 'Commissioning and quality assurance of computerized planning systems for radiation treatment of cancer', that provides the general framework and describes a large number of tests and procedures to be considered by the RTPS users. To provide practical guidance for implementation of IAEA Technical Reports Series No. 430 in radiotherapy hospitals and particularly in those with limited resources, a coordinated research project (CRP E2.40.13) 'Development of procedures for dosimetry calculation in radiotherapy' was established. The main goal of the project was to create a set of practical acceptance and commissioning tests for dosimetry calculations in radiotherapy, defined in a dedicated protocol. Two specific guidance publications that were developed in the framework of the Coordinated Research Project E2.40.13 are based on guidelines described in the IAEA Technical Report Series No. 430 and provide a step-by-step description for users at hospitals or cancer centres how to implement acceptance and commissioning procedures for their RTPSs. The first publication, 'Specification and acceptance testing of radiotherapy treatment planning systems' IAEA-TECDOC-1540 uses the International Electrotechnical Commission (IEC) standard IEC 62083 as its basis and addresses the procedures for specification and acceptance testing of RTPSs to be used by both manufacturers and

  8. Verification of the Accuracy of the Delivered Dose in Pelvic and Breast Cancer Radiotherapy by in-vivo Semi-Conductor Dosimetry

    Directory of Open Access Journals (Sweden)

    Hamidreza Shabani

    2009-12-01

    Full Text Available Introduction: Delivering maximum dose to tumor and minimum dose to normal tissues is the most important goal in radiotherapy. According to ICRU, the maximum acceptable uncertainty in the delivered dose compared to the prescribed dose should be lower than 5%, and this is because of the relationship between absorbed dose, tumor control and normal tissue damage. Absorbed dose accuracy is investigated by an in vivo dosimetry method. In this paper, we compared absorbed dose in the tumors of the breast and pelvic region against the calculated dose. The amount of deviations and the factors that cause this deviation in dose delivery to patients and some methods for decreasing them were evaluated. Materials and methods: The entrance and exit doses of 36 pelvic-region cancer patients and 38 breast cancer patients who were treated by cobalt-60 teletherapy were measured using p-type diodes. It should be noted that the transmission method was used to assess the dose at isocenter. Two ionization chambers (0.6 cc and 0.3 cc were used for calibration and determination of the correction coefficients in water and slab phantoms. Deviations between calculated and measured doses of entrance, exit and midline points were calculated and the results were shown using histograms. Results: The average and standard deviation for entrance, exit and midline points for pelvis cancer were assessed to be about 0.10%, -1.86% and -1.35% for mean deviation and 5.03%, 7.32% and 5.86% for standard deviation, respectively. The corresponding data for breast cancer were 0.78%, 5.29% and 3.59% for mean deviation and 5.97%, 10.23% and 9.86%, respectively. There was no significant difference between the calculated and measured doses (p > 0.1, except exit dose in breast cancer (p < 0.05. The temperature and angle of incidence correction factors were neglected due to their less than 1% deviations. Discussion and Conclusions: Some error sources are patient setup error, patient motion and

  9. Combined Yttrium-90 microsphere selective internal radiation therapy and external beam radiotherapy in patients with hepatocellular carcinoma: From clinical aspects to dosimetry.

    Directory of Open Access Journals (Sweden)

    Ti-Hao Wang

    Full Text Available Selective internal radiation therapy (SIRT is an effective treatment strategy for unresectable hepatocellular carcinoma (HCC patients. However, the prognoses of patients with portal vein thrombosis, extra-hepatic metastases, or residual tumors remain poor when treated with SIRT alone. In these patients, sequential external beam radiotherapy (EBRT may offer a chance of salvage. Here, we reported the clinical outcomes and the detailed dosimetry analysis of 22 patients treated with combination therapy.Between October 2011 and May 2015, 22 consecutive patients who underwent EBRT after yttrium-90 (90Y SIRT were included in this study. The post-SIRT 90Y bremsstrahlung SPECT/CT of each patient was transferred to dose distribution by adopting the local deposition hypothesis. The patient-specific 3-dimensional biological effective dose distribution of combined SIRT and EBRT was generated. The overall survival and safety were evaluated. The relationship between dosimetric parameters and liver toxicity was analyzed.The mean administered activity of SIRT was 1.50 GBq (range: 0.5-2.8. The mean prescribed dose of EBRT was 42.3 Gy (range: 15-63 in 14 fractions (range: 5-15 and was targeted to the residual liver tumor in 12 patients (55%, portal vein thrombosis in 11 patients (50%, and perihilar lymphadenopathies in 4 patients (18%. The overall 1-, 2-, and 3-year survival rates were 59.8%, 47.9%, and 47.9%, respectively. Overall, 8 patients (36% developed > grade 2 liver toxicities, and the Child-Pugh score prior to EBRT strongly affected the toxicity risk. A dosimetry analysis restricted to 18 Child-Pugh A/B patients showed that the V100 (The fraction of normal liver exposed to more than 100 Gy to V140 significance differed between patients who did or did not experience hepatotoxicity. The V110 was the strongest predictor of hepatotoxicity (18.6±11.6% vs 29.5±5.8%; P = 0.030.Combined therapy is feasible and safe if patients are carefully selected

  10. Combined Yttrium-90 microsphere selective internal radiation therapy and external beam radiotherapy in patients with hepatocellular carcinoma: From clinical aspects to dosimetry.

    Science.gov (United States)

    Wang, Ti-Hao; Huang, Pin-I; Hu, Yu-Wen; Lin, Ko-Han; Liu, Ching-Sheng; Lin, Yi-Yang; Liu, Chien-An; Tseng, Hsiou-Shan; Liu, Yu-Ming; Lee, Rheun-Chuan

    2018-01-01

    Selective internal radiation therapy (SIRT) is an effective treatment strategy for unresectable hepatocellular carcinoma (HCC) patients. However, the prognoses of patients with portal vein thrombosis, extra-hepatic metastases, or residual tumors remain poor when treated with SIRT alone. In these patients, sequential external beam radiotherapy (EBRT) may offer a chance of salvage. Here, we reported the clinical outcomes and the detailed dosimetry analysis of 22 patients treated with combination therapy. Between October 2011 and May 2015, 22 consecutive patients who underwent EBRT after yttrium-90 (90Y) SIRT were included in this study. The post-SIRT 90Y bremsstrahlung SPECT/CT of each patient was transferred to dose distribution by adopting the local deposition hypothesis. The patient-specific 3-dimensional biological effective dose distribution of combined SIRT and EBRT was generated. The overall survival and safety were evaluated. The relationship between dosimetric parameters and liver toxicity was analyzed. The mean administered activity of SIRT was 1.50 GBq (range: 0.5-2.8). The mean prescribed dose of EBRT was 42.3 Gy (range: 15-63) in 14 fractions (range: 5-15) and was targeted to the residual liver tumor in 12 patients (55%), portal vein thrombosis in 11 patients (50%), and perihilar lymphadenopathies in 4 patients (18%). The overall 1-, 2-, and 3-year survival rates were 59.8%, 47.9%, and 47.9%, respectively. Overall, 8 patients (36%) developed > grade 2 liver toxicities, and the Child-Pugh score prior to EBRT strongly affected the toxicity risk. A dosimetry analysis restricted to 18 Child-Pugh A/B patients showed that the V100 (The fraction of normal liver exposed to more than 100 Gy) to V140 significance differed between patients who did or did not experience hepatotoxicity. The V110 was the strongest predictor of hepatotoxicity (18.6±11.6% vs 29.5±5.8%; P = 0.030). Combined therapy is feasible and safe if patients are carefully selected. Specifically

  11. SU-F-T-566: Absolute Film Dosimetry for Stereotactic Radiosurgery and Stereotactic Body Radiotherapy Quality Assurance Using Gafchromic EBT3 Films

    Energy Technology Data Exchange (ETDEWEB)

    Wen, N; Lu, S; Qin, Y; Huang, Y; Zhao, B; Liu, C; Chetty, I [Henry Ford Health System, Detroit, MI (United States)

    2016-06-15

    Purpose: To evaluate the dosimetric uncertainty associated with Gafchromic (EBT3) films and establish an absolute dosimetry protocol for Stereotactic Radiosurgery (SRS) and Stereotactic Body Radiotherapy (SBRT). Methods: EBT3 films were irradiated at each of seven different dose levels between 1 and 15 Gy with open fields, and standard deviations of dose maps were calculated at each color channel for evaluation. A scanner non-uniform response correction map was built by registering and comparing film doses to the reference diode array-based dose map delivered with the same doses. To determine the temporal dependence of EBT3 films, the average correction factors of different dose levels as a function of time were evaluated up to four days after irradiation. An integrated film dosimetry protocol was developed for dose calibration, calibration curve fitting, dose mapping, and profile/gamma analysis. Patient specific quality assurance (PSQA) was performed for 93 SRS/SBRT treatment plans. Results: The scanner response varied within 1% for the field sizes less than 5 × 5 cm{sup 2}, and up to 5% for the field sizes of 10 × 10 cm{sup 2}. The scanner correction method was able to remove visually evident, irregular detector responses found for larger field sizes. The dose response of the film changed rapidly (∼10%) in the first two hours and plateaued afterwards, ∼3% change between 2 and 24 hours. The mean uncertainties (mean of the standard deviations) were <0.5% over the dose range 1∼15Gy for all color channels for the OD response curves. The percentage of points passing the 3%/1mm gamma criteria based on absolute dose analysis, averaged over all tests, was 95.0 ± 4.2. Conclusion: We have developed an absolute film dose dosimetry protocol using EBT3 films. The overall uncertainty has been established to be approximately 1% for SRS and SBRT PSQA. The work was supported by a Research Scholar Grant, RSG-15-137-01-CCE from the American Cancer Society.

  12. 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)

  13. In-vivo dosimetry in radiotherapy: a comparison of the response of semiconductor and thermoluminescence (TLD700) dosemeters

    Energy Technology Data Exchange (ETDEWEB)

    Vynckier, S. [Universite Catholique de Louvain, Brussels (Belgium). Cliniques Universitaires St. Luc; Greffe, J.L.; Loncol, T.; Vanneste, F.; Octave-Prignot, M.; Denis, J.M.; De Patoul, N.

    1995-12-01

    Semiconductor dosemeters and thermoluminescence dosemeters were calibrated in view of in-vivo dosimetry. Their response in a 8 MV photon beam and the respective correction factors for the treatment conditions were systematically studied. A total of 249 entrance and exit measurements with this dual detector combination were performed, mainly for treatments of the head and neck region. The resulting entrance and exit doses were compared with the expected doses at these positions, calculated on basis of the treatment and patient parameters. The results at the entrance showed a value of 1.010 (2.8% for the ratio of the measured to the calculated dose by diodes, 1.013) 4.9% for the ratio of the measured to the calculated dose by TLD and 1.003 (3.6% for the ratio of the measured dose by TLD to diodes. With respect the exit dose, the results were 0.998) 4.9%, 1.016 (7.7% and 1.019) 7.0% respectively after correction for the heterogeneity`s. Although the standard deviation for the TLD dosemeters is systematically larger than the standard deviation for the diodes, it is concluded that both dosemeters will yield similar results for-in-vivo dosimetry, if utilized under the same conditions.

  14. Radiotherapy

    International Nuclear Information System (INIS)

    Hubert, D.

    2009-01-01

    Context: the descendants of persons treated for a childhood cancer could have an increased risk of genetic disease because of mutagenic anti cancerous treatments received by their parents. 3963 survivors of cancer in childhood ( born between 12950 and 1984) have been identified from the Danish register of cancer, constituting the 'survivors' cohort. 5657 of their brothers and sisters constituting the 'siblings' cohort have been identified from the Danish central register of the population. All of the live-born children born from these two cohorts have been identified from this register, allowing to include 1715 descendants from the 'survivors' cohort and 6009 descendants from the 'siblings' cohort. The congenital malformations have been found out from the national hospital register. The irradiation doses to the gonads and uterus have been defined by using the usual radiotherapy protocols. Conclusion: This study shows that the anti cancerous treatments for children do not seem increase the risk of congenital malformations in their progeny. (N.C.)

  15. Dosimetry of pion beams

    International Nuclear Information System (INIS)

    Dicello, J.F.

    1975-01-01

    Negative pion beams are probably the most esoteric and most complicated type of radiation which has been suggested for use in clinical radiotherapy. Because of the limited availability of pion beams in the past, even to nuclear physicists, there exist relatively fewer basic data for this modality. Pion dosimetry is discussed

  16. aSi-EPID transit signal calibration for dynamic beams: a needful step for the IMRT in vivo dosimetry.

    Science.gov (United States)

    Greco, Francesca; Piermattei, Angelo; Azario, Luigi; Placidi, Lorenzo; Cilla, Savino; Caivano, Rocchina; Fusco, Vincenzo; Fidanzio, Andrea

    2013-10-01

    This work reports a method based on correlation functions to convert EPID transit signals into in vivo dose values at the isocenter point, D iso, of dynamic IMRT beams supplied by Varian linac. Dose reconstruction for intensity-modulated beams required significant corrections of EPID response, due to the X-ray component transmitted through multileaf collimator. The algorithm was formulated using a set of simulated IMRT beams. The beams were parameterized by means of a fluence inhomogeneity index, FI, introduced to describe the degree of beam modulation with respect to open beams. This way, all dosimetric parameters involved in D iso reconstruction algorithm, such as the correlation functions, the correction factor for EPID to phantom distance and the modulated tissue maximum ratios, were determined as a function of the FI index. Clinical IMRT beams were used to irradiate a homogeneous phantom, and for each beam, the agreement between the reconstructed dose, D iso, and the dose computed by TPS, D iso,TPS, was well within 5 %. Moreover, the average ratios, R, between the D iso, and D iso,TPS, resulted equal to 1.002 ± 0.030. Thirty-five IMRT fields of 5 different patients undergoing radiotherapy for head-neck tumors were tested and the results were displayed on a computer screen after 2 min from the end of the treatment. However, 350 in vivo tests supplied an average ratio R equal to 1.004 ± 0.040. The in vivo dosimetry procedure here presented is among the objectives of a National Project financially supported by the Istituto Nazionale di Fisica Nucleare for the development of in vivo dosimetry procedures (Piermattei et al. in Nucl Instrum Methods Phys Res B 274:42-50, 2012) connected to the Record-Verify system of the radiotherapy center.

  17. Dosimetry of small circular beams of high energy photons for stereotactic radiosurgery and radiotherapy: the use of small ionization chambers

    International Nuclear Information System (INIS)

    Mazal, A.; Gaboriauid, G.; Zefkili, S.; Rosenwald, J.C.; Boutaudon, S.; Pontvert, D.

    1999-01-01

    The irradiation of small targets in the brain in a singe fraction (radiosurgery) or with a fractionated approach (stereotactic radiosurgery) with small beams of photons requires specific conditions to measure and to model the dosimetric data needed for treatment planning. In this work we present the method and materials adopted in our institution since 1988 to perform the dosimetry of high energy (6-23) circular photon beams with diameters ranging from 10 to 40 mm at the isocenter of linear accelerators, and its evolution as new dosimetric material became commercially available. in circular ionization chambers of small dimensions. We want to answer the following questions: Which are the minimal basic data needed to model small circular beams of high energy photons? Can we extrapolate or convert data from conventional data of larger beams? Which are the detectors well adapted for these kind of measurements and for which range of beam sizes?

  18. [{sup 131}I]-TYR3-octreotide: clinical dosimetry and use for internal radiotherapy of metastatic paraganglioma and carcinoid tumors

    Energy Technology Data Exchange (ETDEWEB)

    Baulieu, Jean-Louis E-mail: baulieu@med.univ-tours; Resche, Isabelle; Bardies, Manuel; Chauvet, Alain Faivre; Lecloirec, Joseph; Malhaire, Jean-Pierre; Thomas, Eric; Faurous, Patrick; Sassolas, Genevieve; Pourcelot, Leandre; Chatal, Jean-Francois; Guilloteau, Denis; Besnard, Jean-Claude

    2000-11-01

    Dosimetry and therapeutic application of [{sup 131}I]-Tyr3-octreotide were evaluated in three patients with metastatic paraganglioma and carcinoid tumor. The in vitro stability of [{sup 131}I]-Tyr3-octreotide was verified. Tumor uptake and residence time were between 0.02 and 0.1% and 0.5 to 9.8 h, respectively. The calculated tumor radiation doses were between 0.105 and 0.696 mGy{center_dot}MBq{sup -1}. No intolerance or adverse effects were observed after the therapeutic doses (3.3-6.6 GBq). A partial tumor response was obtained in one patient and no response occurred in two patients.

  19. 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)

  20. SU-E-T-483: In Vivo Dosimetry of Conventional and Rotational Intensity Modulated Radiotherapy Using Integral Quality Monitor (IQM)

    Energy Technology Data Exchange (ETDEWEB)

    Lin, L; Qian, J; Gonzales, R; Keck, J; Armour, E; Wong, J [Johns Hopkins University, Baltimore, MD (United States)

    2015-06-15

    Purpose: To investigate the accuracy, sensitivity and constancy of integral quality monitor (IQM), a new system for in vivo dosimetry of conventional intensity modulated radiation therapy (IMRT) or rotational volumetric modulated arc therapy (VMAT) Methods: A beta-version IQM system was commissioned on an Elekta Infinity LINAC equipped with 160-MLCs Agility head. The stationary and rotational dosimetric constancy of IQM was evaluated, using five-field IMRT and single-or double-arc VMAT plans for prostate and head-and-neck (H&N) patients. The plans were delivered three times over three days to assess the constancy of IQM response. Picket fence (PF) fields were used to evaluate the sensitivity of detecting MLC leaf errors. A single leaf offset was intentionally introduced during delivery of various PF fields with segment apertures of 3×1, 5×1, 10×1, and 24×1cm2. Both 2mm and 5mm decrease in the field width were used. Results: Repeated IQM measurements of prostate and H&N IMRT deliveries showed 0.4 and 0.5% average standard deviation (SD) for segment-by-segment comparison and 0.1 and 0.2% for cumulative comparison. The corresponding SDs for VMAT deliveries were 6.5, 9.4% and 0.7, 1.3%, respectively. Statistical analysis indicates that the dosimetric differences detected by IQM were significant (p < 0.05) in all PF test deliveries. The largest average IQM signal response of a 2 mm leaf error was found to be 2.1% and 5.1% by a 5mm leaf error for 3×1 cm2 field size. The same error in 24×1 cm2 generates a 0.7% and 1.4% difference in the signal. Conclusion: IQM provides an effective means for real-time dosimetric verification of IMRT/ VMAT treatment delivery. For VMAT delivery, the cumulative dosimetry of IQM needs to be used in clinical practice.

  1. Tissue interfaces dosimetry in small field radiotherapy with alanine/EPR mini dosimeters and Monte Carlo-Penelope simulation

    Energy Technology Data Exchange (ETDEWEB)

    Vega R, J. L.; Nicolucci, P.; Baffa, O. [Universidade de Sao Paulo, FFCLRP, Departamento de Fisica, Av. Bandeirantes 3900, Bairro Monte Alegre, 14040-901 Ribeirao Preto, Sao Paulo (Brazil); Chen, F. [Universidade Federale do ABC, CCNH, Rua Santa Adelia 166, Bangu, 09210-170 Santo Andre, Sao Paulo (Brazil); Apaza V, D. G., E-mail: josevegaramirez@yahoo.es [Universidad Nacional de San Agustin de Arequipa, Departamento de Fisica, Arequipa (Peru)

    2014-08-15

    The dosimetry system based on alanine mini dosimeters plus K-Band EPR spectrometer was tested in the tissue-interface dosimetry through the percentage depth-dose (Pdd) determination for 3 x 3 cm{sup 2} and 1 x 1 cm{sup 2} radiation fields sizes. The alanine mini dosimeters were produced by mechanical pressure from a mixture of 95% L-alanine and 5% polyvinyl alcohol (Pva) acting as binder. Nominal dimensions of these mini dosimeters were 1 mm diameter and 3 mm length as well as 3 - 4 mg mass. The EPR spectra of the mini dosimeters were registered using a K-Band (24 GHz) EPR spectrometer. The mini dosimeters were placed in a nonhomogeneous phantom and irradiated with 20 Gy in a 6 MV PRIMUS Siemens linear accelerator, with a source-to-surface distance of 100 cm using the small fields previously mentioned. The cylindrical non-homogeneous phantom was comprised of several disk-shaped plates of different materials in the sequence acrylic-bone cork-bone-acrylic, with dimensions 15 cm diameter and 1 cm thick. The plates were placed in descending order, starting from top with four acrylic plates followed by two bone plates plus eight cork plates plus two bone plates and finally, four acrylic plates (4-2-8-2-4). Pdd curves from the treatment planning system and from Monte Carlo simulation with Penelope code were determined. Mini dosimeters Pdd results show good agreement with Penelope, better than 95% for the cork homogeneous region and 97.7% in the bone heterogeneous region. In the first interface region, between acrylic and bone, it can see a dose increment of 0.6% for mini dosimeters compared to Penelope. At the second interface, between bone and cork, there is 9.1% of dose increment for mini dosimeter relative to Penelope. For the third (cork-bone) and fourth (bone-acrylic) interfaces, the dose increment for mini dosimeters compared to Penelope was 4.1% both. (Author)

  2. Prone versus supine positioning for whole and partial-breast radiotherapy: A comparison of non-target tissue dosimetry

    International Nuclear Information System (INIS)

    Kirby, Anna M.; Evans, Philip M.; Donovan, Ellen M.; Convery, Helen M.; Haviland, Joanna S.; Yarnold, John R.

    2010-01-01

    Purpose: To compare non-target tissue (including left-anterior-descending coronary-artery (LAD)) dosimetry of prone versus supine whole (WBI) and partial-breast irradiation (PBI). Methods and materials: Sixty-five post-lumpectomy breast cancer patients underwent CT-imaging supine and prone. On each dataset, the whole-breast clinical-target-volume (WB-CTV), partial-breast CTV (tumour-bed + 15 mm), ipsilateral-lung and chest-wall were outlined. Heart and LAD were outlined in left-sided cases (n = 30). Tangential-field WBI and PBI plans were generated for each position. Mean LAD, heart, and ipsilateral-lung doses (x mean ), maximum LAD (LAD max ) doses, and the volume of chest-wall receiving 50 Gy (V 50Gy ) were compared. Results: Two-hundred and sixty plans were generated. Prone positioning reduced heart and LAD doses in 19/30 WBI cases (median reduction in LAD mean = 6.2 Gy) and 7/30 PBI cases (median reduction in LAD max = 29.3 Gy) (no difference in 4/30 cases). However, prone positioning increased cardiac doses in 8/30 WBI (median increase in LAD mean = 9.5 Gy) and 19/30 PBI cases (median increase in LAD max = 22.9 Gy) (no difference in 3/30 cases). WB-CTV > 1000cm 3 was associated with improved cardiac dosimetry in the prone position for WBI (p = 0.04) and PBI (p = 0.04). Prone positioning reduced ipsilateral-lung mean in 65/65 WBI and 61/65 PBI cases, and chest-wall V 50Gy in all WBI cases. PBI reduced normal-tissue doses compared to WBI in all cases, regardless of the treatment position. Conclusions: In the context of tangential-field WBI and PBI, prone positioning is likely to benefit left-breast-affected women of larger breast volume, but to be detrimental in left-breast-affected women of smaller breast volume. Right-breast-affected women are likely to benefit from prone positioning regardless of breast volume.

  3. Commissioning of Portal Dosimetry and characterization of an EPID; Comissionamento de Portal Dosimetry e caracterizacao de EPID

    Energy Technology Data Exchange (ETDEWEB)

    Olbi, D.S.; Sales, C.P. [Universidade de Sao Paulo (USP), SP (Brazil). Faculdade de Medicina; Nakandakari, M.V.N., E-mail: diego.olbi@hc.fm.usp.br [Instituto do Cancer do Estado de Sao Paulo, SP (Brazil). Servico de Radioterapia

    2016-07-01

    The development of technologies compensator blocks, MLC, high dose rate accelerators, treatment planning systems, among others, permitted that new treatment techniques in radiotherapy were created. Such techniques have the capacity to modulate radiation beam fluency (IMRT, VMAT), or to deliver high doses in few fractions or unique fractions (SRS). Following the same tendency, quality control of planning became more complex. It is necessary to evaluate the fluency delivered by the accelerator. Its levels of does and its spatial distribution should co-occur with the fluency calculated by TPS. Acquisition of new detector devices in quality control of treatments is fundamental to apply techniques. Portal Vision is a device EPID has the capacity to operate either in image mode or dosimetry mode, with the allowance of Portal Dosimetry. To evaluated planning in IMRT, the device is irradiated using planning e, therefore, the fluency measured is compared with calculated fluency, through gamma analysis. The aim of this work was to perform tests of commissioning of this device. (author)

  4. Calculation of uncertainties in the protocol of dosimetry for Co 60 beams in Radiotherapy; Calculo de incertidumbres en el protocolo de dosimetria para haces de Co 60 en Radioterapia

    Energy Technology Data Exchange (ETDEWEB)

    Velazquez M, S.; Carrera M, F.; Sanchez S, J. [Hospital Juan Ramon Jimenez, Ronda Norte s/n 21005 Huelva (Spain)

    1998-12-31

    The objective in this work is to show how the uncertainty is possible to know in the determination of the absorbed dose in Co 60 photon beams and to establish in a rational form, tolerance levels for this. It is took as base the spanish protocol of dosimetry in Radiotherapy. We have been centered in a Co 60 beam. We utilized the statistical theory of little samples. We allowed to suggest a new approach about the treatment of the tolerance levels and the uncertainty of the measurement. After two years of experience in the practical hospitable application we have gotten to put around 1 % uncertainty in the absolute dosimetry of the Co 60 beam. The presented protocol allows to execute the accuracy requirements in the determination of absorbed doses. (Author)

  5. Dosimetric verification of radiotherapy treatment planning systems in Serbia: national audit.

    Science.gov (United States)

    Rutonjski, Laza; Petrović, Borislava; Baucal, Milutin; Teodorović, Milan; Cudić, Ozren; Gershkevitsh, Eduard; Izewska, Joanna

    2012-09-12

    Independent external audits play an important role in quality assurance programme in radiation oncology. The audit supported by the IAEA in Serbia was designed to review the whole chain of activities in 3D conformal radiotherapy (3D-CRT) workflow, from patient data acquisition to treatment planning and dose delivery. The audit was based on the IAEA recommendations and focused on dosimetry part of the treatment planning and delivery processes. The audit was conducted in three radiotherapy departments of Serbia. An anthropomorphic phantom was scanned with a computed tomography unit (CT) and treatment plans for eight different test cases involving various beam configurations suggested by the IAEA were prepared on local treatment planning systems (TPSs). The phantom was irradiated following the treatment plans for these test cases and doses in specific points were measured with an ionization chamber. The differences between the measured and calculated doses were reported. The measurements were conducted for different photon beam energies and TPS calculation algorithms. The deviation between the measured and calculated values for all test cases made with advanced algorithms were within the agreement criteria, while the larger deviations were observed for simpler algorithms. The number of measurements with results outside the agreement criteria increased with the increase of the beam energy and decreased with TPS calculation algorithm sophistication. Also, a few errors in the basic dosimetry data in TPS were detected and corrected. The audit helped the users to better understand the operational features and limitations of their TPSs and resulted in increased confidence in dose calculation accuracy using TPSs. The audit results indicated the shortcomings of simpler algorithms for the test cases performed and, therefore the transition to more advanced algorithms is highly desirable.

  6. Dosimetric verification of radiotherapy treatment planning systems in Serbia: national audit

    Directory of Open Access Journals (Sweden)

    Rutonjski Laza

    2012-09-01

    Full Text Available Abstract Background Independent external audits play an important role in quality assurance programme in radiation oncology. The audit supported by the IAEA in Serbia was designed to review the whole chain of activities in 3D conformal radiotherapy (3D-CRT workflow, from patient data acquisition to treatment planning and dose delivery. The audit was based on the IAEA recommendations and focused on dosimetry part of the treatment planning and delivery processes. Methods The audit was conducted in three radiotherapy departments of Serbia. An anthropomorphic phantom was scanned with a computed tomography unit (CT and treatment plans for eight different test cases involving various beam configurations suggested by the IAEA were prepared on local treatment planning systems (TPSs. The phantom was irradiated following the treatment plans for these test cases and doses in specific points were measured with an ionization chamber. The differences between the measured and calculated doses were reported. Results The measurements were conducted for different photon beam energies and TPS calculation algorithms. The deviation between the measured and calculated values for all test cases made with advanced algorithms were within the agreement criteria, while the larger deviations were observed for simpler algorithms. The number of measurements with results outside the agreement criteria increased with the increase of the beam energy and decreased with TPS calculation algorithm sophistication. Also, a few errors in the basic dosimetry data in TPS were detected and corrected. Conclusions The audit helped the users to better understand the operational features and limitations of their TPSs and resulted in increased confidence in dose calculation accuracy using TPSs. The audit results indicated the shortcomings of simpler algorithms for the test cases performed and, therefore the transition to more advanced algorithms is highly desirable.

  7. Thermal Protection System Materials (TPSM): Conformal Ablative TPS (CA-TPS) Project

    Data.gov (United States)

    National Aeronautics and Space Administration — CA-TPS is leveraging earlier investments made by ARMD’s Hypersonic and HEOMD’s ETDD program that matured the concept from TRL 1 to 2.CA-TPS starts with...

  8. A systematic review of the precision and accuracy of dose measurements in photon radiotherapy using polymer and Fricke MRI gel dosimetry

    International Nuclear Information System (INIS)

    MacDougall, N.D.; Pitchford, W.G.; Smith, M.A.

    2002-01-01

    The purpose of this work is to undertake a critical appraisal of the evidence in the published literature concerning the basic parameters of accuracy and precision associated with the use of Fricke and polymer gels (in conjunction with MR imaging) as radiation dosimeters in photon radiotherapy, condensing and analysing the body of published information (to the end of April 2002). A systematic review was undertaken addressing specific issues of precision and accuracy asking defined questions of the published literature. Accuracy and precision in relation to gel dosimetry were defined. Information was obtained from published, peer-reviewed journals. A defined search strategy utilizing MeSH headings and keywords, with extensive use of cross-referencing, identified 115 references dealing with gel dosimetry. Exclusion criteria were used to select only data from publications which would give unequivocal evidence. For accuracy, results had to be compared with an ionization chamber as gold standard and all gel samples had to be manufactured in the same batch. For precision, in addition to gels being from the same batch, samples must all have been irradiated at the same time and scanned simultaneously (or within a short time frame). Many results were found demonstrating 'dose mapping' examples using gels. However, there were very few publications containing firm evidence of precision and accuracy. There was no evidence which fulfilled our criteria about accuracy or precision using Fricke gels. For polymer gels only one paper was found for accuracy (4% (Low et al 1999 Med. Phys. 26 1542-51)) and precision (1.7% (Baldock et al 1998 Phys. Med. Biol. 43 695-702)); however, both were carried out at only one dose level. If the exclusion criteria were relaxed to include accuracy results comparing gel to a non gold standard dosimeter (e.g. TLD), results give a median accuracy of 10% (range 8-23.5%) for polymer gel (Cosgrove et al 2000 Phys. Med. Biol. 45 1195-210, De Deene et al

  9. Evaluation and optimization of the new EBT2 radiochromic film dosimetry system for patient dose verification in radiotherapy

    Energy Technology Data Exchange (ETDEWEB)

    Richley, L; John, A C; Coomber, H; Fletcher, S, E-mail: lucy.richley@uhbristol.nhs.u [Bristol Haematology and Oncology Centre, Bristol, BS2 8ED (United Kingdom)

    2010-05-07

    A new radiochromic film, the yellow Gafchromic EBT2, has been marketed as a drop-in replacement for the discontinued blue EBT film. In order to verify the manufacturer's claims prior to clinical use, EBT2 was characterized in transmission, and the less commonly used, reflection modes with an Epson Expression 10000XL A3 flatbed scanner. The red channel was confirmed to provide the greatest sensitivity and was used for all measurements. The post-irradiation darkening of the film was investigated, and the relative response was found to be dose dependent with higher doses stabilizing earlier than lower doses. After 13 h all dose levels had stabilized to within 1% of their value at 24 h. Uniformity of irradiated EBT2 films was within 0.8% and 1.2% (2SD of signal), in reflection and transmission modes, respectively. The light scattering effect, arising from the structure and thickness of EBT2, was found to give rise to an apparent scanner non-uniformity of up to 5.5% in signal. In reflection mode, differences of up to 1.2% were found between the signal obtained from a small film fragment (5 x 5 cm{sup 2}) and the signal obtained from the same fragment bordered by extra film. Further work is needed to determine the origin of this effect, as there will be implications for reflection dosimetry of intensity modulated fields; reflection mode cannot yet be regarded as a viable alternative to transmission mode. Our results suggest that EBT2 film is a valid alternative, rather than a direct replacement for EBT film.

  10. Breast dosimetry in complementary radiotherapy with sodium pertechnetate-{sup 99m}-Tc (Na{sup 99m}TcO{sub 4}{sup -}) balloon at neoplasia

    Energy Technology Data Exchange (ETDEWEB)

    Lima, Carla Flavia de; Campos, Tarcisio P. R. de, E-mail: tprcampos@pq.cnpq.br, E-mail: carla.flavia@terra.com.br [Universidade Federal de Minas Gerais (UFMG), Belo Horizonte, BH (Brazil). Departamento de Engenharia Nuclear. Programa de Ciencias e Tecnicas Nucleares

    2013-07-01

    A dosimetric analyzes was performed at breast tissue in which a sodium pertechnetate-{sup 99m}Tc filled balloon was placed. An additional dose booster can be used as a complementary method to the surgical treatment in patients with breast cancer. The methodology involved the development of dosimetry in a physical phantom and a computational voxel model. Radiochromic films were calibrated providing dose versus optical density (OD) response from sample films taken at the surface of the balloon up to 10 cm far with the theoretical dose provided by MCNP modeling in water-equivalent model. A voxel model of the breast, developed at the SISCODES software, with an filled balloon inside was simulated at the MCNP code in order to generate the spatial dose distribution. Spatial dose distributions and the doses at surfaces of the breast, including those received in the chest wall, skin and lung were generated. The dosimetric results allow validating the dose in the tumor bed and adjacent health tissues. The simulations show that the application of sodium pertechnetate-{sup 99m}Tc implies high dose in the breast tissue adjacent to the tumor and preserves vital adjacent structures. As conclusion, the balloon presents itself as a viable option for the adjunctive treatment of breast cancer in patients who have appropriate indication. Irradiation with sodium pertechnetate-{sup 99m}Tc generates high doses in breast tissue and consequently in the tumor bed. Adjuvant radiation therapy in situ with sodium pertechnetate-{sup 99m}Tc balloon has low cost, availability and reduced time of treatment, decreasing the side effects of conventional radiotherapy. In progress, the dose versus OD mathematical representation will be used to identify absorbed doses at planar film placed at a breast phantom in order to generate maps of breast doses. (author)

  11. An in-vivo dosimetry procedure for Elekta step and shoot IMRT.

    Science.gov (United States)

    Cilla, S; Azario, L; Greco, F; Fidanzio, A; Porcelli, A; Grusio, M; Macchia, G; Morganti, A G; Meluccio, D; Piermattei, A

    2014-06-01

    The aim of this work was to extend an in-vivo dosimetry (IVD) method, previously developed by the authors for 3D-conformal radiotherapy, to step and shoot IMRT treatments for pelvic tumors delivered by Elekta linacs. The algorithm is based on correlation functions to convert EPID transit signals into in-vivo dose values at the isocenter point, Diso. The EPID images were obtained by the so-called "IMRT Dosimetric Weighting" mode as a superposition of many segment fields. This way each integral dosimetric image could be acquired in about 10 s after the end of beam delivery and could be processed while delivering the successive IMRT beams. A specific algorithm for Diso reconstruction especially featured for step and shoot IMRT was implemented using a fluence inhomogeneity index, FI, introduced to describe the degree of beam modulation with respect to open beams. A γ-analysis of 2D-EPID images obtained day to day, resulted rapid enough to verify the plan delivery reproducibility. Fifty clinical IMRT beams, planned for patients undergoing radiotherapy of pelvic tumors, were used to irradiate a homogeneous phantom. For each beam the agreement between the reconstructed dose, Diso, and the TPS computed dose, Diso,TPS, was well within 5%, while the mean ratio R = Diso/Diso,TPS resulted for 250 tests equal to 1.006 ± 0.036. The same beams were checked in vivo, i.e. during patient treatment delivery, obtaining 500 tests whose average R ratio resulted equal to 1.011 ± 0.042. The γ-analysis of the EPID images with 5% 3 mm criteria supplied 85% of the tests with pass rates γ(mean) ≤ 0.5 and P(γFisica Medica. Published by Elsevier Ltd. All rights reserved.

  12. Hippocampal Dosimetry Predicts Neurocognitive Function Impairment After Fractionated Stereotactic Radiotherapy for Benign or Low-Grade Adult Brain Tumors

    International Nuclear Information System (INIS)

    Gondi, Vinai; Hermann, Bruce P.; Mehta, Minesh P.; Tomé, Wolfgang A.

    2012-01-01

    Purpose: To prospectively evaluate the association between hippocampal dose and long-term neurocognitive function (NCF) impairment for benign or low-grade adult brain tumors treated with fractionated stereotactic radiotherapy (FSRT). Methods and Materials: Adult patients with benign or low-grade adult brain tumors were treated with FSRT per institutional practice. No attempt was made to spare the hippocampus. NCF testing was conducted at baseline and 18 months follow-up, on a prospective clinical trial. Regression-based standardized z scores were calculated by using similar healthy control individuals evaluated at the same test–retest interval. NCF impairment was defined as a z score ≤−1.5. After delineation of the bilateral hippocampi according to the Radiation Therapy Oncology Group contouring atlas, dose–volume histograms were generated for the left and right hippocampi and for the composite pair. Biologically equivalent doses in 2-Gy fractions (EQD 2 ) assuming an α/β ratio of 2 Gy were computed. Fisher’s exact test and binary logistic regression were used for univariate and multivariate analyses, respectively. Dose–response data were fit to a nonlinear model. Results: Of 29 patients enrolled in this trial, 18 completed both baseline and 18-month NCF testing. An EQD 2 to 40% of the bilateral hippocampi >7.3 Gy was associated with impairment in Wechsler Memory Scale-III Word List (WMS-WL) delayed recall (odds ratio [OR] 19.3; p = 0.043). The association between WMS-WL delayed recall and EQD 2 to 100% of the bilateral hippocampi >0.0 Gy trended to significance (OR 14.8; p = 0.068). Conclusion: EQD 2 to 40% of the bilateral hippocampi greater than 7.3 Gy is associated with long-term impairment in list-learning delayed recall after FSRT for benign or low-grade adult brain tumors. Given that modern intensity-modulated radiotherapy techniques can reduce the dose to the bilateral hippocampi below this dosimetric threshold, patients should be enrolled in

  13. Hippocampal Dosimetry Predicts Neurocognitive Function Impairment After Fractionated Stereotactic Radiotherapy for Benign or Low-Grade Adult Brain Tumors

    International Nuclear Information System (INIS)

    Gondi, Vinai; Hermann, Bruce P.; Mehta, Minesh P.; Tomé, Wolfgang A.

    2013-01-01

    Purpose: To prospectively evaluate the association between hippocampal dose and long-term neurocognitive function (NCF) impairment for benign or low-grade adult brain tumors treated with fractionated stereotactic radiotherapy (FSRT). Methods and Materials: Adult patients with benign or low-grade adult brain tumors were treated with FSRT per institutional practice. No attempt was made to spare the hippocampus. NCF testing was conducted at baseline and 18 months follow-up, on a prospective clinical trial. Regression-based standardized z scores were calculated by using similar healthy control individuals evaluated at the same test–retest interval. NCF impairment was defined as a z score ≤−1.5. After delineation of the bilateral hippocampi according to the Radiation Therapy Oncology Group contouring atlas, dose–volume histograms were generated for the left and right hippocampi and for the composite pair. Biologically equivalent doses in 2-Gy fractions (EQD 2 ) assuming an α/β ratio of 2 Gy were computed. Fisher’s exact test and binary logistic regression were used for univariate and multivariate analyses, respectively. Dose–response data were fit to a nonlinear model. Results: Of 29 patients enrolled in this trial, 18 completed both baseline and 18-month NCF testing. An EQD 2 to 40% of the bilateral hippocampi >7.3 Gy was associated with impairment in Wechsler Memory Scale-III Word List (WMS-WL) delayed recall (odds ratio [OR] 19.3; p = 0.043). The association between WMS-WL delayed recall and EQD 2 to 100% of the bilateral hippocampi >0.0 Gy trended to significance (OR 14.8; p = 0.068). Conclusion: EQD 2 to 40% of the bilateral hippocampi greater than 7.3 Gy is associated with long-term impairment in list-learning delayed recall after FSRT for benign or low-grade adult brain tumors. Given that modern intensity-modulated radiotherapy techniques can reduce the dose to the bilateral hippocampi below this dosimetric threshold, patients should be enrolled in

  14. Volumetric tumor burden and its effect on brachial plexus dosimetry in head and neck intensity-modulated radiotherapy

    Energy Technology Data Exchange (ETDEWEB)

    Romesser, Paul B.; Qureshi, Muhammad M.; Kovalchuk, Nataliya; Truong, Minh Tam, E-mail: mitruong@bu.edu

    2014-07-01

    To determine the effect of gross tumor volume of the primary (GTV-P) and nodal (GTV-N) disease on planned radiation dose to the brachial plexus (BP) in head and neck intensity-modulated radiotherapy (IMRT). Overall, 75 patients underwent definitive IMRT to a median total dose of 69.96 Gy in 33 fractions. The right BP and left BP were prospectively contoured as separate organs at risk. The GTV was related to BP dose using the unpaired t-test. Receiver operating characteristics curves were constructed to determine optimized volumetric thresholds of GTV-P and GTV-N corresponding to a maximum BP dose cutoff of > 66 Gy. Multivariate analyses were performed to account for factors associated with a higher maximal BP dose. A higher maximum BP dose (> 66 vs ≤ 66 Gy) correlated with a greater mean GTV-P (79.5 vs 30.8 cc; p = 0.001) and ipsilateral GTV-N (60.6 vs 19.8 cc; p = 0.014). When dichotomized by the optimized nodal volume, patients with an ipsilateral GTV-N ≥ 4.9 vs < 4.9 cc had a significant difference in maximum BP dose (64.2 vs 59.4 Gy; p = 0.001). Multivariate analysis confirmed that an ipsilateral GTV-N ≥ 4.9 cc was an independent predictor for the BP to receive a maximal dose of > 66 Gy when adjusted individually for BP volume, GTV-P, the use of a low anterior neck field technique, total planned radiation dose, and tumor category. Although both the primary and the nodal tumor volumes affected the BP maximal dose, the ipsilateral nodal tumor volume (GTV-N ≥ 4.9 cc) was an independent predictor for high maximal BP dose constraints in head and neck IMRT.

  15. Evaluation of the treatment planning system of three-dimensional conformal external radiotherapy in Hospital Mexico of San Jose, Costa Rica

    International Nuclear Information System (INIS)

    Venegas Rojas, Deybith

    2014-01-01

    An evaluation and analysis are realized of dosimetry of the treatment planning system (TPS) of three-dimensional conformal external radiotherapy in the Servicio de Radioterapia of the Hospital Mexico of Costa Rica. An evaluation procedure is proposed based on IAEA-TECDOC-1540 document, and may continue to be applied periodically in this or other radiotherapy services. Tests realized have checked the representation of distances and electronics densities transferred to the TPS, match with those of real objects. The 16 tests applied have represented situations of real treatments with different configurations and beam modifiers in the equipment used daily. The tests have measured the absorbed dose to water in different significant points at different depths, using photon beams of 6 MeV and 18 MeV. The physical parameters of the tests were simulated. The absorbed dose has been calculated at specified points. The XiO and Eclipse TPS have been used with the calculation algorithms: Superposition, Convolution and AAA. The results of the calculations are evaluated with statistical methods and comparing them with the measurements of absorbed dose. A generalized tendency has been detected toward negative relative errors, implying an underestimation of the dose by the TPS; due to a difference found in the accelerator output factor respect to its commissioning. The AAA algorithm has determined a better performance, although with greater difficulties of calculus in the region of build-up. Convolution and Superposition algorithms have had similar performances and both have presented problems in high depths and out of edges of the fields. The result of the dosimetric evaluation has been satisfactory in real conditions of equipment; but several particularities have been found that should be reviewed and adjusted. The precision of the TPS has been adequate in the majority of situations important for treatment planning. [author] [es

  16. Dosimetry for small size beams such as IMRT and stereotactic radiotherapy, is the concept of the dose at a point still relevant? proposal for a new methodology; Dosimetrie pour les faisceaux de petites dimensions pour la RCMI et la stereotaxie. Le concept de dose en un point est il adapte? proposition pour une nouvelle methodologie

    Energy Technology Data Exchange (ETDEWEB)

    Ostrowsky, A.; Bordy, J.M.; Daures, J.; De Carlan, L.; Delaunay, F.

    2010-07-01

    Solving the problem of traceability of the absorbed dose to the tumour for the radiation fields of small and very small dimensions, like those used for new treatment modality usually results in the use of dosemeters of much smaller size than those of the beam. For the realisation of the reference in primary standards laboratories, the absence of technology likely to produce absolute small-size dosemeters leaves no possibility for the direct measurement of the absorbed dose at a point and implies the use of passive or active small-size transfer dosemeters. This report intends to introduce a new kind of dose quantity for radiotherapy similar do the Dose Area Product concept used in radiology. Such a new concept has to be propagated through the metrology chain, including the TPS, to the calculation of the absorbed dose to the tumour. (authors)

  17. Assessment of leakage dose in vivo in patients undergoing radiotherapy for breast cancer

    Directory of Open Access Journals (Sweden)

    Peta Lonski

    2018-01-01

    Full Text Available Background and purpose: Accurate quantification of the relatively small radiation doses delivered to untargeted regions during breast irradiation in patients with breast cancer is of increasing clinical interest for the purpose of estimating long-term radiation-related risks. Out-of-field dose calculations from commercial planning systems however may be inaccurate which can impact estimates for long-term risks associated with treatment. This work compares calculated and measured dose out-of-field and explores the application of a correction for leakage radiation. Materials and methods: Dose calculations of a Boltzmann transport equation solver, pencil beam-type, and superposition-type algorithms from a commercial treatment planning system (TPS were compared with in vivo thermoluminescent dosimetry (TLD measurements conducted out-of-field on the contralateral chest at points corresponding to the thyroid, axilla and contralateral breast of eleven patients undergoing tangential beam radiotherapy for breast cancer. Results: Overall, the TPS was found to under-estimate doses at points distal to the radiation field edge with a modern linear Boltzmann transport equation solver providing the best estimates. Application of an additive correction for leakage (0.04% of central axis dose improved correlation between the measured and calculated doses at points greater than 15 cm from the field edge. Conclusions: Application of a correction for leakage doses within peripheral regions is feasible and could improve accuracy of TPS in estimating out-of-field doses in breast radiotherapy. Keywords: Breast radiotherapy, TLD, Leakage dose, Dose calculation algorithm

  18. Design and test of a scintillation dosimeter for dosimetry measurements of high energy radiotherapy beams; Conception et realisation d'un dosimetre a scintillation adapte a la dosimetrie de faisceaux de rayonnements ionisants en faisceaux de rayonnements ionisants en radiotherapie

    Energy Technology Data Exchange (ETDEWEB)

    Fontbonne, J.M

    2002-12-01

    This work describes the design and evaluation of the performances of a scintillation dosimeter developed for the dosimetry of radiation beams used in radiotherapy. The dosimeter consists in a small plastic scintillator producing light which is guided by means of a plastic optical fiber towards photodetectors. In addition to scintillation, high energy ionizing radiations produce Cerenkov light both in the scintillator and the optical fiber. Based on a wavelength analysis, we have developed a deconvolution technique to measure the scintillation light in the presence of Cerenkov light. We stress the advantages that are anticipated from plastic scintillator, in particular concerning tissue or water equivalence (mass stopping power, mass attenuation or mass energy absorption coefficients). We show that detectors based on this material have better characteristics than conventional dosimeters such as ionisation chambers or silicon detectors. The deconvolution technique is exposed, as well as the calibration procedure using an ionisation chamber. We have studied the uncertainty of our dosimeter. The electronics noise, the fiber transmission, the deconvolution technique and the calibration errors give an overall combined experimental uncertainty of about 0,5%. The absolute response of the dosimeter is studied by means of depth dose measurements. We show that absolute uncertainty with photons or electrons beams with energies ranging from 4 MeV to 25 MeV is less than {+-} 1 %. Last, at variance with other devices, our scintillation dosimeter does not need dose correction with depth. (author)

  19. Fiber optically coupled radioluminescence detectors: A short review of key strengths and weaknesses of BCF-60 and Al2O3:C scintillating-material based systems in radiotherapy dosimetry applications

    Science.gov (United States)

    Buranurak, S.; Andersen, C. E.

    2017-06-01

    Radiotherapy technologies have improved for several decades aiming to effectively destroy cancerous tissues without overdosing surrounding healthy tissues. In order to fulfil this requirement, accurate and precise dosimetry systems play an important role. Throughout the years, ionization chambers have been used as a standard detector for basic linear accelerator calibrations and reference dosimetry in hospitals. However, they are not ideal for all treatment modalities: and limitations and difficulties have been reported in case of (i) small treatment fields, (ii) strong magnetic field used in the new hybrid MRI LINAC/cobalt systems, and (iii) in vivo measurements due to safety-issues related to the high operating voltage. Fiber optically coupled luminescence detectors provide a promising supplement to ionization chambers by offering the capability of real-time in vivo dose monitoring with high time resolution. In particular, the all-optical nature of these detectors is an advantage for in vivo measurements due to the absence of high voltage supply or electrical wire that could cause harm to the patient or disturb the treatment. Basically, fiber-coupled luminescence detector systems function by radiation-induced generation of radioluminescence from a sub-mm size organic/inorganic phosphor. A thin optical fiber cable is used for guiding the radioluminescence to a photomultiplier tube or similar sensitive light detection systems. The measured light intensity is proportional to dose rate. Throughout the years, developments and research of the fiber detector systems have undergone in several groups worldwide. In this article, the in-house developed fiber detector systems based on two luminescence phosphors of (i) BCF-60 polystyrene-based organic plastic scintillator and (ii) carbon-doped aluminum oxide crystal (Al2O3:C) are reviewed with comparison to the same material-based systems reported in the literature. The potential use of these detectors for reference

  20. Evaluation of radiochromic films EBT3 for in-vivo dosimetry in radiotherapy treatments with photons; Evaluacion de peliculas radiocromicas EBT3 para dosimetria in vivo en tratamientos de radioterapia con fotones

    Energy Technology Data Exchange (ETDEWEB)

    Galvan de la C, O. O.; Rivera M, T. [IPN, Centro de Investigacion en Ciencia Aplicada y Tecnologia Avanzada, Av. Legaria No. 694, Col. Irrigacion, 11500 Mexico D. F. (Mexico); Garcia G, O. A.; Larraga G, J. M., E-mail: olinca@ciencias.unam.mx [Instituto Nacional de Neurologia y Neurocirugia, Laboratorio de Fisica Medica, Insurgentes Sur 3877, Col. La Fama, 14269 Mexico D. F. (Mexico)

    2015-10-15

    Full text: In-vivo dosimetry is a challenge in radiotherapy due to the measures are carried out in reference conditions outside; there is no balance of charged particle and beam consists of photons own and contamination electrons. Detectors that are useful for such measures should be sufficiently small and thin so they do not disturb the beam and do not alter the dose on target. In this paper the radiochromic films Gafchromic model EBT3 are evaluated as potential detectors for in-vivo dosimetry; measurements were carried out in solid water phantom on the surface, with films of dimensions 3 x 3 cm{sup 2}. Irradiations were performed with a linear accelerator Novalis of 6 MV. Comparison between dose values found with a diode type Sfd detector (IBA dosimetry, Germany) and a diamond detector CVD (PTW-Freiburg) for 2 different sized of field (5 x 5 cm{sup 2} and 10 x 10 cm{sup 2}) on the surface of a water phantom scanning was realized. The total spreading factor (Tsf) measured on surface was of 0.831 ± 4.6%; which is greater 12.9% than Tsf measured at a depth of maximum dose. This difference may be due to the contribution of scattered electrons to the beam exit. The measures must be corroborated with Monte Carlo simulations, which they will be validated on surface by the Abdel-Rahman [et al.] method; this mechanism will determine if the films are useful detectors for in-vivo dosimetry clinically. (Author)

  1. Radiation dosimetry

    CERN Document Server

    Hine, Gerald J; Hine, Gerald J

    1956-01-01

    Radiation Dosimetry focuses on the advancements, processes, technologies, techniques, and principles involved in radiation dosimetry, including counters and calibration and standardization techniques. The selection first offers information on radiation units and the theory of ionization dosimetry and interaction of radiation with matter. Topics include quantities derivable from roentgens, determination of dose in roentgens, ionization dosimetry of high-energy photons and corpuscular radiations, and heavy charged particles. The text then examines the biological and medical effects of radiation,

  2. EPR/alanine dosimetry for two therapeutic proton beams

    International Nuclear Information System (INIS)

    Marrale, Maurizio; Carlino, Antonio; Gallo, Salvatore; Longo, Anna; Panzeca, Salvatore; Bolsi, Alessandra; Hrbacek, Jan; Lomax, Tony

    2016-01-01

    In this work the analysis of the electron paramagnetic resonance (EPR) response of alanine pellets exposed to two different clinical proton beams employed for radiotherapy is performed. One beam is characterized by a passive delivery technique and is dedicated to the eyes treatment (OPTIS2 beam line). Alanine pellets were irradiated with a 70 MeV proton beam corresponding to 35 mm range in eye tissue. We investigated how collimators with different sizes and shape used to conform the dose to the planned target volume influence the delivered dose. For this purpose we performed measurements with varying the collimator size (Output Factor) and the results were compared with those obtained with other dosimetric techniques (such as Markus chamber and diode detector). This analysis showed that the dosimeter response is independent of collimator diameter if this is larger than or equal to 10 mm. The other beam is characterized by an active spot-scanning technique, the Gantry1 beam line (maximum energy 230 MeV), and is used to treat deep-seated tumors. The dose linearity of alanine response in the clinical dose range was tested and the alanine dose response at selected locations in depth was measured and compared with the TPS planned dose in a quasi-clinical scenario. The alanine response was found to be linear in the dose in the clinical explored range (from 10 to 70 Gy). Furthermore, a depth dose profile in a quasi-clinical scenario was measured and compared to the dose computed by the Treatment Planning System PSIPLAN. The comparison of calibrated proton alanine measurements and TPS dose shows a difference under 1% in the SOBP and a “quenching” effect up to 4% in the distal part of SOBP. The positive dosimetric characteristics of the alanine pellets confirm the feasibility to use these detectors for “in vivo” dosimetry in clinical proton beams.

  3. SU-G-TeP2-03: Comparison of Standard Dosimetry Protocol in Japan and AAPM TG-51 Addendum in Order to Establish Optimal Dosimetry for FFF Beam

    Energy Technology Data Exchange (ETDEWEB)

    Matsunaga, T; Adachi, Y [Department of Radiology, Seirei Hamamatsu General Hospital, Hamamatsu, Shizuoka (Japan); Hayashi, N [Graduate School of Health Sciences, Fujita Health University, Tayoake, Aichi (Japan); Nozue, M [Department of Radiation Oncology, Seirei Hamamtsu General Hospital, Hamamatsu, Shizuoka (Japan)

    2016-06-15

    Purpose: Japan Standard Dosimetry of Absorbed dose to water in external beam radiotherapy (JSDP12) is widely used to measure radiation dose in radiotherapy. However, JSDP12 does not take flattening-filter-free (FFF) beam into consideration. In addition, JSDP12 applied TPR20,10 for dose quality index for photon beam. The purpose of this study is to compare JSDP12 with AAPM TG-51 addendum in order to establish optimal dosimetry procedure for FFF beam. Method: We evaluated the ion-recombination factor (ks) and the correction factor of radial beam profile (Prp) in FFF beam dosimetry. The ks was introduced by 2 voltages method and verified by Jaffe’s plot. The Prp was given by both film measurement and calculation of treatment planning system, and compared them. Next, we compared the dose quality indexes (kQ) between TPR20,10 method and PDD(10)x method. Finally we considered optimal dosimetry protocol for FFF photon beam using JSDP12 with referring TG-51 addendum protocols. The FFF photon beams of 6 MV (6X-FFF) and 10 MV (10X-FFF) from TrueBeam were investigated in this study. Results: The ks for 6X-FFF and 10X-FFF beams were 1.005 and 1.010, respectively. The Prp of 0.6 cc ionization chamber for 6X-FFF and 10X-FFF beams (Film, TPS) were (1.004, 1.008) and (1.005, 1.008), respectively. The kQ for 6X-FFF and 10X-FFF beams (JSDP12, TG-51 addendum) were (0.9950, 0.9947) and (0.9851, 0.9845), respectively. The most effective factor for uncertainty in FFF photon beam measurement was Prp for JSDP12 formalism. Total dosimetric differences between JSDP12 and TG-51 addendum for 6X-FFF and 10X-FFF were -0.47% and -0.73%, respectively. Conclusion: The total dosimetric difference between JSDP12 and TG-51 addendum was within 1%. The introduction of kQ given by JSDP is feasible for FFF photon beam dosimetry. However, we think Prp should be considered for optimal dosimetry procedure even if JSDP12 is used for FFF photon beam dosimetry.

  4. SU-F-T-115: Uncertainty in the Esophagus Dose in Retrospective Epidemiological Study of Breast Cancer Radiotherapy Patients

    Energy Technology Data Exchange (ETDEWEB)

    Mosher, E; Kim, S; Lee, C [Division of Cancer Epidemiology and Genetics, National Cancer Institute, Rockville, MD (United States); Lee, C [Department of Radiation Oncology, University of Michigan, Ann Arbor, MI (United States); Pelletier, C; Jung, J [Department of Physics, East Carolina University Greenville, NC (United States); Jones, E [Radiology and Imaging Sciences Clinical Center, National Institutes of Health, Bethesda, MD (United States)

    2016-06-15

    Purpose: Epidemiological studies of second cancer risks in breast cancer radiotherapy patients often use generic patient anatomy to reconstruct normal tissue doses when CT images of patients are not available. To evaluate the uncertainty involved in the dosimetry approach, we evaluated the esophagus dose in five sample patients by simulating breast cancer treatments. Methods: We obtained the diagnostic CT images of five anonymized adult female patients in different Body Mass Index (BMI) categories (16– 36kg/m2) from National Institutes of Health Clinical Center. We contoured the esophagus on the CT images and imported them into a Treatment Planning System (TPS) to create treatment plans and calculate esophagus doses. Esophagus dose was calculated once again via experimentally-validated Monte Carlo (MC) transport code, XVMC under the same geometries. We compared the esophagus doses from TPS and the MC method. We also investigated the degree of variation in the esophagus dose across the five patients and also the relationship between the patient characteristics and the esophagus doses. Results: Eclipse TPS using Analytical Anisotropic Algorithm (AAA) significantly underestimates the esophagus dose in breast cancer radiotherapy compared to MC. In the worst case, the esophagus dose from AAA was only 40% of the MC dose. The Coefficient of Variation across the patients was 48%. We found that the maximum esophagus dose was up to 2.7 times greater than the minimum. We finally observed linear relationship (Dose = 0.0218 × BMI – 0.1, R2=0.54) between patient’s BMI and the esophagus doses. Conclusion: We quantified the degree of uncertainty in the esophagus dose in five sample breast radiotherapy patients. The results of the study underscore the importance of individualized dose reconstruction for the study cohort to avoid misclassification in the risk analysis of second cancer. We are currently extending the number of patients up to 30.

  5. 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

  6. Development of manual procedures for care of pregnant patients in radiotherapy service

    International Nuclear Information System (INIS)

    Scarabino, M.L.; Ruggeri, R.M.; Colombo, S.; Mairal, L.; Sardi, M.E.

    2013-01-01

    The work involves the creation of a manual of procedures for the care of pregnant patients in a radiotherapy center in which each instance of treatment is included, from the obstetrician-oncology comprehensive assessment during admission to establishing controls newborn and its subsequent development in multidisciplinary team. For the preparation of the manual had to design an anthropomorphic phantom that resembles a pregnant woman, which was used to carry out internal and external dosimetry. In turn imparted calculations fetal doses using TPS, imaging tests with MRI, avoiding the use of the tomograph and adapted to the resonator involved were carried immobilizer. All experiences and progress made during the treated cases are introduced in the procedures manual, making it a dynamic tool for continuous improvement for the institution

  7. Individual dosimetry of workers and patients: implementation and perspectives

    International Nuclear Information System (INIS)

    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.

    2008-01-01

    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.)

  8. Evaluation of six TPS algorithms in computing entrance and exit doses

    Science.gov (United States)

    Metwaly, Mohamed; Glegg, Martin; Baggarley, Shaun P.; Elliott, Alex

    2014-01-01

    Entrance and exit doses are commonly measured in in vivo dosimetry for comparison with expected values, usually generated by the treatment planning system (TPS), to verify accuracy of treatment delivery. This report aims to evaluate the accuracy of six TPS algorithms in computing entrance and exit doses for a 6 MV beam. The algorithms tested were: pencil beam convolution (Eclipse PBC), analytical anisotropic algorithm (Eclipse AAA), AcurosXB (Eclipse AXB), FFT convolution (XiO Convolution), multigrid superposition (XiO Superposition), and Monte Carlo photon (Monaco MC). Measurements with ionization chamber (IC) and diode detector in water phantoms were used as a reference. Comparisons were done in terms of central axis point dose, 1D relative profiles, and 2D absolute gamma analysis. Entrance doses computed by all TPS algorithms agreed to within 2% of the measured values. Exit doses computed by XiO Convolution, XiO Superposition, Eclipse AXB, and Monaco MC agreed with the IC measured doses to within 2%‐3%. Meanwhile, Eclipse PBC and Eclipse AAA computed exit doses were higher than the IC measured doses by up to 5.3% and 4.8%, respectively. Both algorithms assume that full backscatter exists even at the exit level, leading to an overestimation of exit doses. Despite good agreements at the central axis for Eclipse AXB and Monaco MC, 1D relative comparisons showed profiles mismatched at depths beyond 11.5 cm. Overall, the 2D absolute gamma (3%/3 mm) pass rates were better for Monaco MC, while Eclipse AXB failed mostly at the outer 20% of the field area. The findings of this study serve as a useful baseline for the implementation of entrance and exit in vivo dosimetry in clinical departments utilizing any of these six common TPS algorithms for reference comparison. PACS numbers: 87.55.‐x, 87.55.D‐, 87.55.N‐, 87.53.Bn PMID:24892349

  9. Software tool for portal dosimetry research.

    Science.gov (United States)

    Vial, P; Hunt, P; Greer, P B; Oliver, L; Baldock, C

    2008-09-01

    This paper describes a software tool developed for research into the use of an electronic portal imaging device (EPID) to verify dose for intensity modulated radiation therapy (IMRT) beams. A portal dose image prediction (PDIP) model that predicts the EPID response to IMRT beams has been implemented into a commercially available treatment planning system (TPS). The software tool described in this work was developed to modify the TPS PDIP model by incorporating correction factors into the predicted EPID image to account for the difference in EPID response to open beam radiation and multileaf collimator (MLC) transmitted radiation. The processes performed by the software tool include; i) read the MLC file and the PDIP from the TPS, ii) calculate the fraction of beam-on time that each point in the IMRT beam is shielded by MLC leaves, iii) interpolate correction factors from look-up tables, iv) create a corrected PDIP image from the product of the original PDIP and the correction factors and write the corrected image to file, v) display, analyse, and export various image datasets. The software tool was developed using the Microsoft Visual Studio.NET framework with the C# compiler. The operation of the software tool was validated. This software provided useful tools for EPID dosimetry research, and it is being utilised and further developed in ongoing EPID dosimetry and IMRT dosimetry projects.

  10. The dosimetric control in radiotherapy

    International Nuclear Information System (INIS)

    Veres, A.

    2009-01-01

    The author first presents the thermoluminescent dosimetry method developed by the Equal-Estro Laboratory to control radiotherapy systems, according to which dosimeters are mailed by the radiotherapy centres to the laboratory, and then analyzed with respect to the level of dose bias. In a second part, he discusses the different techniques used for the dosimetric control of new radiotherapy methods (intensity-modulated radiation therapy, tomo-therapy) for which film dosimetry is applied. He also evokes the development of new phantoms and the development of a method for the dosimetric control of proton beams

  11. 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

  12. Woven TPS – A Revolutionary Approach to Tailorable TPS Design & Manufacturing for Thermal Management Systems & Entry, Descent & Landing Systems

    Data.gov (United States)

    National Aeronautics and Space Administration — The thermal protection material system (TPS) is the barrier that protects the space vehicle from atmospheric entry heating. Woven TPS is a concept that leverages the...

  13. Clinical radionuclide therapy dosimetry: the quest for the "Holy Gray".

    NARCIS (Netherlands)

    Brans, B.; Bodei, L.; Giammarile, F.; Linden, O.; Luster, M.; Oyen, W.J.G.; Tennvall, J.

    2007-01-01

    INTRODUCTION: Radionuclide therapy has distinct similarities to, but also profound differences from external radiotherapy. REVIEW: This review discusses techniques and results of previously developed dosimetry methods in thyroid carcinoma, neuro-endocrine tumours, solid tumours and lymphoma. In each

  14. Testing of Advanced Conformal Ablative TPS

    Science.gov (United States)

    Gasch, Matthew; Agrawal, Parul; Beck, Robin

    2013-01-01

    In support of the CA250 project, this paper details the results of a test campaign that was conducted at the Ames Arcjet Facility, wherein several novel low density thermal protection (TPS) materials were evaluated in an entry like environment. The motivation for these tests was to investigate whether novel conformal ablative TPS materials can perform under high heat flux and shear environment as a viable alternative to rigid ablators like PICA or Avcoat for missions like MSL and beyond. A conformable TPS over a rigid aeroshell has the potential to solve a number of challenges faced by traditional rigid TPS materials (such as tiled Phenolic Impregnated Carbon Ablator (PICA) system on MSL, and honeycomb-based Avcoat on the Orion Multi Purpose Crew Vehicle (MPCV)). The compliant (high strain to failure) nature of the conformable ablative materials will allow better integration of the TPS with the underlying aeroshell structure and enable monolithic-like configuration and larger segments to be used in fabrication.A novel SPRITE1 architecture, developed by the researchers at NASA Ames was used for arcjet testing. This small probe like configuration with 450 spherecone, enabled us to test the materials in a combination of high heat flux, pressure and shear environment. The heat flux near the nose were in the range of 500-1000 W/sq cm whereas in the flank section of the test article the magnitudes were about 50 of the nose, 250-500W/sq cm range. There were two candidate conformable materials under consideration for this test series. Both test materials are low density (0.28 g/cu cm) similar to Phenolic Impregnated Carbon Ablator (PICA) or Silicone Impregnated Refractory Ceramic Ablator (SIRCA) and are comprised of: A flexible carbon substrate (Carbon felt) infiltrated with an ablative resin system: phenolic (Conformal-PICA) or silicone (Conformal-SICA). The test demonstrated a successful performance of both the conformable ablators for heat flux conditions between 50

  15. Dose delivery verification and accuracy assessment of stereotaxy in stereotactic radiotherapy and radiosurgery

    International Nuclear Information System (INIS)

    Pelagade, S.M.; Bopche, T.T.; Namitha, K.; Munshi, M.; Bhola, S.; Sharma, H.; Patel, B.K.; Vyas, R.K.

    2008-01-01

    The outcome of stereotactic radiotherapy (SRT) and stereotactic radiosurgery (SRS) in both benign and malignant tumors within the cranial region highly depends on precision in dosimetry, dose delivery and the accuracy assessment of stereotaxy associated with the unit. The frames BRW (Brown-Roberts-Wells) and GTC (Gill- Thomas-Cosman) can facilitate accurate patient positioning as well as precise targeting of tumours. The implementation of this technique may result in a significant benefit as compared to conventional therapy. As the target localization accuracy is improved, the demand for treatment planning accuracy of a TPS is also increased. The accuracy of stereotactic X Knife treatment planning system has two components to verify: (i) the dose delivery verification and the accuracy assessment of stereotaxy; (ii) to ensure that the Cartesian coordinate system associated is well established within the TPS for accurate determination of a target position. Both dose delivery verification and target positional accuracy affect dose delivery accuracy to a defined target. Hence there is a need to verify these two components in quality assurance protocol. The main intention of this paper is to present our dose delivery verification procedure using cylindrical wax phantom and accuracy assessment (target position) of stereotaxy using Geometric Phantom on Elekta's Precise linear accelerator for stereotactic installation

  16. Aerodynamic and Aerothermal TPS Instrumentation Reference Guide

    Science.gov (United States)

    Woollard, Bryce A.; Braun, Robert D.; Bose, Deepack

    2016-01-01

    The hypersonic regime of planetary entry combines the most severe environments that an entry vehicle will encounter with the greatest amount of uncertainty as to the events unfolding during that time period. This combination generally leads to conservatism in the design of an entry vehicle, specifically that of the thermal protection system (TPS). Each planetary entry provides a valuable aerodynamic and aerothermal testing opportunity; the utilization of this opportunity is paramount in better understanding how a specific entry vehicle responds to the demands of the hypersonic entry environment. Previous efforts have been made to instrument entry vehicles in order to collect data during the entry period and reconstruct the corresponding vehicle response. The purpose of this paper is to cumulatively document past TPS instrumentation designs for applicable planetary missions, as well as to list pertinent results and any explainable shortcomings.

  17. 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)

  18. Application of numerical analysis methods to thermoluminescence dosimetry

    International Nuclear Information System (INIS)

    Gomez Ros, J. M.; Delgado, A.

    1989-01-01

    This report presents the application of numerical methods to thermoluminescence dosimetry (TLD), showing the advantages obtained over conventional evaluation systems. Different configurations of the analysis method are presented to operate in specific dosimetric applications of TLD, such as environmental monitoring and mailed dosimetry systems for quality assurance in radiotherapy facilities. (Author) 10 refs

  19. Introduction to radiological physics and radiation dosimetry

    CERN Document Server

    Attix, Frank Herbert

    2004-01-01

    A straightforward presentation of the broad concepts underlying radiological physics and radiation dosimetry for the graduate-level student. Covers photon and neutron attenuation, radiation and charged particle equilibrium, interactions of photons and charged particles with matter, radiotherapy dosimetry, as well as photographic, calorimetric, chemical, and thermoluminescence dosimetry. Includes many new derivations, such as Kramers X-ray spectrum, as well as topics that have not been thoroughly analyzed in other texts, such as broad-beam attenuation and geometrics, and the reciprocity theorem

  20. Aerothermal Testing of Woven TPS Ablative Materials

    Science.gov (United States)

    Stackpoole, Mairead; Feldman, Jay; Olson, Michael; Venkatapathy, Ethiraj

    2012-01-01

    Woven Thermal Protection Systems (WTPS) is a new TPS concept that is funded by NASAs Office of the Chief Technologist (OCT) Game Changing Division. The WTPS project demonstrates the potential for manufacturing a variety of TPS materials capable of wide ranging performances demanded by a spectrum of solar system exploration missions. Currently, missions anticipated to encounter heat fluxes in the range of 1500 4000 Watts per square centimeter are limited to using one proven material fully dense Carbon Phenolic. However, fully dense carbon phenolic is only mass efficient at heat fluxes greater than 4000 Watts per square centimeter, and current mission designs suffer this mass inefficiency for lack of an alternative mid-density TPS. WTPS not only bridges this gap but also offers a replacement for carbon phenolic, which itself requires a significant and costly redevelopment effort to re-establish its capability for use in the high heat flux missions recently prioritized in the NRC Decadal survey, including probe missions to Venus, Saturn and Neptune. This poster will summarize some recent arc jet testing to evaluate the performance of WTPS. Both mid density and fully dense WTPS test results will be presented and results compared to heritage carbon phenolic where applicable.

  1. The influence of non-radiation induced ESR background signal from paraffin-alanine probes for dosimetry in the radiotherapy dose range

    International Nuclear Information System (INIS)

    Wieser, A.; Lettau, C.; Fill, U.; Regulla, D.F.

    1993-01-01

    The yield of radicals induced by ionizing radiation in the amino acid alanine and its quantification by ESR spectroscopy has proven excellent reproducibility. Those radicals trapped in the crystal lattice are prevented from recombination providing a thermally very stable system. This allows alanine to be applied as a transfer dosemeter. With paraffin-alanine probes ESR dosimetry can be performed with a standard deviation of ± 0.5% in the dose range from 20 Gy up to 100 kGy. At 1 Gy dose level the error increases to ± 6%. This dose level is three orders of magnitude higher than the calculated detection threshold for alanine with modern X-band ESR spectrometers. It was found that the poor standard deviation at the 1 Gy dose level, is not mainly produced by a bad signal-to-noise ratio but by a variable non-radiation induced ESR background signal from the alanine probes within a batch. In the present study the main sources of error for ESR dosimetry in the dose range below 20 Gy were analyzed. The influences of the production process, UV light and humidity upon the ESR background signal from paraffin-alanine probes were investigated. Measurements are shown indicating a second stable structure of the alanine radical at room temperature. (author)

  2. Dosimetry methods

    DEFF Research Database (Denmark)

    McLaughlin, W.L.; Miller, A.; Kovacs, A.

    2003-01-01

    Chemical and physical radiation dosimetry methods, used for the measurement of absorbed dose mainly during the practical use of ionizing radiation, are discussed with respect to their characteristics and fields of application.......Chemical and physical radiation dosimetry methods, used for the measurement of absorbed dose mainly during the practical use of ionizing radiation, are discussed with respect to their characteristics and fields of application....

  3. MRI-guided single fraction ablative radiotherapy for early-stage breast cancer: a brachytherapy versus volumetric modulated arc therapy dosimetry study.

    Science.gov (United States)

    Charaghvandi, Ramona K; den Hartogh, Mariska D; van Ommen, Anne-Mar L N; de Vries, Wilfred J H; Scholten, Vincent; Moerland, Marinus A; Philippens, Mariëlle E P; Schokker, Rogier I; van Vulpen, Marco; van Asselen, Bram; van den Bongard, Desirée H J G

    2015-12-01

    A radiosurgical treatment approach for early-stage breast cancer has the potential to minimize the patient's treatment burden. The dosimetric feasibility for single fraction ablative radiotherapy was evaluated by comparing volumetric modulated arc therapy (VMAT) with an interstitial multicatheter brachytherapy (IMB) approach. The tumors of 20 patients with early-stage breast cancer were delineated on a preoperative contrast-enhanced planning CT-scan, co-registered with a contrast-enhanced magnetic resonance imaging (MRI), both in radiotherapy supine position. A dose of 15 Gy was prescribed to the planned target volume of the clinical target volume (PTVCTV), and 20 Gy integrated boost to the PTV of the gross tumor volume (PTVGTV). Treatment plans for IMB and VMAT were optimized for adequate target volume coverage and minimal organs at risk (OAR) dose. The median PTVGTV/CTV receiving at least 95% of the prescribed dose was ⩾99% with both techniques. The median PTVCTV unintentionally receiving 95% of the prescribed PTVGTV dose was 65.4% and 4.3% with IMB and VMAT, respectively. OAR doses were comparable with both techniques. MRI-guided single fraction radiotherapy with an integrated ablative boost to the GTV is dosimetrically feasible with both techniques. We perceive IMB less suitable for clinical implementation due to PTVCTV overdosage. Future studies have to confirm the clinical feasibility of the single fraction ablative approach. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

  4. SU-F-T-17: A Feasibility Study for the Transit Dosimetry with a Glass Dosimeter in Brachytherapy

    Energy Technology Data Exchange (ETDEWEB)

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

    2016-06-15

    Purpose: Confirming the dose delivered to a patient is important to make sure the treatment quality and safety of the radiotherapy. Measuring a transit dose of the patient during the radiotherapy could be an interesting way to confirm the patient dose. In this study, we evaluated the feasibility of the transit dosimetry with a glass dosimeter in brachytherapy. Methods: We made a phantom that inserted the glass dosimeters and placed under patient lying on a couch for cervix cancer brachytherapy. The 18 glass dosimeters were placed in the phantom arranged 6 per row. A point putting 1cm vertically from the source was prescribed as 500.00 cGy. Solid phantoms of 0, 2, 4, 6, 8, 10 cm were placed between the source and the glass dosimeter. The transit dose was measured each thickness using the glass dosimeters and compared with a treatment planning system (TPS). Results: When the transit dose was smaller than 10 cGy, the average of the differences between measured values and calculated values by TPS was 0.50 cGy and the standard deviation was 0.69 cGy. If the transit dose was smaller than 100 cGy, the average of the error was 1.67 ± 4.01 cGy. The error to a point near the prescription point was −14.02 cGy per 500.00 cGy of the prescription dose. Conclusion: The distances from the sources to skin of the patient generally are within 10 cm for cervix cancer cases in brachytherapy. The results of this preliminary study showed the probability of the glass dosimeter as the transit dosimeter in brachytherapy.

  5. Modeling of a planning system in radiotherapy and Nuclear Medicine using the MCNP6 code

    International Nuclear Information System (INIS)

    Massicano, Felipe

    2015-01-01

    Cancer therapy has many branches and one of them is the use of radiation sources as treatment leading method. Radiotherapy and nuclear medicine are examples of these treatment types. For using the ionization radiation as main tool for the therapy, there is the need of crafting many treatment simulation in order to maximum the tumoral tissue dose without surpass the dose limit in health tissue surrounding. Treatment planning systems (TPS) are systems which have the purpose of simulating these therapy types. Nuclear medicine and radiotherapy have many distinct features linked to the therapy mode and consequently they have different TPS destined for each. The radiotherapy TPS is more developed than the nuclear medicine TPS and by that reason the development of a TPS that was similar to the radiotherapy TPS, but enough generic for include other therapy types, it will contribute with significant advances in nuclear medicine and in others therapy types with radiation. Based on this, the goal of work was to model a TPS that utilizes the Monte Carlo N-Particle Transport code (MCNP6) in order to simulate radiotherapy therapy, nuclear medicine therapy and with potential for simulating other therapy types too. The result of this work was the creation of a Framework in Java language, object oriented, named IBMC which will assist in the development of new TPS with MCNP6 code. The IBMC allowed to develop rapidly and easily TPS for radiotherapy and nuclear medicine and the results were validated with systems already consolidated. The IBMC showed high potential for developing TPS by new therapy types. (author)

  6. 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

  7. 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.)

  8. Characterization of thermoluminescent crystals (LIF:MG.TI) for dosimetry in patients of radiotherapy; Caracterizacion de cristales termoluminiscentes (LIF:MG.TI) para dosimetria de pacientes de radioterapia

    Energy Technology Data Exchange (ETDEWEB)

    Valderrama, Z.; Machado, H.; Plazas, M.

    2006-07-01

    The dosimetry allows us to verify the dose received by a patients, detecting a possible sub or over dosage at the beginning of the Radiation treatment or during the course of it. In such a way, those corrections can be made on subsequent fractions. This contributes to the evaluation of uncertainties on the planning and delivery of dose to the target volume and organs at risk. At the same time, it allows to detect possible abnormalities on the operation of radiation emitting equipment. The purpose of this work is to show the viability of a quality assurance routine using a TLD system. To reach to goal, TLD detectors response characteristics were determined by means of a cobalt 60 beam. (Author)

  9. Development of manual procedures for care of pregnant patients in radiotherapy service; Desarrollo de manual de procedimentos para atencion de pacientes embarazadas en servicio de radioterapia

    Energy Technology Data Exchange (ETDEWEB)

    Scarabino, M.L., E-mail: maliscarabino@gmail.com [Hospital Italiano de Buenos Aires (HIBA), Buenos Aires (Argentina); Ruggeri, R.M.; Colombo, S.; Mairal, L.; Sardi, M.E., E-mail: ricardoruggeri@gmail.com [Mevaterapia Centro Medico, Buenos Aires (Argentina)

    2013-11-01

    The work involves the creation of a manual of procedures for the care of pregnant patients in a radiotherapy center in which each instance of treatment is included, from the obstetrician-oncology comprehensive assessment during admission to establishing controls newborn and its subsequent development in multidisciplinary team. For the preparation of the manual had to design an anthropomorphic phantom that resembles a pregnant woman, which was used to carry out internal and external dosimetry. In turn imparted calculations fetal doses using TPS, imaging tests with MRI, avoiding the use of the tomograph and adapted to the resonator involved were carried immobilizer. All experiences and progress made during the treated cases are introduced in the procedures manual, making it a dynamic tool for continuous improvement for the institution.

  10. Dosimetry of ionising radiation in modern radiation oncology

    Science.gov (United States)

    Kron, Tomas; Lehmann, Joerg; Greer, Peter B.

    2016-07-01

    Dosimetry of ionising radiation is a well-established and mature branch of physical sciences with many applications in medicine and biology. In particular radiotherapy relies on dosimetry for optimisation of cancer treatment and avoidance of severe toxicity for patients. Several novel developments in radiotherapy have introduced new challenges for dosimetry with small and dynamically changing radiation fields being central to many of these applications such as stereotactic ablative body radiotherapy and intensity modulated radiation therapy. There is also an increasing awareness of low doses given to structures not in the target region and the associated risk of secondary cancer induction. Here accurate dosimetry is important not only for treatment optimisation but also for the generation of data that can inform radiation protection approaches in the future. The article introduces some of the challenges and highlights the interdependence of dosimetric calculations and measurements. Dosimetric concepts are explored in the context of six application fields: reference dosimetry, small fields, low dose out of field, in vivo dosimetry, brachytherapy and auditing of radiotherapy practice. Recent developments of dosimeters that can be used for these purposes are discussed using spatial resolution and number of dimensions for measurement as sorting criteria. While dosimetry is ever evolving to address the needs of advancing applications of radiation in medicine two fundamental issues remain: the accuracy of the measurement from a scientific perspective and the importance to link the measurement to a clinically relevant question. This review aims to provide an update on both of these.

  11. Environmental dosimetry

    International Nuclear Information System (INIS)

    Gold, R.

    1977-01-01

    For more than 60 years, natural radiation has offered broad opportunities for basic research as evidenced by many fundamental discoveries. Within the last decade, however, dramatic changes have occurred in the motivation and direction of this research. The urgent need for economical energy sources entailing acceptably low levels of environmental impact has compelled the applied aspects of our radiation environment to become overriding considerations. It is within this general framework that state-of-the-art environmental dosimetry techniques are reviewed. Although applied motivation and relevance underscores the current milieu for both reactor and environmental dosimetry, a perhaps even more unifying force is the broad similarity of reactor and environmental radiation fields. In this review, a comparison of these two mixed radiation fields is presented stressing the underlying similarities that exist. On this basis, the evolution of a strong inner bond between dosimetry methods for both reactor and environmental radiation fields is described. The existence of this bond will be illustrated using representative examples of observed spectra. Dosimetry methods of particularly high applicability for both of these fields are described. Special emphasis is placed on techniques of high sensitivity and absolute accuracy which are capable of resolving the components of these mixed radiation fields

  12. Evaluation of detector array technology for the verification of advanced intensity-modulated radiotherapy

    Science.gov (United States)

    Hussien, Mohammad

    Purpose: Quality assurance (QA) for intensity modulated radiotherapy (IMRT) has evolved substantially. In recent years, various ionization chamber or diode detector arrays have become commercially available, allowing pre-treatment absolute dose verification with near real-time results. This has led to a wide uptake of this technology to replace point dose and film dosimetry and to facilitate QA streamlining. However, arrays are limited by their spatial resolution giving rise to concerns about their response to clinically relevant deviations. The common factor in all commercial array systems is the reliance on the gamma index (γ) method to provide the quantitative evaluation of the measured dose distribution against the Treatment Planning System (TPS) calculated dose distribution. The mathematical definition of the gamma index presents computational challenges that can cause a variation in the calculation in different systems. The purpose of this thesis was to evaluate the suitability of detector array systems, combined with their implementation of the gamma index, in the verification and dosimetry audit of advanced IMRT. Method: The response of various commercial detector array systems (Delta4®, ArcCHECK®, and the PTW 2D-Array seven29™ and OCTAVIUS II™ phantom combination, Gafchromic® EBT2 and composite EPID measurements) to simulated deliberate changes in clinical IMRT and VMAT plans was evaluated. The variability of the gamma index calculation in the different systems was also evaluated by comparing against a bespoke Matlab-based gamma index analysis software. A novel methodology for using a commercial detector array in a dosimetry audit of rotational radiotherapy was then developed. Comparison was made between measurements using the detector array and those performed using ionization chambers, alanine and radiochromic film. The methodology was developed as part of the development of a national audit of rotational radiotherapy. Ten cancer centres were

  13. Overexposure of radiotherapy patients in Panama: Dosimetric aspects

    International Nuclear Information System (INIS)

    Borras, C.; Rudder, D.; Amer, A.

    2001-01-01

    In March 2001, after treatment received in the National Oncological Institute of Panama, 28 patients over reacted due to a radiation overdose calculated by mistake through the algorithm of a Computerized Therapy Planning System (TPS) with Radiotherapy. Medical Physicists planned a four blocks simultaneous digitization, even though the TPS briefings only allowed the digitization of one block per time, but the software didn't notified that the procedure was not authorized, producing serious medical consequences for all the patients [es

  14. A study to compare the motorised wedge output factor of an elekta synergy linear accelerator with reference data (TPS Data)

    International Nuclear Information System (INIS)

    Akosah, Kinsley

    2016-07-01

    For external beam radiotherapy treatments, high doses are delivered to the cancerous cell. Accuracy and precision of dose delivery are primary requirements for effective and efficient cancer treatment. The dose delivered to the patient might not be uniform and therefore need to be compensated for. In treatment these inhomogeneities are taken care of by using wedge filters and incorporating wedge factors in the Treatment Planning System. Computer controlled wedges were alternatives introduced by different manufacturers of which Motorized wedges (MW) is one of them. The MW was introduced by ELEKTA and this helps to overcome some of the shortcomings of physical wedges. The objectives of this study were to measure MW output factors for 6 MV and 15 MV photon energies for an ELEKTA Synergy. Secondly, to compare the results of MWOF obtained to that of the treatment planning system data. The Motorized Wedge Output Factors (MWOF) were measured for the ELEKTA Synergy for both 6 MV and 15 MV photon energies. With the help of PMMA solid water slabs phantom, the Elekta synergy, thermometer, barometer, PTW farmer type ionization chamber 30010 charges were collected at 100 cm source to surface distance for various square field sizes from 5x5 cm to 30x30 cm and depth of 1.5 cm and 2.5 cm for 6 MV and 15 MV photon energies. Comparing the results with the TPS data, an excellent agreement was found for 6 MV MWOF, with the percentage differences ranging from 0.03% to 1.50%, with a mean of 0.03%. The coefficient of variation of MWOF ranged from 0.023% to 1.07% and 0.001% to 12.89% for the two beams (6 MV and 15 MV) respectively. The relative differences between the calculated and the measured MWOFs increases with field size. In conclusion, there was general agreement between the calculated and measured MWOFs. The consistency of values provide further support that a standard dataset of photon and electron dosimetry could be established as a guide for future commissioning, beam modeling

  15. Remote Cherenkov Imaging Based Quality Assurance of a Magnetic Resonance Image Guided Radiotherapy System.

    Science.gov (United States)

    Andreozzi, Jacqueline M; Mooney, Karen E; Brůža, Petr; Curcuru, Austen; Gladstone, David J; Pogue, Brian W; Green, Olga

    2018-04-16

    Tools to perform regular quality assurance of magnetic resonance image-guided radiotherapy (MR-IGRT) systems should ideally be independent of interference from the magnetic fields. Remotely acquired optical Cherenkov imaging-based dosimetry measurements in water were investigated for this purpose, comparing measures of dose accuracy, temporal dynamics, and overall integrated IMRT delivery. A 40x30.5x37.5cm 3 water tank doped with 1g/L of quinine sulfate was imaged using an intensified charge coupled device (ICCD) to capture the Cherenkov emission while being irradiated by a commercial MR-IGRT system (ViewRay ™ ). The ICCD was placed down-bore at the end of the couch, 4m from treatment isocenter and behind the 5-Gauss line of the 0.35-T MRI. After establishing optimal camera acquisition settings, square beams of increasing size (4.2x4.2cm 2 , 10.5x10.5 cm 2 , and 14.7x14.7cm 2 ) were imaged at 0.93 frames per second, from an individual cobalt-60 treatment head, to develop projection measures related to percent depth dose (PDD) curves and cross-beam profiles (CPB). These Cherenkov-derived measurements were compared to ionization chamber (IC) and radiographic film dosimetry data, as well as simulation data from the treatment planning system (TPS). An intensity modulated radiotherapy (IMRT) commissioning plan from AAPM TG-119 (C4:C-Shape) was also imaged at 2.1 frames per second, and the single linear sum image from 509 seconds of plan delivery was compared to the dose volume prediction generated by the TPS using gamma index analysis. Analysis of standardized test target images (1024x1024pixels) yielded a pixel resolution of 0.37mm/pixel. The beam width measured from the Cherenkov image-generated projection CBPs was within 1mm accuracy when compared to film measurements for all beams. The 502 point measurements (i.e. pixels) of the Cherenkov image-based projection percent depth dose curves (pPDDs) were compared to pPDDs simulated by the treatment planning system (TPS

  16. Osteoradionecrosis following treatment for head and neck cancer and the effect of radiotherapy dosimetry: the Guy's and St Thomas' Head and Neck Cancer Unit experience.

    Science.gov (United States)

    De Felice, Francesca; Thomas, Christopher; Patel, Vinod; Connor, Steve; Michaelidou, Andriana; Sproat, Chris; Kwok, Jerry; Burke, Mary; Reilly, Damien; McGurk, Mark; Simo, Ricard; Lyons, Andrew; Oakley, Richard; Jeannon, Jean-Pierre; Lei, Mary; Urbano, Teresa Guerrero

    2016-07-01

    To analyze clinical features, dosimetric parameters, and outcomes of osteoradionecrosis (ORN). Thirty-six patients with ORN who had been previously treated with radiotherapy (RT) were retrospectively identified between January 2009 and April 2014. ORN volumes were contoured on planning computed tomography (CT) scans. Near maximum dose (D2%), minimum dose (Dmin), mean dose (Dmean), and percentage of bone volume receiving 50 Gy (V50) were examined. Clinical and dosimetric variables were considered to compare ORN resolution versus ORN persistence. Median interval time from end of RT to development of ORN was 6 months. Of the ORN cases, 61% were located in the mandible. Dmean to affected bone was 57.6 Gy, and 44% had a D2% 65 Gy or greater. Smoking was associated with ORN persistence on univariate analysis, but no factors were found to impact ORN resolution or progression on logistic regression. Prevention strategies for ORN development should be prioritized. Dose-volume parameters could have a role in preventing ORN. Copyright © 2016 Elsevier Inc. All rights reserved.

  17. Thermoluminescence in medical dosimetry; Termoluminiscencia en dosimetria medica

    Energy Technology Data Exchange (ETDEWEB)

    Rivera, T., E-mail: trivera@ipn.mx [IPN, Centro de Investigacion en Ciencia Aplicada y Tecnologia Avanzada, Av. Legaria 694, Col. Irrigacion, 11500 Mexico D. F. (Mexico)

    2011-10-15

    The dosimetry by thermoluminescence (Tl) is applied in the entire world for the dosimetry of ionizing radiations specially to personal and medical dosimetry. This dosimetry method has been very interesting for measures in vivo because the Tl dosimeters have the advantage of being very sensitive in a very small volume and they are also equivalent to tissue and they do not need additional accessories (for example, cable, electrometer, etc.) The main characteristics of the diverse Tl materials to be used in the radiation measures and practical applications are: the Tl curve, the share homogeneity, the signal stability after the irradiation, precision and exactitude, the response in function with the dose and the energy influence. In this work a brief summary of the advances of the radiations dosimetry is presented by means of the thermally stimulated luminescence and its application to the dosimetry in radiotherapy. (Author)

  18. Neutron personnel dosimetry

    International Nuclear Information System (INIS)

    Griffith, R.V.

    1981-01-01

    The current state-of-the-art in neutron personnel dosimetry is reviewed. Topics covered include dosimetry needs and alternatives, current dosimetry approaches, personnel monitoring devices, calibration strategies, and future developments

  19. Development of virtual CT DICOM images of patients with tumors: application for TPS and Monte Carlo dose evaluation

    International Nuclear Information System (INIS)

    Milian, F. M.; Attili, A.; Russo, G; Marchetto, F.; Cirio, R.; Bourhaleb, F.

    2013-01-01

    A novel procedure for the generation of a realistic virtual Computed Tomography (CT) image of a patient, using the advanced Boundary RE Presentation (BREP)-based model MASH, has been implemented. This method can be used in radiotherapy assessment. It is shown that it is possible to introduce an artificial cancer, which can be modeled using mesh surfaces. The use of virtual CT images based on BREP models presents several advantages with respect to CT images of actual patients, such as automation, control and flexibility. As an example, two artificial cases, namely a brain and a prostate cancer, were created through the generation of images and tumor/organ contours. As a secondary objective, the described methodology has been used to generate input files for treatment planning system (TPS) and Monte Carlo code dose evaluation. In this paper, we consider treatment plans generated assuming a dose delivery via an active proton beam scanning performed with the INFN-IBA TPS kernel. Additionally, Monte Carlo simulations of the two treatment plans were carried out with GATE/GEANT4. The work demonstrates the feasibility of the approach based on the BREP modeling to produce virtual CT images. In conclusion, this study highlights the benefits in using digital phantom model capable of representing different anatomical structures and varying tumors across different patients. These models could be useful for assessing radiotherapy treatment planning systems (TPS) and computer simulations for the evaluation of the adsorbed dose. (author)

  20. Development of targeted radiotherapy systems

    International Nuclear Information System (INIS)

    Ferro, Guillermina; Villarreal, Jose E.; Garcia, Laura; Tendilla, Jose I.; Paredes, Lydia; Murphy, Consuelo A.; Pedraza, Martha

    2001-01-01

    Conventional or external beam radiotherapy, has been a viable alternative for cancer treatment. Although this technique is effective, its use is limited if the patient has multiple malignant lesions (metastases). An alternative approach is based on the design of radiopharmaceuticals that, to be administered in the patient, are directed specifically toward the target cell producing a selective radiation delivery. This treatment is known as targeted radiotherapy. We have summarized and discussed some results related to our investigations on the development of targeted radiotherapy systems, including aspects of internal dosimetry

  1. SU-D-213-03: Towards An Optimized 3D Scintillation Dosimetry Tool for Quality Assurance of Dynamic Radiotherapy Techniques

    Energy Technology Data Exchange (ETDEWEB)

    Rilling, M [Département de physique, de génie physique et d’optique, Université Laval, Quebec City, QC (Canada); Centre de Recherche sur le Cancer, Hôtel-Dieu de Québec, Quebec City, QC (Canada); Département de radio-oncologie, CHU de Québec, Quebec City, QC (Canada); Center for Optics, Photonics and Lasers, Université Laval, Quebec City, QC, CA (Canada); Goulet, M [Département de radio-oncologie, CHU de Québec, Quebec City, QC (Canada); Thibault, S [Département de physique, de génie physique et d’optique, Université Laval, Quebec City, QC (Canada); Center for Optics, Photonics and Lasers, Université Laval, Quebec City, QC, CA (Canada); Archambault, L [Département de physique, de génie physique et d’optique, Université Laval, Quebec City, QC (Canada); Centre de Recherche sur le Cancer, Hôtel-Dieu de Québec, Quebec City, QC (Canada); Département de radio-oncologie, CHU de Québec, Quebec City, QC (Canada)

    2015-06-15

    Purpose: The purpose of this work is to simulate a multi-focus plenoptic camera used as the measuring device in a real-time three-dimensional scintillation dosimeter. Simulating and optimizing this realistic optical system will bridge the technological gap between concept validation and a clinically viable tool that can provide highly efficient, accurate and precise measurements for dynamic radiotherapy techniques. Methods: The experimental prototype, previously developed for proof of concept purposes, uses an off-the-shelf multi-focus plenoptic camera. With an array of interleaved microlenses of different focal lengths, this camera records spatial and angular information of light emitted by a plastic scintillator volume. The three distinct microlens focal lengths were determined experimentally for use as baseline parameters by measuring image-to-object magnification for different distances in object space. A simulated plenoptic system was implemented using the non-sequential ray tracing software Zemax: this tool allows complete simulation of multiple optical paths by modeling interactions at interfaces such as scatter, diffraction, reflection and refraction. The active sensor was modeled based on the camera manufacturer specifications by a 2048×2048, 5 µm-pixel pitch sensor. Planar light sources, simulating the plastic scintillator volume, were employed for ray tracing simulations. Results: The microlens focal lengths were determined to be 384, 327 and 290 µm. A realistic multi-focus plenoptic system, with independently defined and optimizable specifications, was fully simulated. A f/2.9 and 54 mm-focal length Double Gauss objective was modeled as the system’s main lens. A three-focal length hexagonal microlens array of 250-µm thickness was designed, acting as an image-relay system between the main lens and sensor. Conclusion: Simulation of a fully modeled multi-focus plenoptic camera enables the decoupled optimization of the main lens and microlens

  2. In vivo Tl dosimetry for the quality control in Radiotherapy with {sup 60} Co and brachytherapy of low dose rate; Dosimetria Tl in vivo para el control de calidad en Radioterapia con {sup 60} Co y Braquiterapia de baja tasa de dosis

    Energy Technology Data Exchange (ETDEWEB)

    Velez, G.; Bustos, S.; Balmaceda, O.; Gutierrez, S.; Ferraris, M. [Servicio de Radioterapia, Hospital San Roque. Rosario de Santa Fe 374. CP 5000. Cordoba (Argentina)

    1998-12-31

    In vivo dosimetry is used every time with more frequency as a valuable tool for the quality control in Radiotherapy. The measurements of input and output doses provide us information about the technique accuracy or the treatment procedure used; likewise the dose measurement which rectum or bladder receive in gynecologic implants contribute to the improving and adjusting the procedures in brachytherapy. Besides, it may be identify systematic errors in particular situations which allow to optimize the treatment and to minimize errors. It was realized a study at the Radiotherapy service in San Roque Hospital (Cordoba) to control the procedures used in the treatment of distinct oncologic pathologies. Its were selected patients, which were realized the routine planning with the planning system of computerized treatments Prowess 3000, that later its were controlled with In vivo thermoluminescent dosimetry using the Ceprocor Services (Cordoba). Its were realized dose skin measurements in treatments of mammary gland, pelvis, thorax, head and neck and it were measured doses in body cavities, as oral cavity, rectum, esophagus, etc. arranging the TLD inside special catheters. In the case of dose skin, the dosemeters were arranged in acrylic porta-dosemeters, at pairs, which later they were enveloped and sealed. It was founded a very good agreement among the In vivo measurements and the predicted by the planner. In some cases, the control allows to modify the treatment for to avoid over or sub dosages of the distinct organs affected by the radiation field. (Author)

  3. Advances in electron dosimetry of irregular fields

    International Nuclear Information System (INIS)

    Mendez V, J.

    1998-01-01

    In this work it is presented an advance in Electron dosimetry of irregular fields for beams emitted by linear accelerators. At present diverse methods exist which are coming to apply in the Radiotherapy centers. In this work it is proposed a method for irregular fields dosimetry. It will be allow to calculate the dose rate absorbed required for evaluating the time for the treatment of cancer patients. Utilizing the results obtained by the dosimetric system, it has been possible to prove the validity of the method describe for 12 MeV energy and for square field 7.5 x 7.5 cm 2 with percentile error less than 1 % . (Author)

  4. Skin Dosimetry in Breast Teletherapy on a Phantom Anthropomorphic and Anthropometric Phantom

    International Nuclear Information System (INIS)

    Batista Nogueira, Luciana; Lemos Silva, Hugo Leonardo; Donato da Silva, Sabrina; Passos Ribeiro Campos, Tarcisio

    2015-01-01

    This paper addresses the breast teletherapy dosimetry. The goal is to evaluate and compare absorbed doses in equivalent skin tissue, TE-skin, of an anthropomorphic and anthropometric breast phantom submitted to breast radiotherapy. The methodology involved the reproduction of a set of tomographic images of the phantom; the elaboration of conformational radiotherapy planning in the SOMAVISION and CadPlan (TPS) software; and the synthetic breast irradiation by parallel opposed fields in 3D conformal teletherapy at 6 MV linear accelerator Clinac-2100 C from VARIAN with prescribed dose (PD) of 180 cGy to the target volume (PTV), referent to the glandular tissue. Radiochromic films EBT2 were selected as dosimeters. Two independent calibration processes of films with solid water Gammex 457 plates and water filled box were produced. Curves of optical density (OD) versus absorbed dose were produced. Dosimeters were positioned in the external region of the breast phantom in contact with TE-skin, area of 4.0 cm 2 each. The irradiation process was prepared in duplicate to check the reproducibility of the technique. The radiochromic films were scanned and their response in RGB (Red, Green, Blue) analyzed by the ImageJ software. The optical density was obtained and converted to dose based on the calibration curves. Thus, the spatial dose distribution in the skin was reproduced. The absorbed doses measured on the radiochromic films in TE-skin showed values between upper and lower quadrants at 9 o'clock in the range of 54% of PD, between the upper and lower quadrants 3 o'clock in the range of 72% and 6 o'clock at the lower quadrant in the range of 68 % of PD. The values are ±64% (p <0.05) according to the TPS. It is concluded that the depth dose measured in solid water plates or water box reproduce equivalent dose values for both calibration processes of the radiochromic films. It was observed that the skin received doses ranging from 50% to 78% of the prescribed

  5. Skin Dosimetry in Breast Teletherapy on a Phantom Anthropomorphic and Anthropometric Phantom

    Energy Technology Data Exchange (ETDEWEB)

    Batista Nogueira, Luciana [Anatomy and Imaging Department, Federal University of Minas Gerais, Belo Horizonte (Brazil); Lemos Silva, Hugo Leonardo [Santa Casa Hospital, Belo Horizonte (Brazil); Donato da Silva, Sabrina; Passos Ribeiro Campos, Tarcisio [Nuclear Engineering Department, Federal University of Minas Gerais, Belo Horizonte (Brazil)

    2015-07-01

    This paper addresses the breast teletherapy dosimetry. The goal is to evaluate and compare absorbed doses in equivalent skin tissue, TE-skin, of an anthropomorphic and anthropometric breast phantom submitted to breast radiotherapy. The methodology involved the reproduction of a set of tomographic images of the phantom; the elaboration of conformational radiotherapy planning in the SOMAVISION and CadPlan (TPS) software; and the synthetic breast irradiation by parallel opposed fields in 3D conformal teletherapy at 6 MV linear accelerator Clinac-2100 C from VARIAN with prescribed dose (PD) of 180 cGy to the target volume (PTV), referent to the glandular tissue. Radiochromic films EBT2 were selected as dosimeters. Two independent calibration processes of films with solid water Gammex 457 plates and water filled box were produced. Curves of optical density (OD) versus absorbed dose were produced. Dosimeters were positioned in the external region of the breast phantom in contact with TE-skin, area of 4.0 cm{sup 2} each. The irradiation process was prepared in duplicate to check the reproducibility of the technique. The radiochromic films were scanned and their response in RGB (Red, Green, Blue) analyzed by the ImageJ software. The optical density was obtained and converted to dose based on the calibration curves. Thus, the spatial dose distribution in the skin was reproduced. The absorbed doses measured on the radiochromic films in TE-skin showed values between upper and lower quadrants at 9 o'clock in the range of 54% of PD, between the upper and lower quadrants 3 o'clock in the range of 72% and 6 o'clock at the lower quadrant in the range of 68 % of PD. The values are ±64% (p <0.05) according to the TPS. It is concluded that the depth dose measured in solid water plates or water box reproduce equivalent dose values for both calibration processes of the radiochromic films. It was observed that the skin received doses ranging from 50% to 78% of the

  6. Quantitative evaluation of patient-specific quality assurance using online dosimetry system

    Science.gov (United States)

    Jung, Jae-Yong; Shin, Young-Ju; Sohn, Seung-Chang; Min, Jung-Whan; Kim, Yon-Lae; Kim, Dong-Su; Choe, Bo-Young; Suh, Tae-Suk

    2018-01-01

    In this study, we investigated the clinical performance of an online dosimetry system (Mobius FX system, MFX) by 1) dosimetric plan verification using gamma passing rates and dose volume metrics and 2) error-detection capability evaluation by deliberately introduced machine error. Eighteen volumetric modulated arc therapy (VMAT) plans were studied. To evaluate the clinical performance of the MFX, we used gamma analysis and dose volume histogram (DVH) analysis. In addition, to evaluate the error-detection capability, we used gamma analysis and DVH analysis utilizing three types of deliberately introduced errors (Type 1: gantry angle-independent multi-leaf collimator (MLC) error, Type 2: gantry angle-dependent MLC error, and Type 3: gantry angle error). A dosimetric verification comparison of physical dosimetry system (Delt4PT) and online dosimetry system (MFX), gamma passing rates of the two dosimetry systems showed very good agreement with treatment planning system (TPS) calculation. For the average dose difference between the TPS calculation and the MFX measurement, most of the dose metrics showed good agreement within a tolerance of 3%. For the error-detection comparison of Delta4PT and MFX, the gamma passing rates of the two dosimetry systems did not meet the 90% acceptance criterion with the magnitude of error exceeding 2 mm and 1.5 ◦, respectively, for error plans of Types 1, 2, and 3. For delivery with all error types, the average dose difference of PTV due to error magnitude showed good agreement between calculated TPS and measured MFX within 1%. Overall, the results of the online dosimetry system showed very good agreement with those of the physical dosimetry system. Our results suggest that a log file-based online dosimetry system is a very suitable verification tool for accurate and efficient clinical routines for patient-specific quality assurance (QA).

  7. Functional characterization of nine Norway Spruce TPS genes and evolution of gymnosperm terpene synthases of the TPS-d subfamily.

    Science.gov (United States)

    Martin, Diane M; Fäldt, Jenny; Bohlmann, Jörg

    2004-08-01

    Constitutive and induced terpenoids are important defense compounds for many plants against potential herbivores and pathogens. In Norway spruce (Picea abies L. Karst), treatment with methyl jasmonate induces complex chemical and biochemical terpenoid defense responses associated with traumatic resin duct development in stems and volatile terpenoid emissions in needles. The cloning of (+)-3-carene synthase was the first step in characterizing this system at the molecular genetic level. Here we report the isolation and functional characterization of nine additional terpene synthase (TPS) cDNAs from Norway spruce. These cDNAs encode four monoterpene synthases, myrcene synthase, (-)-limonene synthase, (-)-alpha/beta-pinene synthase, and (-)-linalool synthase; three sesquiterpene synthases, longifolene synthase, E,E-alpha-farnesene synthase, and E-alpha-bisabolene synthase; and two diterpene synthases, isopimara-7,15-diene synthase and levopimaradiene/abietadiene synthase, each with a unique product profile. To our knowledge, genes encoding isopimara-7,15-diene synthase and longifolene synthase have not been previously described, and this linalool synthase is the first described from a gymnosperm. These functionally diverse TPS account for much of the structural diversity of constitutive and methyl jasmonate-induced terpenoids in foliage, xylem, bark, and volatile emissions from needles of Norway spruce. Phylogenetic analyses based on the inclusion of these TPS into the TPS-d subfamily revealed that functional specialization of conifer TPS occurred before speciation of Pinaceae. Furthermore, based on TPS enclaves created by distinct branching patterns, the TPS-d subfamily is divided into three groups according to sequence similarities and functional assessment. Similarities of TPS evolution in angiosperms and modeling of TPS protein structures are discussed.

  8. Oxidatively Stable Flexible Aerogel Composites for Reusable TPS, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — NASA?s Next Generation Launch Vehicle Technology Program has an interest in robust TPS materials with the highest level of thermal performance at the lowest possible...

  9. Fiber-Coupled Spectrometer for TPS Materials Project

    Data.gov (United States)

    National Aeronautics and Space Administration — EDA, Inc., in partnership with Penn State, has shown previously that the concept of embedding fiber optics within ablative TPS material has merit and should yield a...

  10. Fiber-Coupled Spectrometer for TPS Materials, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — Heat shield technology is a critical component of manned spaceflight. In particular, the new Crew Exploration Vehicle (CEV) requires thermal protection systems (TPS)...

  11. 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

  12. 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

  13. Contribution to the planning and dosimetry of photon beams applied to radiosurgery and stereotactic radiotherapy; Contribuicao ao planejamento e a dosimetria de feixes de fotons aplicados a radiocirurgia e a radioterapia estereotaxica

    Energy Technology Data Exchange (ETDEWEB)

    Santos, Walter Menezes

    2003-08-15

    Radiosurgery and stereotactic radiotherapy are irradiation techniques that use small diameter photon beams for treating intracranial lesions such as pituitary adenomas, acoustic tumors and arterio-venous malformations which are inaccessible for surgery. These treatment techniques are characterized by the use of very small radiation beams which deliver a precisely measured dose to the target volume, while sparing the surrounding healthy tissue. Treatment can be performed by using multiple {sup 60}Co gamma-ray sources (in the so-called 'Gamma Knife'), charged particles or X-ray beams produced by linear accelerators. The prescribed dose can be given in a single session or in multiple fractions, as in conventional radiotherapy. The success of the treatment depends, among other factors, of the accurate determination of the parameters that characterize the radiation beam produced by the equipment, as well as, of a well designed quality assurance program. In this study, the dosimetric parameters of a set of collimating cones of a Radionics{sup TM} treatment system applied to two 6 MV- photon beams (Clinac 600C - Varian{sup TM}, and Mevatron MD2 - Siemens{sup TM}) were evaluated by using a water filled PMMA simulator. Measurements were carried out for photon beam diameters ranging from 12.5 to 40.0 mm for the Clinac-600C and from 5.0 to 50.0 mm for the Mevatron MD2. The parameters were evaluated by using a parallel plate ionization chamber (Markus), Kodak X-Omat V dosimetric films, thermoluminescent dosemeters (Harschaw, TLD-100) and photodiodes. The maximum tissue-ratio, the off-axis profile and the output factors were determined and the results were compared to those reported elsewhere. A study of the dosimetric characteristics of some commercially available phototransistors was also carried out. The results showed that these electronic components can be successfully used for measuring the dosimetric parameters of small diameter photon beans used in

  14. INL Advanced Radiotherapy Research Program Annual Report 2004

    Energy Technology Data Exchange (ETDEWEB)

    James Venhuizen

    2005-06-01

    This report summarizes the activities and major accomplishments for the Idaho National Laboratory Advanced Radiotherapy Research Program for calendar year 2004. Topics covered include boron analysis in biological samples, computational dosimetry and treatment planning software development, medical neutron source development and characterization, and collaborative dosimetry studies at the RA-1 facility in Buenos Aires, Argentina.

  15. Two residues determine the product profile of the class II diterpene synthases TPS14 and TPS21 of Tripterygium wilfordii

    DEFF Research Database (Denmark)

    Hansen, Nikolaj Lervad; Nissen, Jakob N.; Hamberger, Björn Robert

    2017-01-01

    The medicinal plant Tripterygium wilfordii (Celastraceae) contains a pair of class II diterpene synthases (diTPS) of specialized labdane-type metabolism that, despite remarkably close homology, form strikingly different products. TwTPS21 catalyzes bicyclization of the linear C20 precursor...... to the understanding of structure-function relation in plant class II diTPSs and complements previous mutational studies of Arabidopsis ent-copalyl diphosphate synthase with additional examples from the specialized metabolism of T. wilfordii.......-directed mutagenesis, we generated a panel of six variants, where one, or both positions were exchanged between the enzymes. In coupled heterologous assays with a corresponding class I diTPS, TwTPS2, complete product interchange was observed in variants with both reciprocal mutations, while substitutions of either...

  16. Phantom dosimetry at 15 MV conformal radiation therapy

    International Nuclear Information System (INIS)

    Thompson, Larissa; Campos, Tarcisio P.R.

    2015-01-01

    The main goal of this work was to evaluate the spatial dose distribution into a tumor simulator inside a head phantom exposed to a 15MV 3D conformal radiation therapy in order to validate internal doses. A head and neck phantom developed by the Ionizing Radiation Research Group (NRI) was used on the experiments. Therapy Radiation planning (TPS) was performed based on those CT images, satisfying a 200 cGy prescribed dose split in three irradiation fields. The TPS assumed 97% of prescribed dose cover the prescribed treatment volume (PTV). Radiochromic films in a solid water phantom provided dose response as a function of optical density. Spatial dosimetric distribution was generated by radiochromic film samples inserted into tumor simulator and brain. The spatial dose profiles held 70 to 120% of the prescribed dose. In spite of the stratified profile, as opposed to the smooth dose profile from TPS, the tumor internal doses were within a 5% deviation from 214.4 cGy evaluated by TPS. 83.2% of the points with a gamma value of less than 1 (3%/3mm) for TPS and experimental values, respectively. At the tumor, a few dark spots in the film caused the appearance of outlier points in 13-15% of dose deviation percentage. As final conclusion, such dosimeter choice and the physical anthropomorphic and anthropometric phantom provided an efficient method for validating radiotherapy protocols. (author)

  17. Phantom dosimetry at 15 MV conformal radiation therapy

    International Nuclear Information System (INIS)

    Thompson, Larissa; Campos, Tarcisio P.R.; Dias, Humberto G.

    2013-01-01

    The main goal of this work was to evaluate the spatial dose distribution into a tumor simulator inside a head phantom exposed to a 15MV 3D conformal radiation therapy in order to validate internal doses. A head and neck phantom developed by the Ionizing Radiation Research Group (NRI) was used on the experiments. Therapy Radiation planning (TPS) was performed based on those CT images, satisfying a 200 cGy prescribed dose split in three irradiation fields. The TPS assumed 97% of prescribed dose cover the prescribed treatment volume (PTV). Radiochromic films in a solid water phantom provided dose response as a function of optical density. Spatial dosimetric distribution was generated by radiochromic film samples inserted into tumor simulator and brain. The spatial dose profiles held 70 to 120% of the prescribed dose. In spite of the stratified profile, as opposed to the smooth dose profile from TPS, the tumor internal doses were within a 5% deviation from 214.4 cGy evaluated by TPS. 83.2% of the points with a gamma value of less than 1 (3%/3mm) for TPS and experimental values, respectively. At the tumor, a few dark spots in the film caused the appearance of outlier points in 13-15% of dose deviation percentage. As final conclusion, such dosimeter choice and the physical anthropomorphic and anthropometric phantom provided an efficient method for validating radiotherapy protocols. (author)

  18. Phantom dosimetry at 15 MV conformal radiation therapy

    Energy Technology Data Exchange (ETDEWEB)

    Thompson, Larissa; Campos, Tarcisio P.R., E-mail: larissathompson@hotmail.com, E-mail: tprcampos@yahoo.com.br [Universidade Federal de Minas Gerais (UFMG), Belo Horizonte, MG (Brazil). Departamento de Engenharia Nuclear; Dias, Humberto G., E-mail: fisicamedica.hl@mariopenna.org.br [Luxemburgo Hospital, Mario Penna Institute, Belo Horizonte, MG (Brazil)

    2015-07-01

    The main goal of this work was to evaluate the spatial dose distribution into a tumor simulator inside a head phantom exposed to a 15MV 3D conformal radiation therapy in order to validate internal doses. A head and neck phantom developed by the Ionizing Radiation Research Group (NRI) was used on the experiments. Therapy Radiation planning (TPS) was performed based on those CT images, satisfying a 200 cGy prescribed dose split in three irradiation fields. The TPS assumed 97% of prescribed dose cover the prescribed treatment volume (PTV). Radiochromic films in a solid water phantom provided dose response as a function of optical density. Spatial dosimetric distribution was generated by radiochromic film samples inserted into tumor simulator and brain. The spatial dose profiles held 70 to 120% of the prescribed dose. In spite of the stratified profile, as opposed to the smooth dose profile from TPS, the tumor internal doses were within a 5% deviation from 214.4 cGy evaluated by TPS. 83.2% of the points with a gamma value of less than 1 (3%/3mm) for TPS and experimental values, respectively. At the tumor, a few dark spots in the film caused the appearance of outlier points in 13-15% of dose deviation percentage. As final conclusion, such dosimeter choice and the physical anthropomorphic and anthropometric phantom provided an efficient method for validating radiotherapy protocols. (author)

  19. Phantom dosimetry at 15 MV conformal radiation therapy

    Energy Technology Data Exchange (ETDEWEB)

    Thompson, Larissa; Campos, Tarcisio P.R., E-mail: larissathompson@hotmail.com, E-mail: tprcampos@yahoo.com.br [Universidade Federal de Minas Gerais (UFMG), Minas Gerais, MG (Brazil). Dept. de Engenharia Nuclear; Dias, Humberto G., E-mail: fisicamedica.hl@mariopenna.org.br [Instituto Mario Penna, Minas Gerais, MG (Brazil). Hospital Luxemburgo

    2013-07-01

    The main goal of this work was to evaluate the spatial dose distribution into a tumor simulator inside a head phantom exposed to a 15MV 3D conformal radiation therapy in order to validate internal doses. A head and neck phantom developed by the Ionizing Radiation Research Group (NRI) was used on the experiments. Therapy Radiation planning (TPS) was performed based on those CT images, satisfying a 200 cGy prescribed dose split in three irradiation fields. The TPS assumed 97% of prescribed dose cover the prescribed treatment volume (PTV). Radiochromic films in a solid water phantom provided dose response as a function of optical density. Spatial dosimetric distribution was generated by radiochromic film samples inserted into tumor simulator and brain. The spatial dose profiles held 70 to 120% of the prescribed dose. In spite of the stratified profile, as opposed to the smooth dose profile from TPS, the tumor internal doses were within a 5% deviation from 214.4 cGy evaluated by TPS. 83.2% of the points with a gamma value of less than 1 (3%/3mm) for TPS and experimental values, respectively. At the tumor, a few dark spots in the film caused the appearance of outlier points in 13-15% of dose deviation percentage. As final conclusion, such dosimeter choice and the physical anthropomorphic and anthropometric phantom provided an efficient method for validating radiotherapy protocols. (author)

  20. Temperature variations as a source of uncertainty in medical fiber-coupled organic plastic scintillator dosimetry

    DEFF Research Database (Denmark)

    Buranurak, Siritorn; Andersen, Claus Erik; Beierholm, Anders Ravnsborg

    2013-01-01

    Fiber-coupled organic plastic scintillators have potential applications in medical dosimetry related to, for example, brachytherapy and external beam radiotherapy with MV photons. As medical dosimetry generally strives for high accuracy, we designed a study to assess if the light yield from...

  1. Film Dosimetry of small electron fields

    International Nuclear Information System (INIS)

    Gitman, R.; Tatcher, M; Bar-Daroma, R.; Kuten, A.

    2002-01-01

    Radiotherapy patients are often treated with small electron fields produced by inserting cutouts in regular electron beam applicators. The dosimetric characteristics of such shaped beams are quite different from those of the open applicator. Although several investigations of small electron field dosimetry have been published, for appropriate treatment of patients, dosimetric measurements are required for each specific accelerator. Film dosimetry is the most common method for determining electron beam dose distribution characteristics because it is rapid and has good spatial resolution. However, precautions must be taken to ensure reliability [4]. In this preliminary report we describe the application of the film dosimetry method to generate the central axis percent depth doses (PDD) of a range of small electron fields from an accelerator installed at the Rambam Medical Center

  2. The ESTRO-EQUAL quality assurance network for photon and electron radiotherapy beams in Germany

    International Nuclear Information System (INIS)

    Ferreira, I.H.; Dutreix, A.; Richter, J.; Bridier, A.; Chavaudra, J.; Svensson, H.

    2001-01-01

    Background: In 1998 an ESTRO Quality Assurance Network for radiotherapy (EQUAL) has been set up for 25 European countries for photon and electron beams in reference and non-reference conditions. Material and Methods: Measurements are done using LiF powder (DTL937-Philitech, France) that is processed with the PCL3 automatic reader (Fimel-PTW). The participating centers irradiate the TLDs with an absorbed dose of 2 Gy according to the clinical routine. Results: Until September 2000 EQUAL has checked 135 photon beams (including the beams rechecked) from 51 radiotherapy centers in Germany out of 86 accepted centers. The results show that 2% of the beam outputs in reference conditions and 3% of the percentage depth doses are outside the tolerance level (deviation > ± 5%). 6% of the beam output variations and of the wedge transmission factors show deviations > ± 5%. The global analysis of results shows deviations > ± 5% in at least one parameter for 18 beams out of the 135 beams checked. Five rechecked beams present one ''real dosimetric'' problem in one or more parameters, corresponding to 4% of the 114 beams for which the deviations cannot be attributed to set-up errors. - The EQUAL network has checked 89 electron beams in Germany. The results show that all beam outputs checked are within the tolerance level. The standard deviation for the beam output in reference conditions is 2.0% and 2.2% for the beam output for the others field sizes. The percentage of deviations > 3% and ≤ 5% for the reference beam output is higher for electron beams than for photon beam checks. Therefore the electron beam calibration and the TPS algorithms should be improved to increase the accuracy of the patient dosimetry for radiotherapy. (orig.) [de

  3. Antibacterial activity of sulfamethoxazole transformation products (TPs): general relevance for sulfonamide TPs modified at the para position.

    Science.gov (United States)

    Majewsky, Marius; Wagner, Danny; Delay, Markus; Bräse, Stefan; Yargeau, Viviane; Horn, Harald

    2014-10-20

    Sulfonamide antibiotics undergo transformation in the aquatic environment through biodegradation, photolysis, or hydrolysis. In this study, the residual antibacterial activity of 11 transformation products (TPs) of sulfamethoxazole (SMX) was investigated with regard to their in vitro growth and luminescence inhibition on Vibrio fischeri (30 min and 24 h exposure). Two transformation products, 4-hydroxy-SMX and N(4)-hydroxy-acetyl-SMX, were synthesized in-house and confirmed by nuclear magnetic resonance and high-resolution mass spectrometry. Results of individual compound experiments showed that TPs modified at the para amino group still exhibit clear antibacterial effects, whereas TPs resulting from breakdown of the SMX structure lost this mechanism of action. 4-NO2- and 4-OH-SMX were found to inhibit growth to a clearly greater extent than the parent compound, SMX. In contrast, the N(4)-acetyl- and N(4)-hydroxy-acetyl-derivatives retain less than 10 and 5% of the effect of SMX on growth and luminescence inhibition, respectively. The effect of a mixture of para-modified TPs was observed to be additive. Considering the homologous series of sulfa drugs widely prescribed and their common mechanism of action, the potential environmental impact must consider the total amount of sulfonamide antibiotics and their derivative TPs, which might end up in a water body. Extrapolating the results obtained here for the para TPs of SMX to other sulfa drugs and determining the persistence and occurrence of these compounds in the aquatic environment is required for improved risk assessment.

  4. SU-C-201-02: Dosimetric Verification of SBRT with FFF-VMAT Using a 3-D Radiochromic/Optical-CT Dosimetry System

    Energy Technology Data Exchange (ETDEWEB)

    Na, Y; Black, P; Wuu, C [Columbia University, New York, NY (United States); Adamovics, J [Department of Chemistry and Biology, Rider University, Skillman, NJ (United States)

    2016-06-15

    Purpose: With an increasing use of small field size and high dose rate irradiation in the advances of radiotherapy techniques, such as stereotactic body radiotherapy (SBRT) and stereotactic radiosurgery (SRS), an in-depth quality assurance (QA) system is required. The purpose of this study is to investigate a high resolution optical CT-based 3D radiochromic dosimetry system for SBRT with intensity modulated radiotherapy (IMRT) and flattening filter free (FFF) volumetric modulated arc therapy (VMAT). Methods: Cylindrical PRESAGE radiochromic dosimeters of 10cm height and 11cm diameter were used to validate SBRT. Four external landmarks were placed on the surface of each dosimeter to define the isocenter of target. SBRT plans were delivered using a Varian TrueBeam™ linear accelerator (LINAC). Three validation plans, SBRT with IMRT (6MV 600MU/min), FFF-VMAT (10MV 2400MU/min), and mixed FFF-VMAT (6MV 1400MU/min, 10MV 2400MU/min), were delivered to the PRESAGE dosimeters. Each irradiated PRESAGE dosimeter was scanned using a single laser beam optical CT scanner and reconstructed with a 1mm × 1mm high spatial resolution. The comparison of measured dose distributions of irradiated PRESAGE dosimeters to those calculated by Pinnacle{sup 3} treatment planning system (TPS) were performed with a 10% dose threshold, 3% dose difference (DD), and 3mm distance-to-agreement (DTA) Gamma criteria. Results: The average pass rates for the gamma comparisons between PRESAGE and Pinnacle{sup 3} in the transverse, sagittal, coronal planes were 94.6%, 95.9%, and 96.4% for SBRT with IMRT, FFF-VMAT, and mixed FFF-VMAT plans, respectively. A good agreement of the isodose distributions of those comparisons were shown at the isodose lines 50%, 70%, 80%, 90% and 98%. Conclusion: This study demonstrates the feasibility of the high resolution optical CT-based 3D radiochromic dosimetry system for validation of SBRT with IMRT and FFF-VMAT. This dosimetry system offers higher precision QA with 3D

  5. A comparative study on patient specific absolute dosimetry using slab phantom, acrylic body phantom and goat head phantom

    Directory of Open Access Journals (Sweden)

    Om Prakash Gurjar

    2015-01-01

    Full Text Available Purpose: To compare the results of patient specific absolute dosimetry using slab phantom, acrylic body phantom and goat head phantom. Methods: Fifteen intensity modulated radiotherapy (IMRT plans already planned on treatment planning system (TPS for head-and-neck cancer patients were exported on all three kinds of phantoms viz. slab phantom, acrylic body phantom and goat head phantom, and dose was calculated using anisotropic analytic algorithm (AAA. All the gantry angles were set to zero in case of slab phantom while set to as it is in actual plan in case of other two phantoms. All the plans were delivered by linear accelerator (LA and dose for each plan was measured by 0.13 cc ion chamber. The percentage (% variations between planned and measured doses were calculated and analyzed. Results: The mean % variations between planned and measured doses of all IMRT quality assurance (QA plans were as 0.65 (Standard deviation (SD: 0.38 with confidence limit (CL 1.39, 1.16 (SD: 0.61 with CL 2.36 and 2.40 (SD: 0.86 with CL 4.09 for slab phantom, acrylic head phantom and goat head phantom respectively. Conclusion: Higher dose variations found in case of real tissue phantom compare to results in case of slab and acrylic body phantoms. The algorithm AAA does not calculate doses in heterogeneous medium as accurate as it calculates in homogeneous medium. Therefore the patient specific absolute dosimetry should be done using heterogeneous phantom mimicking density wise as well as design wise to the actual human body.  

  6. The IAEA/WHO thermoluminescent dosimetry intercomparison used for the improvement of clinical dosimetry

    International Nuclear Information System (INIS)

    Racoveanu, N.T.

    1981-01-01

    Results of thermoluminescent dosimetry collected over 5 years in the Eastern Mediterranean region of WHO were analyzed in an attempt to improve clinical dosimetry. Data for 16 radiotherapy departments showed considerable inconsistencies. It was found that the clinical dosemeters used by 3 of the departments were not working properly. The remainder of the departments had one or more dosemeters in perfect working order but the procedure for measuring machine output was inadequate or the correction factors (pressure, temperature) were wrongly applied due to lack of reliable instruments for such measurements. Problems encountered in the sending and returning of TLD dosemeters for assessment are discussed

  7. TPS/LDPE blends reinforced with lignocellulose fibers; Compositos TPS/LDPE reforcados com fibras lignocelulosicas

    Energy Technology Data Exchange (ETDEWEB)

    Lopes, G.K.; Andrade, C.T., E-mail: kloc@ima.ufrj.b [Universidade Federal do Rio de Janeiro (IMA/UFRJ), RJ (Brazil). Inst. de Macromoleculas Eloisa Mano

    2010-07-01

    Because of their abundance, availability, low abrasiveness and mechanical properties, cellulose fibers have been frequently chosen as reinforcing fillers in composites. Castor bean cake, the residue from biodiesel production, is rich in lignocellulose fibers and proteins. One of these proteins is ricin, a toxin protein. In this work, ricin was denatured by heat treatment in water at 90 deg C for 4 h. Thermoplastic starch (TPS), low density polyethylene (LDPE), maleated polyethylene (used as the compatibilizing agent), and an organophilic clay were processed in the presence of different contents of heat treated castor bean cake. Processing was carried out in a single-screw extruder, at 400 rpm, with heat zones at 130 deg C, 135 deg C, 135 deg C and 130 deg C (from feed zone to die end). The structural and mechanical properties of the resulting polymeric composites were investigated, and revealed the reinforcing effect of the partially purified cellulose fibers. (author)

  8. Woven TPS Enabling Missions Beyond Heritage Carbon Phenolic

    Science.gov (United States)

    Stackpoole, M.; Feldman, J.; Venkatapathy, E.

    2013-01-01

    WTPS is a new approach to producing TPS architectures that uses precisely engineered 3D weaving techniques to customize material characteristics needed to meet specific missions requirements for protecting space vehicles from the intense heating generated during atmospheric entry. Using WTPS, sustainable, scalable, mission-optimized TPS solutions can be achieved with relatively low life cycle costs compared with the high costs and long development schedules currently associated with material development and certification. WTPS leverages the mature state-of-the-art weaving technology that has evolved from the textile industry to design TPS materials with tailorable performance. Currently, missions anticipated encountering heat fluxes in the range of 1500 4000 Wcm2 and pressures greater than 1.5 atm are limited to using fully dense Carbon Phenolic. However, fully dense carbon phenolic is only mass efficient at higher heat fluxes greater than 4000 Wcm2), and current mission designs suffer this mass inefficiency for lack of an alternative mid-density TPS. WTPS not only bridges this mid-density TPS gap but also offers a replacement for carbon phenolic, which itself requires a significant and costly redevelopment effort to re-establish its capability for use in the high heat flux missions recently prioritized in the NRC Decadal survey, including probe missions to Venus, Saturn and Neptune. This presentation will overview the WTPS concept and present some results from initial testing completed comparing WTPS architectures to heritage carbon phenolic.

  9. Dosimetry and treatment planning of Occu-Prosta 125I seeds for intraocular lesions

    International Nuclear Information System (INIS)

    Chaudhari, Suresh; Deshpande, Sudesh; Anand, Vivek; De, Sandeep; Kannan, V.; Saxena, Sanjay; Dash, A.; Basu, Mahua; Samant, Preetam

    2008-01-01

    Intraocular malignant lesions are frequently encountered in clinical practice. Plaque brachytherapy represents an effective means of treatment for intraocular lesions. Recently Radiopharmaceutical Division, BARC, Mumbai, has indigenously fabricated reasonable-cost 125 I sources. Here we are presenting the preliminary experience of dosimetry of sources, configuration of treatment planning system (TPS) and quality assurance (QA) for eye plaque therapy with Occu-Prosta 125 I seeds, treated in our hospital, for a patient with ocular lesions. 125 I seeds were calibrated using well-type chamber. BrachyVision TPS was configured with Monte Carlo computed radial dose functions and anisotropy functions for 125 I sources. Dose calculated by TPS at different points in central axis and off axis was compared with manually calculated dose. Eye plaque was fabricated of 17 karat pure gold, locally. The seeds were arranged in an outer ring near the edge of the plaque and in concentric rings throughout the plaque. The sources were manually digitized on the TPS, and dose distribution was calculated in three dimensions. Measured activity using cross-calibrated well-type chamber was within ± 10% of the activity specified by the supplier. Difference in TPS-calculated dose and manually calculated dose was within 5%. Treatment time calculated by TPS was in concordance with published data for similar plaque arrangement. (author)

  10. Fast neutron dosimetry

    International Nuclear Information System (INIS)

    DeLuca, P.M. Jr.; Pearson, D.W.

    1991-01-01

    During 1988--1990 the magnetic resonance dosimetry project was completed, as were the 250 MeV proton shielding measurements. The first cellular experiment using human cells in vitro at the 1 GeV electron storage ring was also accomplished. More detail may be found in DOE Report number-sign DOE/EV/60417-002 and the open literature cited in the individual progress subsections. We report Kinetic Energy Released in Matter (KERMA), factor measurements in several elements of critical importance to neutron radiation therapy and radiation protection for space habitation and exploration for neutron energies below 30 MeV. The results of this effort provide the only direct measurements of the oxygen and magnesium kerma factors above 20 MeV neutron energy, and the only measurements of the iron kerma factor above 15 MeV. They provide data of immediate relevance to neutron radiotherapy and impose strict criteria for normalizing and testing nuclear models used to calculate kerma factors at higher neutron energies

  11. Computational dosimetry and risk assessment of radioinduced cancer: studies in mammary glands radiotherapy, radiopharmaceuticals and internal contamination; Dosimetria computacional e estimativa de risco de câncer radioinduzido: estudos em radioterapia de mama, radiofármacos e contaminação interna

    Energy Technology Data Exchange (ETDEWEB)

    Mendes, Bruno Melo

    2017-07-01

    The use of Ionizing radiation (IR) in medicine has increased considerably. The benefits generated by diagnostic and therapy techniques with IR are proven. Nevertheless, the risks arising from these uses should not be underestimated. Justification, a basic radiation protection, states that the benefits from exposures must outweigh detriment. The cancer induction is one of the detriment components. Thus, the study of the benefit/detriment ratio should take into account cancer incidence and mortality estimations resulting from a given diagnosis or therapy radiological technique. The risk of cancer induction depends on the absorbed doses in the irradiated organs and tissues. Thus, IR dosimetry is essential to evaluate the benefit/detriment ratio. The present work aims to perform computational dosimetric evaluations and estimations of cancer induction risk after ionizing radiation exposure. The investigated situations cover nuclear medicine, radiological contamination and radiotherapy fields. Computational dosimetry, with MCNPx Monte Carlo Code, was used as a tool to calculate the absorbed dose in the interest organs of the voxelized human models. The simulations were also used to obtain calibration factors and optimization of in vivo monitoring systems for internal contamination dosimetry. A breast radiotherapy (RT) standard protocol was simulated using the MCNPx code. The calculation of the radiation-induced cancer risk was adapted from the BEIR VII methodology for the Brazilian population. The absorbed doses used in the risk calculations were obtained through computational simulations of different exposure scenarios. During this work, two new computational phantoms, DM{sub B}RA and VW, were generated from tomographic images. Additional twelve voxelized phantoms, including the reference phantoms, RCP{sub A}M and RCP{sub A}F, and the child, baby, and fetus models were adapted to run on MCNP. Internal Dosimetry Protocols (IDP) for radiopharmaceuticals and for internal

  12. Why Radiotherapy Works. Chapter 6

    International Nuclear Information System (INIS)

    Tashiro, S.; Nishibuchi, I.; Wondergem, J.

    2017-01-01

    The history of radiotherapy began in 1895, when Röntgen discovered X rays, and in the following year, radiation was used for medical treatment. In the early days, the development of radiotherapy was based extensively on empiricism. Radiotherapists worked closely with radiation biologists in attempting to describe and understand the phenomena produced by ionizing radiation in the clinic and in biological systems. During the ensuing 120 years, radiotherapy has been improved significantly and, in addition to radiation biology, medical physics has played an important role in the design and development of equipment, quality assurance and dosimetry. Over recent decades, advances have been made in the field of molecular biology. Currently available techniques enable us to elucidate the molecular mechanisms of cellular response to ionizing irradiation, and it is anticipated that the role and contributions of radiation biology in radiotherapy will remain relevant. This chapter describes the clinically important biological points, including knowledge from current molecular biology.

  13. Experiences with alanine dosimetry in afterloading brachytherapy

    International Nuclear Information System (INIS)

    Eberhardt, H.-J.; Gohs, U.

    1996-01-01

    At the present, the most commonly used dosimetry for radiotherapy applications are ionisation chambers and thermoluminescent dosimeters (TLD). However, there are some undesirable characteristics of these dosimetry systems, such as large detection volume (ionisation chamber) as well as fading of the radiation induced signal with time and destructive readout (TLG). The present study is an investigation into the use of the alanine/ESR dosimetry in fractionated afterloading brachytherapy during the whole radiotherapy course. There are some qualities which make alanine dosimetry attractive. These are the linear energy response, low fading under standard conditions, and the nondestructive readout. Thus the alanine dosimetry makes possible cumulative dose measurements during the radiotherapy course and an archival storage. By ionizing radiation (gamma, e, n, p, charged particles) free radicals (unpaired electrons) are produced in the amino acid alanine. The continuous wave electron spin resonance (ESR) spectroscopy is used to determine the number of free radicals, which is proportional to the absorbed dose and the alanine content of the dosimeter. The ESR measurements were made at room temperature using a Bruker EPR analyzer EMS-104. The dosimeters used in the test are alanine pellets (23.72 mg weight, 4.9 mm diameter, 1 mm height) as well as flexible alanine film dosimeters (thickness about 500 μm). The dosimeters consist of a blend of L-alpha-alanine and a binder. The alanine content of the pellets and the film dosimeters is about 88 % and 50 % by weight, respectively. The dosimeters for the calculation of the dose-effect-relationship were irradiated at the Physical-Technical Bundesanstalt in Braunschweig by a standard 60Co source. The maximum deviation from the calculated linear function is about 0.12 Gy in the dose range up to 80 Gy. The goal of medical applications was the superficial dose measurement in afterloading brachytherapy during the radiotherapy course in

  14. Personnel neutron dosimetry

    International Nuclear Information System (INIS)

    Hankins, D.

    1982-04-01

    This edited transcript of a presentation on personnel neutron discusses the accuracy of present dosimetry practices, requirements, calibration, dosemeter types, quality factors, operational problems, and dosimetry for a criticality accident. 32 figs

  15. Physical fundamentals of the application of heavy charged particles in radiotherapy

    International Nuclear Information System (INIS)

    Bueche, G.

    1977-01-01

    In the chapter 'Medical Applications' A 'Radiotherapy' of the study, the following subjects are treated in detail by various authors: Physical fundamentals of the application of heavy charged particles in radiotherapy-radiation-biological fundamentals; clinical aspects of radiotherapy with protons and negative pions; patients and clinical dosimetry. (MG) [de

  16. Dosimetry for radiation processing

    DEFF Research Database (Denmark)

    Miller, Arne

    1986-01-01

    During the past few years significant advances have taken place in the different areas of dosimetry for radiation processing, mainly stimulated by the increased interest in radiation for food preservation, plastic processing and sterilization of medical products. Reference services both...... and sterilization dosimetry, optichromic dosimeters in the shape of small tubes for food processing, and ESR spectroscopy of alanine for reference dosimetry. In this paper the special features of radiation processing dosimetry are discussed, several commonly used dosimeters are reviewed, and factors leading...

  17. Space dosimetry

    International Nuclear Information System (INIS)

    Doke, Tadayoshi

    1988-01-01

    Japan will take part in the LML-1 (International Microgravity Laboratory 1) program that is scheduled to be carried out with space shuttles to be launched in 1991. The program will be followed by the LS-J (Space Laboratory-Japan) and IML-2 programs. A reliable dosimetry system is currently required to be established to evaluate the radiations in space. The present article reviews major features of different types of space radiations and requirements of dosimeters for these radiations. The radiations in the space environment consist of: 1) electrons and protons that have been trapped by the terrestrial magnetism, 2) corpuscular, gamma-and X-rays released from the sun, and 3) galactic cosmic rays (corpuscular, gamma-and X-rays). The effects of the trapped radiations will be low if a spacecraft can get through the zone of such radiations in a short period of time. The effects of galactic cosmic rays are much smaller than those of the trapped radiations. A solar flare can give significant contributions to the total radiations received by a spacecraft. An extremely large flare can release a fatal amount of radiations to the crew of a spacecraft. Prediction of such a large flare is of great important for a long trip through the space. Significant improvements should be made on existing dosimeters. (Nogami, K.)

  18. Implementation of MRI gel dosimetry in radiation therapy

    International Nuclear Information System (INIS)

    Baeck, S.Aa.J.

    1998-12-01

    Gel dosimetry was used together with magnetic resonance imaging (MRI) to measure three-dimensional absorbed dose distributions in radiation therapy. Two different dosimeters were studied: ferrous- and monomer gel, based on the principles of radiation-induced oxidation and polymerisation, respectively. Single clinical electron and photon beams were evaluated and gel dose distributions were mainly within 2% of conventional detector results. The ferrous-gel was also used for clinical proton beams. A decrease in signal per absorbed dose was found close to the end of the range of the protons (15-20%). This effect was explained as a linear energy transfer dependence, further supported with Monte Carlo simulations. A method for analysing and comparing data from treatment planning system (TPS) and gel measurements was developed. The method enables a new pixel by pixel evaluation, isodose comparison and dose volume histogram verification. Two standard clinical radiation therapy procedures were examined using the developed TPS verification method. The treatment regimes included several beams of different radiation qualities. The TPS calculated data were in very good agreement with the dose distribution measured by the ferrous-gel. However, in a beam abutment region, larger dose difference was found. Beam adjustment errors and a minor TPS underestimation of the lateral scatter contribution outside the primary electron beam may explain the discrepancy. The overall uncertainty in the ferrous-gel dose determination was considerably reduced using an optimised MRI acquisition protocol and a new MRI scanner. The relative dose uncertainty was found to be better than 3.3% for all dose levels (95% confidence level). Using the method developed for comparing measured gel data with calculated treatment plans, the gel dosimetry method was proven to be a useful tool for radiation treatment planning verification

  19. Implementation of MRI gel dosimetry in radiation therapy

    Energy Technology Data Exchange (ETDEWEB)

    Baeck, S.Aa.J

    1998-12-01

    Gel dosimetry was used together with magnetic resonance imaging (MRI) to measure three-dimensional absorbed dose distributions in radiation therapy. Two different dosimeters were studied: ferrous- and monomer gel, based on the principles of radiation-induced oxidation and polymerisation, respectively. Single clinical electron and photon beams were evaluated and gel dose distributions were mainly within 2% of conventional detector results. The ferrous-gel was also used for clinical proton beams. A decrease in signal per absorbed dose was found close to the end of the range of the protons (15-20%). This effect was explained as a linear energy transfer dependence, further supported with Monte Carlo simulations. A method for analysing and comparing data from treatment planning system (TPS) and gel measurements was developed. The method enables a new pixel by pixel evaluation, isodose comparison and dose volume histogram verification. Two standard clinical radiation therapy procedures were examined using the developed TPS verification method. The treatment regimes included several beams of different radiation qualities. The TPS calculated data were in very good agreement with the dose distribution measured by the ferrous-gel. However, in a beam abutment region, larger dose difference was found. Beam adjustment errors and a minor TPS underestimation of the lateral scatter contribution outside the primary electron beam may explain the discrepancy. The overall uncertainty in the ferrous-gel dose determination was considerably reduced using an optimised MRI acquisition protocol and a new MRI scanner. The relative dose uncertainty was found to be better than 3.3% for all dose levels (95% confidence level). Using the method developed for comparing measured gel data with calculated treatment plans, the gel dosimetry method was proven to be a useful tool for radiation treatment planning verification 103 refs, 20 figs, 6 tabs

  20. QA programme in external radiotherapy in Romania - status and perspective

    International Nuclear Information System (INIS)

    Dumitrescu, A.; Milu, C.

    2008-01-01

    Full text: Recognizing the importance of quality assurance in radiotherapy and the need to make access to radiation standards traceable to the international measurement system for every radiotherapy center, the Romanian national secondary standard dosimetry laboratory (SSDL) has started in 1999 - together with IAEA - a national quality audit programme in all the centers for external radiotherapy from Romania. At present, there are 17 radiotherapy centers in Romania, and a total of 19 teletherapy units and 4 LINCs. The programme has 3 phases: the first phase was to organize a survey in all radiotherapy centers, to collect general information on their radio therapists, medical physicists, type of equipment, dosimeters, etc. Following the survey, a quality assurance network was set up, and on-site dosimetry reviews were arranged according to a suitable timetable. The second phase consisted in performing the reference dosimetry and the calibration of the equipment. Then, a quality audit system based on mailed TLDs has been applied to all radiation beams produced by cobalt-60 therapy units and medical accelerators, in order to identify discrepancies in dosimetry larger than ± 3%. At the same time, the beam calibration performed by the SSDLs was verified. The results of the first survey were analyzed, and corrective actions were taken. A second survey was then organized, based on the mailed TLDs. This paper presents in detail the entire QA programme, its results, and the actions that are to be taken in order to improve the accuracy and consistency of the dosimetry in clinical radiotherapy in Romania. (author)

  1. Chemical dosimetry techniques for various applications under different geometries

    CERN Document Server

    Gupta, B L; Narayan, G R; Nilekani, S R

    2000-01-01

    This paper gives the results of dosimetry for various applications under different geometrical arrangements. These applications include: gamma chambers, blood irradiators, radiotherapy using both sup 6 sup 0 Co and accelerators, animal irradiations with different types of radiation sources, fluid irradiators for sludge and rubber latex and industrial electron irradiators. The dosimeters used were Fricke, FBX and alanine/glutamine (spectrophotometric readout).

  2. Dosimetry and microdosimetry using Let spectrometer based on the track-etch detector: radiotherapy Bremsstrahlung beam, onboard aircraft radiation field; Dosimetrie et micro-dosimetrie au moyen d'un spectrometre a transfert lineique d'energie base sur des detecteurs solides de traces: mesure dans un faisceau de rayonnement X de radiotherapie et du champ de rayonnement a bord d'avion

    Energy Technology Data Exchange (ETDEWEB)

    Jadrneckova, I.; Spurny, F. [Nuclear Physics Institute AS CR, Dept. of Radiation Dosimetry, Prague (Czech Republic); Jadrneckova, I. [Czech Technical Univ., Dept. of Dosimetry and Application of Ionizing Radiation, Prague (Czech Republic)

    2006-10-15

    The spectrometer of linear energy transfer (LET) based on the chemically etched poly-allyl-diglycol-carbonate (PADC) track-etch detector was developed several years ago in our institute. LET spectra are estimated through track parameters determination carried out by an automatic optical image analyzer LUCIA G. This LET spectrometer enables determining LET of particles approximately from 10 to 700 keV/{mu}m. From the LET spectra, dose characteristics can be calculated. This contribution presents the use of this spectrometer in some applications - studies in 18 MV radiotherapy Bremsstrahlung beam and investigation onboard a commercial aircraft during more than 6 months long exposure. The LET spectra obtained in both experiments represent mainly the contribution of secondary or tertiary particles created through the nuclear reactions of photons (Bremsstrahlung beam) or neutrons and neutron-like reacting particles (onboard aircraft) in the detector itself or in the surroundings material. The dose due to the photo-particles represents about 3 x 10{sup -4} of the photon dose; for the dose equivalent this value is about 2 x 10{sup -3} Sv/Gy. Regarding the onboard aircraft exposure, the results obtained using LET spectrometer were compared with those achieved with other methods and a reasonable agreement were stated. (authors)

  3. KOMPARASI MODEL PEMBELAJARAN TPS DAN SFE TERHADAP KEMAMPUAN PEMAHAMAN KONSEP

    Directory of Open Access Journals (Sweden)

    Febri Susanto

    2014-03-01

    Full Text Available Penelitian ini bertujuan untuk mengetahui apakah pembelajaran model Think Pair Share (TPS dan model Student Facilitator and Explaining (SFE pada siswa kelas X materi jarak pada bangun ruang dapat mencapai ketuntasan belajar dan untuk mengetahui manakah yang lebih efektif antara pembelajaran model Think Pair Share (TPS dan model Student Facilitator and Explaining (SFE. Populasi dalam penelitian ini adalah siswa kelas X SMA N 1 Kota Tegal tahun pelajaran 2012/2013 yang berada dalam sembilan kelas. Sembilan kelas tersebut kemudian dipilih dua kelas secara acak untuk dijadikan sampel dalam penelitian ini yaitu kelas X 2 sebagai kelas eksperimen 1 dan kelas X 1 sebagai kelas eksperimen 2. Uji ketuntasan belajar memberikan hasil yaitu siswa kelas eksperimen 1 dan 2 telah mencapai ketuntasan belajar. Uji kesamaan dua proporsi memberikan hasil yakni proporsi ketuntasan belajar pada aspek pemahaman konsep siswa kelas eksperimen 1 sama baiknya dibanding proporsi ketuntasan belajar pada aspek pemahaman konsep siswa kelas eksperimen 2. Hasil Penelitian menunjukkan pembelajaran model TPS dan SFE pada materi jarak pada bangun ruang telah mencapai ketuntasan belajar dan model pembelajaran TPS sama efektifnya dengan pembelajaran model SFE.

  4. Online fibre optic OSL in vivo dosimetry for quality assurance of external beam radiation therapy treatments: The ANR-TECSAN Codofer Project; Dosimetrie in vivo par OSL, en ligne par fibre optique, pour l'assurance qualite des traitements par radiotherapie externe: le projet ANR-TECSAN Codofer

    Energy Technology Data Exchange (ETDEWEB)

    Magne, S.; Ferdinand, P. [CEA Saclay, Laboratoire de mesures optiques, CEA LIST, 91191 Gif-sur-Yvette (France); De Carlan, L. [CEA Saclay, Laboratoire national Henri-Becquerel, CEA LIST, 91191 Gif-sur-Yvette (France); Bridier, A.; Isambert, A. [Service de physique, institut Gustave-Roussy, 39, rue Camille-Desmoulins, 94805 Villejuif (France); Hugon, R. [CEA Saclay, Departement capteur, signal et informations, CEA LIST, 91191 Gif-sur-Yvette (France); Guillon, J. [Societe Fimel, 18, rue Marie-et-Pierre-Curie, 92260 Fontenay-aux-Roses (France)

    2010-05-15

    The Codofer Project (2007-2009), led under the ANR-TECSAN Call, was coordinated by CEA LIST, in partnership with IGR and the Fimel company. The aim of the project was to design and test both metrologically and in clinical conditions OSL optical fiber sensors dedicated to in vivo dosimetry during external beam radiation therapy treatment with high-energy electrons. This study, combined with the results of clinical tests obtained within the European Project Maestro, has demonstrated the advantages of OSL/FO dosimetry for providing quality assurance of treatments. However, the French market for dosimetry has greatly changed as a result of the rules decreed by the French government in 2007. The OSL/FO product is now targeted for other treatment modalities lacking suitable dosimeters (ANR-INTRADOSE Project [2009-2011]). (authors)

  5. High-temperature behavior of advanced spacecraft TPS

    Science.gov (United States)

    Pallix, Joan

    1994-05-01

    The objective of this work has been to develop more efficient, lighter weight, and higher temperature thermal protection systems (TPS) for future reentry space vehicles. The research carried out during this funding period involved the design, analysis, testing, fabrication, and characterization of thermal protection materials to be used on future hypersonic vehicles. This work is important for the prediction of material performance at high temperature and aids in the design of thermal protection systems for a number of programs including programs such as the National Aerospace Plane (NASP), Pegasus and Pegasus/SWERVE, the Comet Rendezvous and Flyby Vehicle (CRAF), and the Mars mission entry vehicles. Research has been performed in two main areas including development and testing of thermal protection systems (TPS) and computational research. A variety of TPS materials and coatings have been developed during this funding period. Ceramic coatings were developed for flexible insulations as well as for low density ceramic insulators. Chemical vapor deposition processes were established for the fabrication of ceramic matrix composites. Experimental testing and characterization of these materials has been carried out in the NASA Ames Research Center Thermophysics Facilities and in the Ames time-of-flight mass spectrometer facility. By means of computation, we have been better able to understand the flow structure and properties of the TPS components and to estimate the aerothermal heating, stress, ablation rate, thermal response, and shape change on the surfaces of TPS. In addition, work for the computational surface thermochemistry project has included modification of existing computer codes and creating new codes to model material response and shape change on atmospheric entry vehicles in a variety of environments (e.g., earth and Mars atmospheres).

  6. The physics of small megavoltage photon beam dosimetry.

    Science.gov (United States)

    Andreo, Pedro

    2017-11-27

    The increased interest during recent years in the use of small megavoltage photon beams in advanced radiotherapy techniques has led to the development of dosimetry recommendations by different national and international organizations. Their requirement of data suitable for the different clinical options available, regarding treatment units and dosimetry equipment, has generated a considerable amount of research by the scientific community during the last decade. The multiple publications in the field have led not only to the availability of new invaluable data, but have also contributed substantially to an improved understanding of the physics of their dosimetry. This work provides an overview of the most important aspects that govern the physics of small megavoltage photon beam dosimetry. Copyright © 2017 Elsevier B.V. All rights reserved.

  7. Audits for advanced treatment dosimetry

    Science.gov (United States)

    Ibbott, G. S.; Thwaites, D. I.

    2015-01-01

    Radiation therapy has advanced rapidly over the last few decades, progressing from 3D conformal treatment to image-guided intensity modulated therapy of several different flavors, both 3D and 4D and to adaptive radiotherapy. The use of intensity modulation has increased the complexity of quality assurance and essentially eliminated the physicist's ability to judge the validity of a treatment plan, even approximately, on the basis of appearance and experience. Instead, complex QA devices and procedures are required at the institutional level. Similarly, the assessment of treatment quality through remote and on-site audits also requires greater sophistication. The introduction of 3D and 4D dosimetry into external audit systems must follow, to enable quality assurance systems to perform meaningful and thorough audits.

  8. 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

  9. Application of numerical analysis methods to thermoluminescence dosimetry; Aplicacion de metodos de analisis numerico a la dosimetria por termoluminiscencia

    Energy Technology Data Exchange (ETDEWEB)

    Gomez Ros, J. M.; Delgado, A.

    1989-07-01

    This report presents the application of numerical methods to thermoluminescence dosimetry (TLD), showing the advantages obtained over conventional evaluation systems. Different configurations of the analysis method are presented to operate in specific dosimetric applications of TLD, such as environmental monitoring and mailed dosimetry systems for quality assurance in radiotherapy facilities. (Author) 10 refs.

  10. Thermal, mechanical and morphological behavior of starch thermoplastic (TPS) and polycaprolactone (PCL)

    International Nuclear Information System (INIS)

    Campos, Adriana de; Marconcini, Jose M.; Mattoso, Luiz H.C.

    2011-01-01

    Thermal, mechanical and morphological properties of thermoplastic starch (TPS) and polycaprolactone (PCL) blend obtained by extrusion was studied. The results showed that TPS/PCL blends are immiscible, however it is suggested some interaction in the interphase between TPS and PCL as observed by crystallinity decrease of the blend. The PCL addition in the TPS improves the properties and decreases the cost of the blend. (author)

  11. Cellular dosimetry

    International Nuclear Information System (INIS)

    Humm, J.L.; Chin, L.M.

    1989-01-01

    Radiation dose is a useful predictive parameter for describing radiation toxicity in conventional radiotherapy. Traditionally, in vitro radiation biology dose-effect relations are expressed in the form of cell survival curves, a semilog plot of cell survival versus dose. However, the characteristic linear or linear quadratic survival curve shape, for high- and low-LET radiations respectively, is only strictly valid when the radiation dose is uniform across the entire target population. With an external beam of 60 Co gamma rays or x-rays, a uniform field may be readily achievable. When radionuclides are incorporated into a cell milieu, several new problems emerge which can result in a departure from uniformity in energy deposition throughout a cell population. This nonuniformity can have very important consequences for the shape of the survival curve. Cases in which perturbations of source uniformity may arise include: 1. Elemental sources may equilibrate in the cell medium with partition coefficients between the extracellular, cytosol, and nuclear compartments. The effect of preferential cell internalization or binding to cell membrane of some radionuclides can increase or decrease the slope of the survival curve. 2. Radionuclides bound to antibodies, hormones, metabolite precursors, etc., may result in a source localization pattern characteristic of the carrier agent, i.e., the sources may bind to cell surface receptors or antigens, be internalized, bind to secreted antigen concentrated around a fraction of the cell population, or become directly incorporated into the cell DNA. We propose to relate the distribution of energy deposition in cell nuclei to biological correlates of cellular inactivation. The probability of each cell's survival is weighted by its individual radiation burden, and the summation of these probabilities for the cell population can be used to predict the number or fraction of cell survivors

  12. Advances in radiation therapy dosimetry

    Directory of Open Access Journals (Sweden)

    Paliwal Bhudatt

    2009-01-01

    Full Text Available During the last decade, there has been an explosion of new radiation therapy planning and delivery tools. We went through a rapid transition from conventional three-dimensional (3D conformal radiation therapy to intensity-modulated radiation therapy (IMRT treatments, and additional new techniques for motion-adaptive radiation therapy are being introduced. These advances push the frontiers in our effort to provide better patient care; and with the addition of IMRT, temporal dimensions are major challenges for the radiotherapy patient dosimetry and delivery verification. Advanced techniques are less tolerant to poor implementation than are standard techniques. Mis-administrations are more difficult to detect and can possibly lead to poor outcomes for some patients. Instead of presenting a manual on quality assurance for radiation therapy, this manuscript provides an overview of dosimetry verification tools and a focused discussion on breath holding, respiratory gating and the applications of four-dimensional computed tomography in motion management. Some of the major challenges in the above areas are discussed.

  13. Clinical radionuclide therapy dosimetry: the quest for the ''Holy Gray''

    International Nuclear Information System (INIS)

    Brans, B.; Bodei, L.; Giammarile, F.; Linden, O.; Tennvall, J.; Luster, M.; Oyen, W.J.G.

    2007-01-01

    Radionuclide therapy has distinct similarities to, but also profound differences from external radiotherapy. This review discusses techniques and results of previously developed dosimetry methods in thyroid carcinoma, neuro-endocrine tumours, solid tumours and lymphoma. In each case, emphasis is placed on the level of evidence and practical applicability. Although dosimetry has been of enormous value in the preclinical phase of radiopharmaceutical development, its clinical use to optimise administered activity on an individual patient basis has been less evident. In phase I and II trials, dosimetry may be considered an inherent part of therapy to establish the maximum tolerated dose and dose-response relationship. To prove that dosimetry-based radionuclide therapy is of additional benefit over fixed dosing or dosing per kilogram body weight, prospective randomised phase III trials with appropriate end points have to be undertaken. Data in the literature which underscore the potential of dosimetry to avoid under- and overdosing and to standardise radionuclide therapy methods internationally are very scarce. In each section, particular developments and insights into these therapies are related to opportunities for dosimetry. The recent developments in PET and PET/CT imaging, including micro-devices for animal research, and molecular medicine provide major challenges for innovative therapy and dosimetry techniques. Furthermore, the increasing scientific interest in the radiobiological features specific to radionuclide therapy will advance our ability to administer this treatment modality optimally. (orig.)

  14. Quality assurance in radiotherapy of mammary cancer

    CERN Document Server

    Mangold, C A

    2000-01-01

    characteristics and correction factors necessary for the clinical application are investigated. For the brachytherapy treatment the dose distributions calculated with the TPS are in good agreement with both TLD and radiochromic film measurements (average deviations of point doses < +- 6 %). However, close to the interface tissue-air the dose is overestimated by the TPS since it neglects the finite size of a breast and hence the associated lack of backscatter (average deviations of point doses up to -13 %). The average deviation for the in vivo measurements performed on the body surface is -9.5 (+-5.3) %. Doses delivered by external radiotherapy are significantly overestimated by the TPS in the dose points located close to the surface (up to -16 %). The deviations are due to the insufficient ability of the TPS to account for the absence of tissue in the beam. In the wedged fields negative deviations are also observed for inner dose points (up to -8 %). These disagreements are either due to a wrong determina...

  15. TLD Quality Assurance (QA) network in radiotherapy and radiology in the Czech Republic

    International Nuclear Information System (INIS)

    Kroutilikova, D.; Novak, N.; Novotny, J.

    2002-01-01

    Full text: The Czech TLD QA network was established in 1997, as a part of the External Auditing Group (EAG) originated in 1995, in order to perform an independent quality audit in external beam therapy for two purposes: a) to unify the dose within radiotherapy departments, b) to impact state supervision. On basis of a good experience with this network in radiotherapy, new methods were developed to expand the network also to radiology in order to simplify the operation of state supervision. The TLD QA network in dental radiology has been brought into practice in 2001. Both the TLD audits performed in radiotherapy and radiology are realized via mailed dosimetry. In radiotherapy, two modes of the audit are used. Basic mode of TLD audit covers measurements under reference conditions, specifically beam calibration checks for all clinically used photon and electron beams. According to Czech regulations every beam must be checked in this way at least once during two years' period. Advanced mode consists of measurements under both reference and non- reference conditions using Leuven multi-purpose phantom for photon beams. It enables to check a substantial part of the treatment planning process inclusive of final dose realization of the planned radiotherapy. The radiotherapy centers are instructed to deliver absorbed dose of 2 Gy to the TLDs on central beam axis based on calculated treatment time or monitor units by their treatment planning system for a particular treatment set-up. In this way the TLD measured doses are compared with the calculated ones. Deviations of ±3% are considered acceptable for both basic and advanced modes of the audit, deviations up to ±6% are still tolerable, but new audit is repeated as soon as possible to solve the dosimetry problem. Deviations above ±6% leads immediately to investigation by EAG. There are 34 centers in the Czech Republic, which provide external beam radiotherapy. Since they must undergo the basic TLD audit regularly every

  16. 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

  17. 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 .

  18. Conformal Ablative Thermal Protection Systems (CA-TPS) for Venus and Saturn Backshells

    Science.gov (United States)

    Beck, R.; Gasch, M.; Stackpoole, M.; Wilder, M.; Boghozian, T.; Chavez-Garcia, J.; Prabhu, Dinesh; Kazemba, Cole D.; Venkatapathy, E.

    2016-01-01

    This poster provides an overview of the work performed to date on the Conformal Ablative TPS (CA-TPS) element of the TPSM project out of GCDP. Under this element, NASA is developing improved ablative TPS materials based on flexible felt for reinforcement rather than rigid reinforcements. By replacing the reinforcements with felt, the resulting materials have much higher strain-to-failure and are much lower in thermal conductivity than their rigid counterparts. These characteristics should allow for larger tile sizes, direct bonding to aeroshells and even lower weight TPS. The conformal phenolic impregnated carbon felt (C-PICA) is a candidate for backshell TPS for both Venus and Saturn entry vehicles.

  19. HASIL BELAJAR DAN PEMBELAJARAN KOOPERATIF TIPE THINK PAIR SHARE (TPS

    Directory of Open Access Journals (Sweden)

    Loli Jasdilla

    2017-03-01

    Full Text Available The objectives of this research is to improve social science outcomes by using Think Pair Share (TPS for the fourth grade in elementary school. This research is classroom action research. The procedure of this research conducted planning, acting, observation, and reflection. Subject of this research was 22 students for the fourth grade in SD 20 Kalumbuk, Padang. Techniques of collecting data were using test and observation. Data analyzed by using thematic analysis. Data validated by using triangulation, member checking, and reflecivity. The students’ learning outcomes improved from 76,75% into 89,67% (very good. The result of this research shows that cooperative model of Think Pair Share (TPS type can improve social science outcomes for the fourth grade students of elementary school.

  20. Film dosimetry for IMRT: sensitivity corrections

    International Nuclear Information System (INIS)

    Suchowerska, N.; Hoban, P.; Davison, A.; Metcalfe, P.

    2000-01-01

    Full text: The trend towards conformal, dynamic and intensity modulated radiotherapy treatments has furthered the need for true integrating dosimetry. In traditional radiotherapy, film dosimetry is commonly used. The accuracy and reproducibility of film optical density as an indicator of dose, has been associated with several variables. These include the effects of film specific sensitivity, direction of exposure, chemical processing and film scanner sensitivity. In this study, a procedure is developed to account for these variables, with a particular view to film being used as a dosimeter for conformal treatments. An effective sensitometric curve was established by exposing part of a single sheet of film to known doses. All films were processed together and scanned using a DuoscanT1200 transmission scanner, resulting in 12 bit image files. The images were analysed using Osiris software and the results fitted to the modified Williamson equation: P P s (l - 10 αD ) This yields values of α [film sensitivity], and P s [saturation pixel value], allowing individual dosimetry films to be normalised to this sensitometric calibration curve. For validation, a piece of Kodak X Omat-V film was sealed in a head phantom and exposed to a total of 51 IMRT fields, delivered from 6 gantry angles. The rest of the sheet of film was resealed and exposed to four known doses, providing sensitometric data, specific to this exposure. All films were then processed, scanned and analysed as described above. Observed variations in serial films exposed to 50cGy is in the order of 9% [mean 25.0,standard deviation = 3.2]. The automatic gain of the scanner system typically contributed 4% variation and needs to be carefully monitored. Results indicate that by using the sensitometric data from each exposure, the collective errors can be minimised. The IMRT exposure results confirm that the above process is viable for use in dosimetry for conformal radiation therapy. Copyright (2000) Australasian

  1. Radiotherapy and brachytherapy

    International Nuclear Information System (INIS)

    2007-02-01

    This presentation first defines the radiotherapy and brachytherapy techniques, indicates the used ionizing radiations (electromagnetic and particles), describes the mechanisms and processes of action of ionizing radiations: they can be physical by photon-matter interactions (Compton effect and photoelectric effect) or due to electron-matter interactions (excitation, ionization), physical-chemical by direct or indirect action (DNA damage), cellular (mitotic or apoptotic death), tissue (sane and tumorous tissues and differential effect). It discusses the biological efficiency of these treatments which depends on different parameters: intrinsic radio-sensitivity, time (session fractioning and organisation in time), oxygen, radiation quality, cellular cycle, dose rate, temperature. It presents the different types of radiotherapy: external radiotherapy (general sequence, delineation, dosimetry, protection of critical organs, treatment session, quality control, monitoring consultation) and briefly presents some specific techniques (total body irradiation, total cutaneous electron therapy, pre-operation radiotherapy, radio-surgery, hadron-therapy). It proposes an overview of the main indications for this treatment: brain tumours, upper aero digestive tract tumours, bronchial tumours, oesophagus, stomach and pancreas tumours, breast tumours, cervix cancer, rectum tumour, and so on, and indicates the possible associated treatments. The next part addresses brachytherapy. It presents the principles and comments the differences with radiotherapy. It indicates the used radio-elements (Caesium 137, Iridium 192, Iodine 125), describes the implementation techniques (plastic tubes, use of iodine 125, intracavitary and endo-luminal radiation therapy). It proposes an overview of the different treated tumours (skin, breast, prostates, bronchial, oesophagus, ENT) and indicates possible early and late secondary effects for different organs

  2. Thermal Testing of Woven TPS Materials in Extreme Entry Environments

    Science.gov (United States)

    Gonzales, G.; Stackpoole, M.

    2014-01-01

    NASAs future robotic missions to Venus and outer planets, namely, Saturn, Uranus, Neptune, result in extremely high entry conditions that exceed the capabilities of current mid density ablators (PICA or Avcoat). Therefore mission planners assume the use of a fully dense carbon phenolic heatshield similar to what was flown on Pioneer Venus and Galileo. Carbon phenolic (CP) is a robust TPS however its high density and thermal conductivity constrain mission planners to steep entries, high heat fluxes, high pressures and short entry durations, in order for CP to be feasible from a mass perspective. In 2012 the Game Changing Development Program in NASAs Space Technology Mission Directorate funded NASA ARC to investigate the feasibility of a Woven Thermal Protection System to meet the needs of NASAs most challenging entry missions. The high entry conditions pose certification challenges in existing ground based test facilities. Recent updates to NASAs IHF and AEDCs H3 high temperature arcjet test facilities enable higher heatflux (2000 Wcm2) and high pressure (5 atm) testing of TPS. Some recent thermal tests of woven TPS will be discussed in this paper. These upgrades have provided a way to test higher entry conditions of potential outer planet and Venus missions and provided a baseline against carbon phenolic material. The results of these tests have given preliminary insight to sample configuration and physical recession profile characteristics.

  3. Dosimetry of radiolabeled monoclonal antibodies used for therapy

    International Nuclear Information System (INIS)

    Myers, M.J.; Hooker, G.R.; Epenetos, A.A.

    1986-01-01

    The present state of radiotherapy using labeled antibodies is reviewed. From the point of view of dosimetry, antibody therapy does not seem to have reached a stable and practicable enough state to provide an input to any but rather tentative dosimetry models. These, therefore, should not be taken too far until the problems of antibody targeting have been more fully developed. Some of the instrumental techniques for acquiring dosimetric data under clinical conditions are discussed as are some of the techniques of therapy in use today. 8 references, 3 figures

  4. Clinical application of in vivo dosimetry for external telecobalt machine

    International Nuclear Information System (INIS)

    Mohammed, H. H. M.

    2011-01-01

    In external beam radiotherapy quality assurance is carried out on the individual components of treatment chain. The patient simulating device, planning system and treatment machine are tested regularly according to set protocols developed by national and international organizations. Even thought these individual systems are not tested for errors which can be made in the transfer between the systems. The best quality assurance for the treatment planning chain. In vivo dosimetry is used as a quality assurance tool for verifying dosimetry as either the entrance or exit surface of the patient undergoing external beam radiotherapy. It is a proven reliable method of checking overall treatment accuracy, allowing verification of dosimetry and dose calculation as well as patient treatment setup. Accurate in vivo dosimetry is carried out if diodes and thermoluminescence dosimeters (TLDs). the main detector types in use for in vivo dosimetry, are carefully calibrated and the factors influencing their sensitivity are taken into account. The aim of this study was to verify the response of TLDs type (LiF: Mg, Cu, p) use in radiotherapy, to establish calibration procedure for TLDs and to evaluate entrance dose obtained by the treatment planning system with measured dose using thermoluminescence detectors. Calibration of TLDs was done using Cobalt-60 teletherapy machine, linearity and calibration factors were determined. Measurements were performed in random phantom for breast irradiation (for the breast irradiation ( For the breast irradiation technique considered, wedge field was used). All TLDs were processed and analyzed at RICK. In vivo dosimetry represents a technique that has been widely employed to evaluate the dose to the patient mainly in radiotherapy. Thermoluminescent dosimeters are considered the gold stander for in vivo dosimetry and do not require cables for measurements which makes them ideal for mail based studies and have no dose rate or temperature dependence

  5. Pilot postal audits in radiotherapy for 60Co in non-reference conditions in Cuba: practical consideration and preliminary results

    International Nuclear Information System (INIS)

    Gutierrez Lores, S.; Walwyn Salas, G.; Alonso Villanueva, G.

    2008-01-01

    Discusses the practical consideration and preliminary results of the Cuban's SSDL in Pilot Postal Audit in Radiotherapy for Co-60 in non-reference conditions under IAEA Coordinated Research Project E2.40.12. A strategy for national TLD audit programmes has been developed by the international Atomic Energy Agency (IAEA). It involves progression through three sequential dosimetry audit steps. The first step audits are for the beam output in reference conditions for photon beams. The second step audits are for the dose in reference and non-reference conditions on the beam axis for photon beams. The third step audits involve measurements of the dose in reference, and non-reference conditions off-axis for open and wedged symmetric and symmetric fields for photon beams. Under coordinated research project E2.40.12 were characterized 100 micro rods. All of these rods were identified individually with a consecutive number made over one of its sides, using a fine tip of graphite. The method used to determinate the individual sensibility of the TL detectors was: irradiating a group of them, with the same history of irradiation and readout. The TLD signal was read using HARSHAW 2000C/B reader. Based on the IAEA standard TLD holder for photon beams, a TLD holder was developed with horizontal arm to enable measurements 5 cm off the central axis. Successful results in two external trial carried out using the IAEA TLD service in the years 2003 - 2004 were obtained. Five 5 facilities were considered to be included in the Pilot Audit Audits in Radiotherapy for Co-60 in non reference conditions (on-axis) in the year 2003, according to recommendation of External Audit Group (EAG). For the year 2004 were considered only 3 facilities in the Pilot Audit Audits in Radiotherapy for Co-60 in non reference conditions (off-axis). Extend the postal dose audits to the rest of the institutions around the country. The participation in these audits promotes a major understanding of the physicists

  6. 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

  7. Personal dosimetry in Kazakhstan

    International Nuclear Information System (INIS)

    Khvoshnyanskaya, I.R.; Vdovichenko, V.G.; Lozbin, A.Yu.

    2003-01-01

    KATEP-AE Radiation Laboratory is the first organization in Kazakhstan officially licensed by the Kazakhstan Atomic Energy Committee to provide individual dosimetry services. The Laboratory was established according to the international standards. Nowadays it is the largest company providing personal dosimetry services in the Republic of Kazakhstan. (author)

  8. 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)

  9. 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)

  10. Monte Carlo characterization of materials for prosthetic implants and dosimetric validation of Pinnacle3 TPS

    International Nuclear Information System (INIS)

    Palleri, Francesca; Baruffaldi, Fabio; Angelini, Anna Lisa; Ferri, Andrea; Spezi, Emiliano

    2008-01-01

    In external beam radiotherapy the calculation of dose distribution for patients with hip prostheses is critical. Metallic implants not only degrade the image quality but also perturb the dose distribution. Conventional treatment planning systems do not accurately account for high-Z prosthetic implants heterogeneities, especially at interfaces. The materials studied in this work have been chosen on the basis of a statistical investigation on the hip prostheses implanted in 70 medical centres. The first aim of this study is a systematic characterization of materials used for hip prostheses, and it has been provided by BEAMnrc Monte Carlo code. The second aim is to evaluate the capabilities of a specific treatment planning system, Pinnacle 3 , when dealing with dose calculations in presence of metals, also close to the regions of high-Z gradients. In both cases it has been carried out an accurate comparison versus experimental measurements for two clinical photon beam energies (6 MV and 18 MV) and for two experimental sets-up: metallic cylinders inserted in a water phantom and in a specifically built PMMA slab. Our results show an agreement within 2% between experiments and MC simulations. TPS calculations agree with experiments within 3%.

  11. Report of a consultants meeting on dosimetry in diagnostic radiology

    International Nuclear Information System (INIS)

    Pernicka, F.

    1999-01-01

    During its biennial meeting in 1996, the Standing Advisory Committee 'SSDL Scientific Committee', recommended extending the long experience of the Agency in the field of standardization and monitoring dosimetry calibrations at radiotherapy and radiation protection level for the Secondary Standard Dosimetry Laboratory (SSDL) Network, to the field of diagnostic x-ray dosimetry. It was emphasized that 'Measurements on diagnostic x-ray machines have become increasingly important and some SSDLs are involved in such measurements. The Agency's dosimetry laboratory should, therefore, have proper radiation sources available to provide traceable calibrations to the SSDLs'. The purpose of the consultants' meeting was to advise the Agency on dosimetry in diagnostic radiology. They were specifically requested to overview scientific achievements in the field and to give advice to the Agency on the need for further developments. The purpose of the consultants' meeting was to advise the Agency on dosimetry in diagnostic radiology. They were specifically requested to overview scientific achievements in the field and to give advice to the Agency on the need for further developments

  12. Alanine-EPR dosimetry system for high industrial as well radiotherapeutic dose measurement

    International Nuclear Information System (INIS)

    Dobrovodsky, J.; Bukovjan, J.

    2005-01-01

    Slovak Institute of Metrology is developing new metrology standard for high doses, based on the alanine-EPR as a reference dosimetry system. A Bruker e-scan EPR analyser developed specifically for alanine dosimetry has improved stability of EPR measurement, especially at lower dose range. The standard e-scan system provides sensitivity below 1 Gray. After further improvement of the system and lowering of dose determination expanded uncertainty down below 1 %, its utilisation for radiotherapy field is expected (authors)

  13. International symposium on standards and codes of practice in medical radiation dosimetry. Book of extended synopses

    International Nuclear Information System (INIS)

    2002-01-01

    The development of radiation measurement standards by National Metrology Institutes (NMIs) and their dissemination to Secondary Standard Dosimetry Laboratories (SSDLs), cancer therapy centres and hospitals represent essential aspects of the radiation dosimetry measurement chain. Although the demands for accuracy in radiotherapy initiated the establishment of such measurement chains, similar traceable dosimetry procedures have been implemented, or are being developed, in other areas of radiation medicine (e.g. diagnostic radiology and nuclear medicine), in radiation protection and in industrial applications of radiation. In the past few years the development of primary standards of absorbed dose to water in 60 Co for radiotherapy dosimetry has made direct calibrations in terms of absorbed dose to water available in many countries for the first time. Some laboratories have extended the development of these standards to high energy photon and electron beams and to low and medium energy x-ray beams. Other countries, however, still base their dosimetry for radiotherapy on air kerma standards. Dosimetry for conventional external beam radiotherapy was probably the field where standardized procedures adopted by medical physicists at hospitals were developed first. Those were related to exposure and air kerma standards. The recent development of Codes of Practice (or protocols) based on the concept of absorbed dose to water has led to changes in calibration procedures at hospitals. The International Code of Practice for Dosimetry Based on Standards of Absorbed Dose to Water (TRS 398) was sponsored by the International Atomic Energy Agency (IAEA), World Health Organization (WHO), Pan-American Health Organization (PAHO) and the European Society for Therapeutic Radiology and Oncology (ESTRO) and is expected to be adopted in many countries worldwide. It provides recommendations for the dosimetry of all types of beams (except neutrons) used in external radiotherapy and satisfies

  14. A neurosurgery/stereotactic radiotherapy dedicated PACS for conformal radiotherapy

    International Nuclear Information System (INIS)

    Lefkopoulos, D.; Bocquiault, P.; Levrier, M.; Merienne, L.; Schlienger, M.

    1995-01-01

    To realise conformal cerebral stereotactic irradiations we use a Neurosurgery/stereotactic dedicated PACS between two distant hospitals. It connects the stereotactic neurosurgery planification imaging system NEUROAXIS (Sopelem-Sofretec/Ste Anne Hospital) with the dosimetric TPS ARTEMIS-3D/Dosigray (Tenon Hospital). NEUROAXIS is a computer aided stereotactic biopsies and stereo-electroencephalographies, used by surgeons in operating room. The system determines the precise location data for Talairach radiological equipment (X ray source at 5 meters from film) and the geometry of scanner and MRI stereotactical referentials. It provides a full set of features for lesion localization, geometrical computations, surgical planifications, picture archiving, stereotactic angiography, CT and MRI image processing and networking. It sends images through the French public digital network ISDN (NUMERIS/France Telecom : 2x64 Kbits/s) from Ste Anne to Tenon Hospital. Stereotactic angiographic and CT images are reformatted into the DOSIGRAY image processing environment where 3-D dose distributions, displays and DVHs are computed to determine the optimal treatment. ARTEMIS-3D/Dosigray is a TPS for stereotactic radiotherapy devised by the Tenon Hospital for clinical methodology and 3D dose calculations, optimization software development and the Dosigray company for multimodality imaging, (2D(3D)) computer graphics for dose and anatomical representation and data networking. Communication within the radiation oncology department is provided by local area ETHERNET network, linking heterogeneous systems (Vaxstations-3200; Decstation (5000(240))) by means of different protocols. The works in progress are to send back via the same network the 3-D dose matrix to Neurosurgery department NEUROAXIS system. Our PACS is used since six months to treat patients. It has permitted to improve the treatment quality in comparison with our first version TPS ARTEMIS-3D

  15. Evaluation of air photoactivation at linear accelerators for radiotherapy

    International Nuclear Information System (INIS)

    Tana, Luigi; Ciolini, Riccardo; Ciuffardi, Eva; Romei, Chiara; D’Errico, Francesco

    2015-01-01

    High-energy x-rays produced by radiotherapy accelerators operating at potentials above 10 MV may activate the air via (γ, n) reactions with both oxygen and nitrogen. While the activation products are relatively short-lived, personnel entering the accelerator room may inhale some radioactive air, which warrants internal dosimetry assessments. This work illustrates a method based on the use of ammonium nitrate solutions for the evaluation of photon-induced air activation and for the estimate of internal doses to radiotherapy personnel. Air activation and internal dosimetry assessments based on our method are presented for some widespread radiotherapy linear accelerator models. Our results indicate that the equivalent dose to the lungs of radiotherapy personnel is negligible for beam energies below 18 MeV. (paper)

  16. Doses to organs at cerebral risks: optimization by robotized stereotaxic radiotherapy and automatic segmentation atlas versus three dimensional conformal radiotherapy; Doses aux organes a risque cerebraux: optimisation par radiotherapie stereotaxique robotisee et atlas de segmentation automatique versus radiotherapie conformationnelle tridimensionnelle

    Energy Technology Data Exchange (ETDEWEB)

    Bondiau, P.Y.; Thariat, J.; Benezery, K.; Herault, J.; Dalmasso, C.; Marcie, S. [Centre Antoine-Lacassagne, 06 - Nice (France); Malandain, G. [Institut National de Recherche en Informatique et en Automatique (INRIA), Sophia-Antipolis, 06 - Nice (France)

    2007-11-15

    The stereotaxic radiotherapy robotized by 'Cyberknife fourth generation' allows a dosimetric optimization with a high conformity index on the tumor and radiation doses limited on organs at risk. A cerebral automatic anatomic segmentation atlas of organs at risk are used in routine in three dimensions. This study evaluated the superiority of the stereotaxic radiotherapy in comparison with the three dimensional conformal radiotherapy on the preservation of organs at risk in regard of the delivered dose to tumors justifying an accelerated hypo fractionation and a dose escalation. This automatic segmentation atlas should allow to establish correlations between anatomy and cerebral dosimetry; This atlas allows to underline the dosimetry optimization by stereotaxic radiotherapy robotized for organs at risk. (N.C.)

  17. [Radiotherapy promises: focus on lung cancer].

    Science.gov (United States)

    Jouin, Anaïs; Durand-Labrunie, Jérôme; Leroy, Thomas; Pannier, Diane; Wagner, Antoine; Rault, Erwan; Lartigau, Eric

    2013-06-01

    Radiotherapy is a key cancer treatment, which greatly modified its practice in recent years thanks to medical imaging and technical improvements. The systematic use of computed tomography (CT) for treatment planning, the imaging fusion/co-registration between CT/magnetic resonance imaging (MRI) or CT/positron emission tomography (PET) improve target identification/selection and delineation. New irradiation techniques such as image-guided radiotherapy (IGRT), stereotactic radiotherapy or hadron therapy offer a more diverse therapeutic armamentarium to patients together with lower toxicity. Radiotherapy, as well as medical oncology, tends to offer a personalized treatment to patients thanks to the IGRT, which takes into account the inter- or intra-fraction anatomic variations. IGRT leads to adaptive radiotherapy (ART) with a new planification in the treatment course in order to decrease toxicity and improve tumor control. The use of systemic therapies with radiations needs to be studied in order to improve efficiency without increasing toxicities from these multimodal approaches. Finally, radiotherapy advances were impacted by radiotherapy accidents like Epinal. They led to an increased quality control with the intensification of identity control, the emergence of in vivo dosimetry or the experience feedback committee in radiotherapy. We will illustrate through the example of lung cancer.

  18. Reconstructive dosimetry for cutaneous radiation syndrome

    Directory of Open Access Journals (Sweden)

    C.M.A. Lima

    2015-01-01

    Full Text Available 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.

  19. MOSFET dosimetry: temperature effects in-vivo

    International Nuclear Information System (INIS)

    Yu, P.K.N.; Cheung, T.; Butson, M.J.; Cancer Services, Wollongong, NSW

    2004-01-01

    Full text: This note investigates temperature effects on dosimetry using a Metal Oxide Semiconductor Field Effect Transistor (MOSFET) for radiotherapy x-ray treatment. This was performed by analysing the dose response and threshold voltage outputs for MOSFET dosimeters as a function of ambient temperature. Results have shown the clinical semiconductor dosimetry system (CSDS) MOSFET provides stable dose measurements with temperatures varying from 15 deg C up to 40 deg C. Thus standard irradiations performed at room temperature can be directly compared to in-vivo dose assessments performed at near body temperature without a temperature correction function. The MOSFET dosimeter threshold voltage varies with temperature and this level is dependant on the dose history of the MOSFET dosimeter. However the variation can be accounted for in the measurement method. For accurate dosimetry the detector should be placed for approximately 60 seconds on a patient to allow thermal equilibrium before measurements are taken with the final reading performed whilst still attached to the patient or conversely left for approximately 120 seconds after removal from the patient if initial readout was measured at room temperature to allow temperature equilibrium to be established. Copyright (2004) Australasian College of Physical Scientists and Engineers in Medicine

  20. 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)

  1. Effects of temperature variation on MOSFET dosimetry

    International Nuclear Information System (INIS)

    Cheung Tsang; Butson, Martin J; Yu, Peter K N

    2004-01-01

    This note investigates temperature effects on dosimetry using a metal oxide semiconductor field effect transistor (MOSFET) for radiotherapy x-ray treatment. This was performed by analysing the dose response and threshold voltage outputs for MOSFET dosimeters as a function of ambient temperature. Results have shown that the clinical semiconductor dosimetry system (CSDS) MOSFET provides stable dose measurements with temperatures varying from 15 deg. C up to 40 deg. C. Thus standard irradiations performed at room temperature can be directly compared to in vivo dose assessments performed at near body temperature without a temperature correction function. The MOSFET dosimeter threshold voltage varies with temperature and this level is dependent on the dose history of the MOSFET dosimeter. However, the variation can be accounted for in the measurement method. For accurate dosimetry, the detector should be placed for approximately 60 s on a patient to allow thermal equilibrium before measurements are taken with the final reading performed whilst still attached to the patient or conversely left for approximately 120 s after removal from the patient if initial readout was measured at room temperature to allow temperature equilibrium to be established. (note)

  2. Functional Characterization of Nine Norway Spruce TPS Genes and Evolution of Gymnosperm Terpene Synthases of the TPS-d Subfamily1[w

    Science.gov (United States)

    Martin, Diane M.; Fäldt, Jenny; Bohlmann, Jörg

    2004-01-01

    Constitutive and induced terpenoids are important defense compounds for many plants against potential herbivores and pathogens. In Norway spruce (Picea abies L. Karst), treatment with methyl jasmonate induces complex chemical and biochemical terpenoid defense responses associated with traumatic resin duct development in stems and volatile terpenoid emissions in needles. The cloning of (+)-3-carene synthase was the first step in characterizing this system at the molecular genetic level. Here we report the isolation and functional characterization of nine additional terpene synthase (TPS) cDNAs from Norway spruce. These cDNAs encode four monoterpene synthases, myrcene synthase, (−)-limonene synthase, (−)-α/β-pinene synthase, and (−)-linalool synthase; three sesquiterpene synthases, longifolene synthase, E,E-α-farnesene synthase, and E-α-bisabolene synthase; and two diterpene synthases, isopimara-7,15-diene synthase and levopimaradiene/abietadiene synthase, each with a unique product profile. To our knowledge, genes encoding isopimara-7,15-diene synthase and longifolene synthase have not been previously described, and this linalool synthase is the first described from a gymnosperm. These functionally diverse TPS account for much of the structural diversity of constitutive and methyl jasmonate-induced terpenoids in foliage, xylem, bark, and volatile emissions from needles of Norway spruce. Phylogenetic analyses based on the inclusion of these TPS into the TPS-d subfamily revealed that functional specialization of conifer TPS occurred before speciation of Pinaceae. Furthermore, based on TPS enclaves created by distinct branching patterns, the TPS-d subfamily is divided into three groups according to sequence similarities and functional assessment. Similarities of TPS evolution in angiosperms and modeling of TPS protein structures are discussed. PMID:15310829

  3. Compensator design for corrector magnet power supply of TPS facility

    International Nuclear Information System (INIS)

    Wong, Y.-S.; Chen, J.-F.; Liu, K.-B.; Liu, C.-Y.; Wang, B.-S.

    2017-01-01

    From 2012 to 2015, Taiwan government has a most important technology project is Taiwan Photon Source (TPS), the total budget of TPS fund to over US300 million. It set up a synchrotron storage ring (electron energy of 3.3 GeV, circumference of 518 m, and low emittance) that provides one of the world's brightest synchrotron sources of x-rays. This study presents a compensator design for corrector magnet power supply to avoid limitations in stabilizing the frequency when the machine output current load is valid. A lead-lag compensator had been built in a full-bridge converter to improve the system bandwidth. Lead-lag compensators influence various disciplines, such as robotics, satellite control, automobile diagnostics, and laser frequency stabilization. These components are important building blocks in analog control systems and can also be used in digital control. A 50V output voltage and 10A output current prototype converter is fabricated in the laboratory. From the experimental results, the effectiveness of the control loop design can be verified from the gain margin and phase margin.

  4. Compensator design for corrector magnet power supply of TPS facility

    Science.gov (United States)

    Wong, Y.-S.; Chen, J.-F.; Liu, K.-B.; Liu, C.-Y.; Wang, B.-S.

    2017-10-01

    From 2012 to 2015, Taiwan government has a most important technology project is Taiwan Photon Source (TPS), the total budget of TPS fund to over US300 million. It set up a synchrotron storage ring (electron energy of 3.3 GeV, circumference of 518 m, and low emittance) that provides one of the world's brightest synchrotron sources of x-rays. This study presents a compensator design for corrector magnet power supply to avoid limitations in stabilizing the frequency when the machine output current load is valid. A lead-lag compensator had been built in a full-bridge converter to improve the system bandwidth. Lead-lag compensators influence various disciplines, such as robotics, satellite control, automobile diagnostics, and laser frequency stabilization. These components are important building blocks in analog control systems and can also be used in digital control. A 50V output voltage and 10A output current prototype converter is fabricated in the laboratory. From the experimental results, the effectiveness of the control loop design can be verified from the gain margin and phase margin.

  5. An in vivo investigative protocol for HDR prostate brachytherapy using urethral and rectal thermoluminescence dosimetry

    International Nuclear Information System (INIS)

    Toye, Warren; Das, Ram; Kron, Tomas; Franich, Rick; Johnston, Peter; Duchesne, Gillian

    2009-01-01

    Purpose: To develop an in vivo dosimetry based investigative action level relevant for a corrective protocol for HDR brachytherapy boost treatment. Methods and materials: The dose delivered to points within the urethra and rectum was measured using TLD in vivo dosimetry in 56 patients. Comparisons between the urethral and rectal measurements and TPS calculations showed differences, which are related to the relative position of the implant and TLD trains, and allowed shifts of implant position relative to the prostate to be estimated. Results and conclusions: Analysis of rectal dose measurements is consistent with implant movement, which was previously only identified with the urethral data. Shift corrected doses were compared with results from the TPS. Comparison of peak doses to the urethra and rectum has been assessed against the proposed corrective protocol to limit overdosing these critical structures. An initial investigative level of 20% difference between measured and TPS peak dose was established, which corresponds to 1/3 of patients which was practical for the caseload. These patients were assessed resulting in corrective action being applied for one patient. Multiple triggering for selective investigative action is outlined. The use of a single in vivo measurement in the first fraction optimizes patient benefit at acceptable cost.

  6. Treatment planning systems dosimetry auditing project in Portugal.

    Science.gov (United States)

    Lopes, M C; Cavaco, A; Jacob, K; Madureira, L; Germano, S; Faustino, S; Lencart, J; Trindade, M; Vale, J; Batel, V; Sousa, M; Bernardo, A; Brás, S; Macedo, S; Pimparel, D; Ponte, F; Diaz, E; Martins, A; Pinheiro, A; Marques, F; Batista, C; Silva, L; Rodrigues, M; Carita, L; Gershkevitsh, E; Izewska, J

    2014-02-01

    The Medical Physics Division of the Portuguese Physics Society (DFM_SPF) in collaboration with the IAEA, carried out a national auditing project in radiotherapy, between September 2011 and April 2012. The objective of this audit was to ensure the optimal usage of treatment planning systems. The national results are presented in this paper. The audit methodology simulated all steps of external beam radiotherapy workflow, from image acquisition to treatment planning and dose delivery. A thorax CIRS phantom lend by IAEA was used in 8 planning test-cases for photon beams corresponding to 15 measuring points (33 point dose results, including individual fields in multi-field test cases and 5 sum results) in different phantom materials covering a set of typical clinical delivery techniques in 3D Conformal Radiotherapy. All 24 radiotherapy centers in Portugal have participated. 50 photon beams with energies 4-18 MV have been audited using 25 linear accelerators and 32 calculation algorithms. In general a very good consistency was observed for the same type of algorithm in all centres and for each beam quality. The overall results confirmed that the national status of TPS calculations and dose delivery for 3D conformal radiotherapy is generally acceptable with no major causes for concern. This project contributed to the strengthening of the cooperation between the centres and professionals, paving the way to further national collaborations. Copyright © 2013 Associazione Italiana di Fisica Medica. Published by Elsevier Ltd. All rights reserved.

  7. Dosimetry and Calibration Section

    International Nuclear Information System (INIS)

    Otto, T.

    1999-01-01

    The Dosimetry and Calibration Section fulfils two tasks within CERN's Radiation Protection Group: the Individual Dosimetry Service monitors more than 5000 persons potentially exposed to ionizing radiation on the CERN sites, and the Calibration Laboratory verifies throughout the year, at regular intervals, over 1000 instruments, monitors, and electronic dosimeters used by RP Group. The establishment of a Quality Assurance System for the Individual Dosimetry Service, a requirement of the new Swiss Ordinance for personal dosimetry, put a considerable workload on the section. Together with an external consultant it was decided to identify and then describe the different 'processes' of the routine work performed in the dosimetry service. The resulting Quality Manual was submitted to the Federal Office for Public Health in Bern in autumn. The CERN Individual Dosimetry Service will eventually be officially endorsed after a successful technical test in March 1999. On the technical side, the introduction of an automatic development machine for gamma films was very successful. It processes the dosimetric films without an operator being present, and its built-in regeneration mechanism keeps the concentration of the processing chemicals at a constant level

  8. Study of a 3D dosimetry system response: ARCCHECK®

    Energy Technology Data Exchange (ETDEWEB)

    Mazer, Amanda C.; Yoriyaz, Hélio, E-mail: amandamazer18@gmail.com, E-mail: hyoriyaz@ipen.br [Instituto de Pesquisas Energéticas e Nucleares (IPEN/CNEN-SP), São Paulo, SP (Brazil); Nakandakari, Marcos V.N., E-mail: marcos.sake@gmail.com [Beneficência Portuguesa de São Paulo, SP (Brazil)

    2017-07-01

    Ionizing radiation therapies have improved over the years, becoming more specific for each patient. Thereby as the treatment planning system (TPS) complexities increases, the quality assurance (QA) methods have to be in a constant evolution. One of the techniques that demand great complexity is the Volumetric Modulated Arc Therapy (VMAT). One possible way to VMAT commissioning is using 3D dosimetry systems and recently a new 3D dosimetry system called ArcCheck had been developed and commercialized mainly for VMAT quality assurance. It is water-equivalent and composed by an array of 1386 diodes arranged in a spiral pattern. Since simulation methods, like Monte Carlo method, ensure highly accurate results, MCNP (A General Monte Carlo N-Particle Transport Code System) is totally reliable for problems that involve radiation transport. This work presents a preliminary study of the 3D dosimetry system ArcCheck by developing two computational models in MCNP6. In addition, experimental measures were acquired using the ArcCheck in a Linear Accelerator and then these values were compared with the results obtained by simulations of both models. The comparisons showed good reproducibility. (author)

  9. Application of extrusion-cooking for processing of thermoplastic starch (TPS)

    NARCIS (Netherlands)

    Moscicki, Leszek; Mitrus, Marcin; Wojtowicz, Agnieszka; Oniszczuk, Tomasz; Rejak, Andrzej; Janssen, Leon; Mościcki, Leszek

    Thermoplastic starch (TPS) as fully biodegradable biopolymer appeared to be one of the most useful and promising materials for packaging purpose. To obtain TPS thermal and mechanical processing should disrupt semi-crystalline starch granules. As the melting temperature of pure starch is

  10. Two year operational experience with the TPS vacuum system

    Science.gov (United States)

    Yang, Y. C.; Chan, C. K.; Sheng, I. C.; Huang, I. T.; Y Chung, J.; Liang, C. C.

    2017-07-01

    The Taiwan Photon Source (TPS), a 3-GeV third generation synchrotron light source, was commissioned in 2014 December and is now currently operated in top-up mode at 300mA for users. During the past two years, the machine was completed to meet design goals with among others the installation of superconducting cavities (SRF), the installation of insertion devices (ID) and the correction of vacuum chamber structure downstream from the IDs. The design goal of 500mA beam current was achieved with a total accumulated beam dose of more than 1000Ah, resulting in three orders of magnitude reduction of out-gassing. As the beam current was increased, a few vacuum problems were encountered, including vacuum leaks, unexpected pressure bursts, etc. Vacuum related issues including high pressure events, lessons learned and operational experience will be presented and discussed in this paper.

  11. In vivo dosimetry with silicon diodes in total body irradiation

    International Nuclear Information System (INIS)

    Oliveira, F.F.; Amaral, L.L.; Costa, A.M.; Netto, T.G.

    2014-01-01

    The aim of this work is the characterization and application of silicon diode detectors for in vivo dosimetry in total body irradiation (TBI) treatments. It was evaluated the diode response with temperature, dose rate, gantry angulations and field size. A maximum response variation of 2.2% was obtained for temperature dependence. The response variation for dose rate and angular was within 1.2%. For field size dependence, the detector response increased with field until reach a saturation region, where no more primary radiation beam contributes for dose. The calibration was performed in a TBI setup. Different lateral thicknesses from one patient were simulated and then the calibration factors were determined by means of maximum depth dose readings. Subsequent to calibration, in vivo dosimetry measurements were performed. The response difference between diode readings and the prescribed dose for all treatments was below 4%. This difference is in agreement as recommended by the International Commission on Radiation Units and Measurements (ICRU), which is ±5%. The present work to test the applicability of a silicon diode dosimetry system for performing in vivo dose measurements in TBI techniques presented good results. These measurements demonstrated the value of diode dosimetry as a treatment verification method and its applicability as a part of a quality assurance program in TBI treatments. - Highlights: ► Characterization of a silicon diode dosimetry system. ► Application of the diodes for in vivo dosimetry in total body irradiation treatments. ► Implementation of in vivo dosimetry as a part of a quality assurance program in radiotherapy

  12. INEEL Advanced Radiotherapy Research Program Annual Report for 2002

    Energy Technology Data Exchange (ETDEWEB)

    J. R. Venhuizen

    2003-05-01

    This report summarizes the activities and major accomplishments for the Idaho National Engineering and Environmental Laboratory (INEEL) Advanced Radiotherapy Research Program for calendar year 2002. Topics covered include computational dosimetry and treatment planning software development, medical neutron source development and characterization, and boron analytical chemistry.

  13. INEEL Advanced Radiotherapy Research Program Annual Report 2002

    Energy Technology Data Exchange (ETDEWEB)

    Venhuizen, J.R.

    2003-05-23

    This report summarizes the activities and major accomplishments for the Idaho National Engineering and Environmental Laboratory (INEEL) Advanced Radiotherapy Research Program for calendar year 2002. Topics covered include computational dosimetry and treatment planning software development, medical neutron source development and characterization, and boron analytical chemistry.

  14. Dosimetry for radiation processing

    DEFF Research Database (Denmark)

    Miller, Arne

    1986-01-01

    During the past few years significant advances have taken place in the different areas of dosimetry for radiation processing, mainly stimulated by the increased interest in radiation for food preservation, plastic processing and sterilization of medical products. Reference services both by intern......During the past few years significant advances have taken place in the different areas of dosimetry for radiation processing, mainly stimulated by the increased interest in radiation for food preservation, plastic processing and sterilization of medical products. Reference services both...... by international organizations (IAEA) and national laboratories have helped to improve the reliability of dose measurements. Several dosimeter systems like calorimetry, perspex, and radiochromic dye films are being improved and new systems have emerged, e.g. spectrophotometry of dichromate solution for reference...... and sterilization dosimetry, optichromic dosimeters in the shape of small tubes for food processing, and ESR spectroscopy of alanine for reference dosimetry. In this paper the special features of radiation processing dosimetry are discussed, several commonly used dosimeters are reviewed, and factors leading...

  15. Surface dose measurement with Gafchromic EBT3 film for intensity modulated radiotherapy technique

    Science.gov (United States)

    Akbas, Ugur; Kesen, Nazmiye Donmez; Koksal, Canan; Okutan, Murat; Demir, Bayram; Becerir, Hatice Bilge

    2017-09-01

    Accurate dose measurement in the buildup region is extremely difficult. Studies have reported that treatment planning systems (TPS) cannot calculate surface dose accurately. The aim of the study was to compare the film measurements and TPS calculations for surface dose in head and neck cancer treatment using intensity modulated radiation therapy (IMRT). IMRT plans were generated for 5 head and neck cancer patients by using Varian Eclipse TPS. Quality assurance (QA) plans of these IMRT plans were created on rando phantoms for surface dose measurements. EBT3 films were cut in size of 2.5 x 2.5 cm2 and placed on the left side, right side and the center of larynx and then the films were irradiated with 6 MV photon beams. The measured doses were compared with TPS. The results of TPS calculations were found to be lower compared to the EBT3 film measurements at all selected points. The lack of surface dose calculation in TPS should be considered while evaluating the radiotherapy plans.

  16. Verification of absorbed dose calculation with XIO Radiotherapy Treatment Planning System

    International Nuclear Information System (INIS)

    Bokulic, T.; Budanec, M.; Frobe, A.; Gregov, M.; Kusic, Z.; Mlinaric, M.; Mrcela, I.

    2013-01-01

    Modern radiotherapy relies on computerized treatment planning systems (TPS) for absorbed dose calculation. Most TPS require a detailed model of a given machine and therapy beams. International Atomic Energy Agency (IAEA) recommends acceptance testing for the TPS (IAEA-TECDOC-1540). In this study we present customization of those tests for measurements with the purpose of verification of beam models intended for clinical use in our department. Elekta Synergy S linear accelerator installation and data acquisition for Elekta CMS XiO 4.62 TPS was finished in 2011. After the completion of beam modelling in TPS, tests were conducted in accordance with the IAEA protocol for TPS dose calculation verification. The deviations between the measured and calculated dose were recorded for 854 points and 11 groups of tests in a homogenous phantom. Most of the deviations were within tolerance. Similar to previously published results, results for irregular L shaped field and asymmetric wedged fields were out of tolerance for certain groups of points.(author)

  17. Secondary standard dosimetry laboratory (SSDL)

    International Nuclear Information System (INIS)

    Md Saion bin Salikin.

    1983-01-01

    A secondary Standard Dosimetry Laboratory has been established in the Tun Ismail Research Centre, Malaysia as a national laboratory for reference and standardization purposes in the field of radiation dosimetry. This article gives brief accounts on the general information, development of the facility, programmes to be carried out as well as other information on the relevant aspects of the secondary standard dosimetry laboratory. (author)

  18. Conformal Radiotherapy: Physics, Treatment Planning and Verification. Proceedings book

    Energy Technology Data Exchange (ETDEWEB)

    De Wagter, C. [ed.

    1995-12-01

    The goal of conformal radiotherapy is to establish radiation dose distributions that conform tightly to the target volume in view of limiting radiation to normal tissues. Conformal radiotherapy significantly improves both local control and palliation and thus contributes to increase survival and to improve the quality of life. The subjects covered by the symposium include : (1) conformal radiotherapy and multi-leaf collimation; (2) three dimensional imaging; (3) treatment simulation, planning and optimization; (4) quality assurance; and (5) dosimetry. The book of proceedings contains the abstracts of the invited lectures, papers and poster presentations as well as the full papers of these contributions.

  19. Physical and biological basis of hadron radiotherapy. Book of abstracts

    International Nuclear Information System (INIS)

    2011-09-01

    The Workshop was a satellite event of the 14 th International Congress of Radiation Research (ICRR-2011). It was held in Cracow, Poland, on the 2 and 3 September 2011, at the Collegium Novum of the Jagiellonian University. The Workshop organized, jointly by the Institute of Nuclear Physics of the Polish Academy of Sciences and the Polish Radiation Research Society, would provide its participants with an opportunity to discuss current topics in proton and carbon radiotherapy, clinical aspects of ion radiotherapy, ion beam dosimetry, unwanted patient exposure, radiobiology for ion radiotherapy and other relevant subjects. Book of Abstracts contains abstracts of 33 oral presentations and 12 posters.

  20. Conformal Radiotherapy: Physics, Treatment Planning and Verification. Proceedings book

    International Nuclear Information System (INIS)

    De Wagter, C.

    1995-12-01

    The goal of conformal radiotherapy is to establish radiation dose distributions that conform tightly to the target volume in view of limiting radiation to normal tissues. Conformal radiotherapy significantly improves both local control and palliation and thus contributes to increase survival and to improve the quality of life. The subjects covered by the symposium include : (1) conformal radiotherapy and multi-leaf collimation; (2) three dimensional imaging; (3) treatment simulation, planning and optimization; (4) quality assurance; and (5) dosimetry. The book of proceedings contains the abstracts of the invited lectures, papers and poster presentations as well as the full papers of these contributions

  1. Influence of the curve density relative electron in dosimetry clinic in treatments stereo tactics

    International Nuclear Information System (INIS)

    Moreno Saiz, C.; Benitez Villegas, E. M.; Casado Villalon, F. J.; Parra Osorio, V.; Bodineau Gil, C.; Garcia Pareja, S.

    2013-01-01

    The objective of this study is to analyze the difference between clinical dosimetry in the treatments with radiosurgery and stereotactic radiotherapy fractional obtained from the relative Electron density curve (Schneider 1996) tabulated and provided with the scanner's radiation therapy. (Author)

  2. Nuclear medicine radiation dosimetry

    CERN Document Server

    McParland, Brian J

    2010-01-01

    Complexities of the requirements for accurate radiation dosimetry evaluation in both diagnostic and therapeutic nuclear medicine (including PET) have grown over the past decade. This is due primarily to four factors: growing consideration of accurate patient-specific treatment planning for radionuclide therapy as a means of improving the therapeutic benefit, development of more realistic anthropomorphic phantoms and their use in estimating radiation transport and dosimetry in patients, design and use of advanced Monte Carlo algorithms in calculating the above-mentioned radiation transport and

  3. REVIEW: Nuclear medicine dosimetry

    Science.gov (United States)

    Stabin, Michael

    2006-07-01

    A brief overview is provided of the history of the development of internal dose methods for use in nuclear medicine. Basic methods of internal dosimetry and the systems that have been developed for use in nuclear medicine are described. The development of the MIRD system and the International Radiopharmaceutical Dosimetry Symposium series is outlined. The evolution of models and tools for calculating dose estimates is reviewed. Current efforts in developing more patient-specific methods, particularly for use in therapy calculations, development of small scale and microdosimetry techniques, and of relating internal radiation doses to observed biological effects are described and evaluated.

  4. INDIVIDUAL DOSIMETRY SERVICE

    CERN Multimedia

    2000-01-01

    Personnel in the distribution groups Aleph, Delphi, L3, Opal who also work for other experiments than at LEP, should contact their dispatchers to explain their activities for the future, after LEP dismantling in order to be maintained on the regular distribution list at Individual DosimetryWe inform all staff and users under regular dosimetric control that the dosimeters for the monitoring period MAY/JUNE will be available from their usual dispatchers on Tuesday 2 May.Please have your films changed before the 12 May.The colour of the dosimeter valid in is MAY/JUNE is YELLOW.Individual Dosimetry Service will be closed on Friday 28 April.

  5. Dosimetry through the Secondary Laboratory of Dosimetric Calibration of Mexico

    International Nuclear Information System (INIS)

    Tovar M, V.M.; Alvarez R, J.T.; Medina O, V.P.; Vergara M, F.; Anaya M, R.; Cejudo A, J.; Salinas L, B.

    2004-01-01

    In the beginnings of the sixty years an urgent necessity is presented mainly in the developing countries, of improving in important form the accuracy in the dosimetry of external faces in therapy of radiations (radiotherapy centers), mainly in the calibration of c linical dosemeters . In 1976 the International Atomic Energy Agency, (IAEA), and the World Health Organization, (WHO), they carried out a mutual agreement with regard to the establishment and operation of a net of Secondary Patron Laboratories of Dosimetry, (LSCD). The necessity to establish measure patterns in the field of the dosimetry of the ionizing radiations, is necessary, to have an accuracy but high in the dosimetry of the radiation beams in therapy which is highly dependent of the dose given to the tumor of those patient with cancer. Similar levels of accuracy are required in protection measures to the radiation with an acceptable smaller accuracy, however, when the personal dosemeters are used to determine the doses received by the individuals under work conditions, such mensurations in therapy of radiations and radiological protection will have traceability through a chain of comparisons to primary or national patterns. The traceability is necessary to assure the accuracy and acceptability of the dosimetric measures, as well as, the legal and economic implications. The traceability is also necessary in the dosimetry of high dose like in the sterilization of different products. The main function of the LSCD is to provide a service in metrology of ionizing radiations, maintaining the secondary or national patterns, which have a traceability to the International System of measures, which is based for if same in the comparison of patterns in the Primary Laboratories of Dosimetry (LPD) under the auspice of the International Office of Weights and Measure (BIPM). The secondary and national patterns in the LSCD constitute in Mexico, the national patterns of the magnitudes in the dosimetry of the

  6. Preliminary analysis of risks in radiotherapy: concepts and application to the hospital center of Rodez; Analyse preliminaire des risques en radiotherapie: concepts et application au centre hospitalier de Rodez

    Energy Technology Data Exchange (ETDEWEB)

    Charet, J.C.; Marre, A.; Aventin, C.; Defreneix, C.; Baudrin, D.; Desroches, A. [CH Rodez, 12 - Rodez (France)

    2009-10-15

    The dosimetry, preparation and treatment steps are the weakest points in radiotherapy to make the patient secure. The preliminary risks analysis allows to clearly identify the risks types found in radiotherapy, needing a a treatment ( prevention and protection actions) to bring them to a tolerable, under control and acceptable by every body level. (N.C.)

  7. Status of radiation processing dosimetry

    DEFF Research Database (Denmark)

    Miller, A.

    1993-01-01

    Several milestones have marked the field of radiation processing dosimetry since IMRP 7. Among them are the IAEA symposium on High Dose Dosimetry for Radiation Processing and the international Workshops on Dosimetry for Radiation Processing organized by the ASTM. Several standards have been...... or are being published by the ASTM in this field, both on dosimetry procedures and on the proper use of specific dosimeter systems. Several individuals are involved in this international cooperation which contribute significantly to the broader understanding of the role of dosimetry in radiation processing....... The importance of dosimetry is emphasized in the standards on radiation sterilization which are currently drafted by the European standards organization CEN and by the international standards organization ISO. In both standards, dosimetry plays key roles in characterization of the facility, in qualification...

  8. Helical tomo-therapy in the anal canal cancer: dosimetric comparison with conformal radiotherapy with intensity modulation and classical conformal radiotherapy

    International Nuclear Information System (INIS)

    Ozsahin, M.; Ugurluer, G.; Ballerini, G.; Letenneur, G.; Zouhair, A.; Mirimanoff, R.O.

    2009-01-01

    A dosimetry comparison was made between helical tomo-therapy, I.M.R.T. and classical conformal three dimensional radiotherapy for twelve first patients that received a image guided radiotherapy, the toxicity was tackled with a minimum follow-up of fourteen months. In conclusion, the CT-guided radiotherapy allows to save organs at risks superior to I.M.R.T. and conformal radiotherapy and a best homogeneity in the target volume. the toxicity is moderated and the break time is limited. (N.C.)

  9. Glucinium dosimetry in beryl

    International Nuclear Information System (INIS)

    Kremer, M.

    1949-05-01

    The application of the method developed by Kolthoff and Sandell (1928) for the dosimetry of glucinium (beryllium) in beryl gives non-reproducible results with up to 20% discrepancies. This method recommends to separate beryllium and aluminium using 8 hydroxyquinoline and then to directly precipitate glucinium in the filtrate using ammonia. One possible reason of the problems generated by this method should be the formation of a volatile complex between beryllium and the oxine. This work shows that when the oxine is eliminated before the precipitation with ammonia the dosimetry of beryllium becomes accurate. The destruction of the oxine requires the dry evaporation of the filtrate, which is a long process. Thus the search for a reagent allowing the quantitative precipitation of beryllium in its solutions and in presence of oxine has been made. It has been verified also that the quantitative precipitation of the double beryllium and ammonium phosphate is not disturbed by the oxine in acetic buffer. This method, which gives good results, has also the advantage to separate beryllium from the alkaline-earth compounds still present in the filtrate. The report details the operation mode of the method: beryllium dosimetry using ammonium phosphate, aluminium-beryllium separation, application to beryl dosimetry (ore processing, insolubilization of silica, precipitation with ammonia, precipitation with oxine, precipitation of PO 4 NH 4 Gl, preciseness). (J.S.)

  10. Group: radiation dosimetry

    International Nuclear Information System (INIS)

    Caldas, L.V.E.

    1990-01-01

    The main activities of the radiation dosimetry group is described, including the calibration of instruments, sources and radioactive solutions and the determination of neutron flux; development, production and market dosimetric materials; development radiation sensor make the control of radiation dose received by IPEN workers; development new techniques for monitoring, etc. (C.G.C.)

  11. Solid state radiation dosimetry

    International Nuclear Information System (INIS)

    Moran, P.R.

    1976-01-01

    Important recent developments provide accurate, sensitive, and reliable radiation measurements by using solid state radiation dosimetry methods. A review of the basic phenomena, devices, practical limitations, and categories of solid state methods is presented. The primary focus is upon the general physics underlying radiation measurements with solid state devices

  12. INDIVIDUAL DOSIMETRY SERVICE

    CERN Multimedia

    2002-01-01

    Deadline...Deadline...Deadline...Deadline...Deadline...Deadline...   Individual dosimetry service We inform all staffs and users under regular dosimetric control that the dosimeters for the monitoring period JANUARY/FEBRUARY 2002 are available from their usual dispatchers. Please have your films changed before the 15th of January. The color of the dosimeter valid in JANUARY/FEBRUARY is WHITE.

  13. 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.

  14. Individual dosimetry service

    CERN Document Server

    2004-01-01

    We inform all staff and users under regular dosimetry control that the dosimeters for the monitoring period JULY-AUGUST 2004 are available from their usual dispatchers. Please have your films changed before the 15 JULY 2004. The color of the dosimeter valid in July-August 2004 is PINK.

  15. In vivo thermoluminescent dosimetry in studies of helicoid computed tomography and excretory urogram

    International Nuclear Information System (INIS)

    Cruz C, D.; Azorin N, J.; Saucedo A, V.M.; Barajas O, J.L.

    2005-01-01

    The dosimetry is the field of measurement of the ionizing radiations. It final objective is to determine the 'absorbed dose' for people. The dosimetry is vital in the radiotherapy, the radiological protection and the treatment technologies by irradiation. Presently work, we develop 'In vivo' dosimetry, in exposed patients to studies of helical computed tomography and excretory urogram. The dosimetry 'in vivo' was carried out in 20 patients selected aleatorily, for each medical study. The absorbed dose was measured in points of interest located in crystalline, thyroid, chest and abdomen of each patient, by means of thermoluminescent dosemeters (TLD) LiF: Mg,Cu,P + Ptfe of national fabrication. Also it was quantified the dose in the working area. (Author)

  16. Radiation protection and dosimetry: basis. 9. ed.

    International Nuclear Information System (INIS)

    Tauhata, Luiz; Salati, Ivan; Di Prinzio, Renato; Di Prinzio, Antonieta R.

    2013-11-01

    A revised book 'Radiation Protection and Dosimetry: Fundamentals , prepared to meet the training courses offered by the Instituto de Radioprotecao e Dosimetria - IRD, Rio de Janeiro, RJ, Brazil and people interested in the subject, is presented. Concepts have been updated, especially the chapter on Radiological Magnitudes, due to upgrade of Standard CNEN-NN-3.01-Basic Guidelines on Radiological Protection, published in the Diario Oficial da Uniao on September 1, 2011. A chapter related to Waste Management, another on the Transport of Radioactive Materials and three annexes on: Standards of CNEN, Ionizing Radiation and Personnel Legislation and Determination of shields in Radiotherapy were included. Were also added several tables for use in radiological protection, to facilitate consultation

  17. Review of common accidents in external beam radiotherapy

    International Nuclear Information System (INIS)

    Ombogo, C.M

    2015-02-01

    This work covers patients protection in Radiotherapy which is a multi step procedure that is complex. Any error in any step has an effect on the patient and therefore the entire process requires attention to details in order to achieve patients protection. This project reviews eight case studies involving accidents that occurred during the process of therapy delivery. Professionalism in case one and two was not practiced in that in case one medical physicist failed to calculate decay data instead relied on incorrect decay graph thus giving wrong dose. While in case two a wrong TPS was approved following a formal written procedure due to new technology. In case three and seven there was a software malfunction due to uniformed choice of TPS and in case four a computer file was not updated in the TPS while in eight the failure is inter look system led to patients recieving high dose than was prescribed. Calibration in case five and six was due to wrong actions in both repairs and interpretation of treatment time than the overdose to patient. The lessen learnt seeks to act as a checklist for ensuring patient protection in radiotherapy and prevention of future accidents. (au)

  18. Friction and wear of TPS fibers. Progress Report

    International Nuclear Information System (INIS)

    Bascom, W.D.; Wong, S.

    1987-11-01

    The sliding friction behavior of single filaments of SiO 2 , SiC, and an aluminoborosilicate has been determined. These fibers are used in thermal protection systems (TPS) and are subject to damage during weaving and aero-maneuvering. All fibers exhibited stick-slip friction indicating the successive formation and rupture of strong junctions between the contacting filaments. The static frictional resistance of the sized SiC filament was 4X greater than for the same filament after heat cleaning. This result suggests that the sizing is an organic polymer with a high shear yield strength. Heat cleaning exposes the SiC surface and/or leaves an inorganic residue so that the adhesional contact between filaments has a low fracture energy and frictional sliding occurs by brittle fracture. The frictional resistances of the sized and heat cleaned SiO 2 and glass filaments were all comparable to that of the heat cleaned SiC. It would appear that the sizings as well as the heat cleaned surfaces of the silica and glass have low fracture energies so that the sliding resistance is determined by brittle fracture

  19. Clinical research of teeth damage from radiotherapy

    International Nuclear Information System (INIS)

    Li Erzhou; Yan Maosheng; Chen Wei; Li Qing

    2003-01-01

    Objective: To analyze various factors inducing teeth damage from radiotherapy and the preventive and treatment methods. Methods: One hundred cases of patients treated by radiotherapy were divided into two groups. In group one there were 60 cases whose teeth were irradiated during treatment; in group two there were 40 cases whose teeth were not irradiated during treatment. Results: The caries incidence was 60% for group one and 15% for group two (P<0.01). By auto-control in 15 patients, the caries incidence on the sick side was obviously higher than that of the healthy side. Hundred percent caries incidence was found in 6 cases who received a dosage of 70 Gy. Conclusion: The authors believe that radiation damage to the teeth is associated with the following factors: 1. The dosage and location of irradiation are closely related to caries incidence; 2. The active dentinoblasts are very sensitive to radiation; 3. Damage to the salivary glands from radiotherapy can result in reduction of salvia and pH value, leading to a high growth rate of Streptococcus mutans. Following preventive measures could be considered in future cases: to apply a caries prevention coating or protective dental crown and TPS, to adjust the dose and time of irradiation, to select conformal radiotherapy technique. The key points for protecting the teeth and salivary gland from caries and damage are protection of the proliferation ability of pulp cells, anti-inflammation, promotion of microcirculation, and strengthening body resistance

  20. WE-AB-201-03: TPS Commissioning and QA: Incorporating the Entire Planning Process

    International Nuclear Information System (INIS)

    Mutic, S.

    2015-01-01

    Treatment planning systems (TPS) are a cornerstone of modern radiation therapy. Errors in their commissioning or use can have a devastating impact on many patients. To support safe and high quality care, medical physicists must conduct efficient and proper commissioning, good clinical integration, and ongoing quality assurance (QA) of the TPS. AAPM Task Group 53 and related publications have served as seminal benchmarks for TPS commissioning and QA over the past two decades. Over the same time, continuing innovations have made the TPS even more complex and more central to the clinical process. Medical goals are now expressed in terms of the dose and margins around organs and tissues that are delineated from multiple imaging modalities (CT, MR and PET); and even temporally resolved (i.e., 4D) imaging. This information is passed on to optimization algorithms to establish accelerator movements that are programmed directly for IMRT, VMAT and stereotactic treatments. These advances have made commissioning and QA of the TPS much more challenging. This education session reviews up-to-date experience and guidance on this subject; including the recently published AAPM Medical Physics Practice Guideline (MPPG) #5 “Commissioning and QA of Treatment Planning Dose Calculations: Megavoltage Photon and Electron Beams”. Treatment Planning System Commissioning and QA: Challenges and Opportunities (Greg Salomons) This session will provide some key background and review publications describing prominent incidents relating to TPS commissioning and QA. Traditional approaches have been hardware and feature oriented. They aim to establish a functional configuration and establish specifications for regular testing of features (like dose calculation) to assure stable operation and detect failures. With the advent of more complex systems, more patient-specific testing has also been adopted. A number of actual TPS defects will be presented along with heuristics for identifying similar

  1. Clinical radionuclide therapy dosimetry: the quest for the ''Holy Gray''

    Energy Technology Data Exchange (ETDEWEB)

    Brans, B. [University Hospital Maastricht, Department of Nuclear Medicine, P.O. Box 5800, Maastricht (Netherlands); Bodei, L. [Istituto Europeo di Oncologia, Division of Nuclear Medicine, Milan (Italy); Giammarile, F. [Service de Medecine Nucleaire, Centre Leon Berard, Lyon (France); Linden, O.; Tennvall, J. [Lund University Hospital, Department of Oncology, Lund (Sweden); Luster, M. [University of Wuerzburg, Department of Nuclear Medicine, Wuerzburg (Germany); Oyen, W.J.G. [University Medical Center Nijmegen, Department of Nuclear Medicine, Nijmegen (Netherlands)

    2007-05-15

    Radionuclide therapy has distinct similarities to, but also profound differences from external radiotherapy. This review discusses techniques and results of previously developed dosimetry methods in thyroid carcinoma, neuro-endocrine tumours, solid tumours and lymphoma. In each case, emphasis is placed on the level of evidence and practical applicability. Although dosimetry has been of enormous value in the preclinical phase of radiopharmaceutical development, its clinical use to optimise administered activity on an individual patient basis has been less evident. In phase I and II trials, dosimetry may be considered an inherent part of therapy to establish the maximum tolerated dose and dose-response relationship. To prove that dosimetry-based radionuclide therapy is of additional benefit over fixed dosing or dosing per kilogram body weight, prospective randomised phase III trials with appropriate end points have to be undertaken. Data in the literature which underscore the potential of dosimetry to avoid under- and overdosing and to standardise radionuclide therapy methods internationally are very scarce. In each section, particular developments and insights into these therapies are related to opportunities for dosimetry. The recent developments in PET and PET/CT imaging, including micro-devices for animal research, and molecular medicine provide major challenges for innovative therapy and dosimetry techniques. Furthermore, the increasing scientific interest in the radiobiological features specific to radionuclide therapy will advance our ability to administer this treatment modality optimally. (orig.)

  2. Innovative Reduced Mass TPS Designs for Human-Rated Aeroassit Vehicles, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — This proposal addresses Item #2 of Topic X7.04 Aeroassist Systems and proposes innovative heat shield thermal protection systems (TPS) designs for human-rated...

  3. [Development of a Software for Automatically Generated Contours in Eclipse TPS].

    Science.gov (United States)

    Xie, Zhao; Hu, Jinyou; Zou, Lian; Zhang, Weisha; Zou, Yuxin; Luo, Kelin; Liu, Xiangxiang; Yu, Luxin

    2015-03-01

    The automatic generation of planning targets and auxiliary contours have achieved in Eclipse TPS 11.0. The scripting language autohotkey was used to develop a software for automatically generated contours in Eclipse TPS. This software is named Contour Auto Margin (CAM), which is composed of operational functions of contours, script generated visualization and script file operations. RESULTS Ten cases in different cancers have separately selected, in Eclipse TPS 11.0 scripts generated by the software could not only automatically generate contours but also do contour post-processing. For different cancers, there was no difference between automatically generated contours and manually created contours. The CAM is a user-friendly and powerful software, and can automatically generated contours fast in Eclipse TPS 11.0. With the help of CAM, it greatly save plan preparation time and improve working efficiency of radiation therapy physicists.

  4. USAF TPS L-23 Super Blanik Aerodynamic Determination, Evaluation, and Reporting Program (HAVE BLADDER)

    National Research Council Canada - National Science Library

    Yam-Shahor, Aviv; Smith, Eric; Dabrowski, Vincent; Cain, Scott; Woodcock, Michele; Wilson, Benjamin

    2005-01-01

    The HAVE BLADDER TMP was conducted at the request of the USAF TPS as part of a NASA investigation into the viability of UAV endurance enhancement through the extraction of energy from atmospheric wind gradients...

  5. Automated Design and Analysis Tool for CEV Structural and TPS Components, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — The innovation of the proposed effort is a unique automated process for the analysis, design, and sizing of CEV structures and TPS. This developed process will...

  6. Low Intrusive Fiber Optic-Plug for TPS Materials, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — Heat shield technology is a critical component of manned spaceflight. In particular, the new Crew Exploration Vehicle (CEV) requires thermal protection systems (TPS)...

  7. Flexible Ablative Aerogel TPS Materials for Planetary Aerocapture and Entry, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — Renewed interest in missions to explore other planets has created a need for higher performance thermal protection systems (TPS) capable of shielding spacecraft from...

  8. USAF TPS L-23 Shear Wind Observed Optimized Path Investigation for NASA (SENIOR ShWOOPIN)

    National Research Council Canada - National Science Library

    Gordon, Randy; Fails, Robert; Baase, Solomon; Eckberg, Jason; Ryan, Charles; Smith, Chris

    2006-01-01

    The SENIOR ShWOOPIN TMP was conducted at the request of the USAF TPS as part of a NASA investigation into the viability of aircraft endurance enhancement through the extraction of energy from horizontal wind gradients...

  9. Investigating the Thermochemical Response of Avcoat TPS from First Principles for Comparison with EFT-1 Data

    Data.gov (United States)

    National Aeronautics and Space Administration — The objective of our work is to develop improved thermal response models of the AVCOAT thermal protection system (TPS) from first principles, and to validate the...

  10. TPS Failure Modes and Margins, and Architectural Concepts to Maximize Entry Reliability

    Data.gov (United States)

    National Aeronautics and Space Administration — This study will generate data to be used in a Risk Informed Decision Making (RIDM) framework that will evaluate the current MSR EEV baseline aeroshell TPS material,...

  11. Patient Radiation Protection in Radiotherapy

    International Nuclear Information System (INIS)

    Hegazy, M.

    2010-01-01

    The Role of Radiotherapy is treatment modalities for cancer which is generally assumed that 50 to 60% of cancer patients will benefit from radiotherapy. It constitutes a peaceful application of ionizing radiation and an essential part of cancer management. The two aims of radiation protection Prevention is of deterministic effect and Reduction of the probability of stochastic effects. The Shielding fundamentals is to limit radiation exposure of staff, patients, visitors and the public to acceptable levels it also optimize protection of patients, staff and the public. Diagnosis is important for target design and the dose required for cure or palliation while Simulator is often used twice in the radiotherapy process where Patient data acquisition - target localization, contours, outlines and Verification. The Prescription is the responsibility of individual clinicians, depending on the patient’s condition, equipment available, experience and training. An ultimate check of the actual treatment given can only be made by using in vivo dosimetry. Treatment records must be kept of all relevant aspects of the treatment – including Session and Summary Record information, Records all treatment parameters, Dose Calculations and Dose Measurements

  12. Proton dosimetry intercomparison

    International Nuclear Information System (INIS)

    Vatnitsky, S.; Siebers, J.; Miller, D.; Moyers, M.; Schaefer, M.; Jones, D.; Vynckier, S.; Hayakawa, Y.; Delacroix, S.; Isacsson, U.; Medin, J.; Kacperek, A.; Lomax, A.; Coray, A.; Kluge, H.; Heese, J.; Verhey, L.; Daftari, I.; Gall, K.; Lam, G.; Beck, T.; Hartmann, G.

    1996-01-01

    Background and purpose: Methods for determining absorbed dose in clinical proton beams are based on dosimetry protocols provided by the AAPM and the ECHED. Both groups recommend the use of air-filled ionization chambers calibrated in terms of exposure or air kerma in a 60 Co beam when a calorimeter or Faraday cup dosimeter is not available. The set of input data used in the AAPM and the ECHED protocols, especially proton stopping powers and w-value is different. In order to verify inter-institutional uniformity of proton beam calibration, the AAPM and the ECHED recommend periodic dosimetry intercomparisons. In this paper we report the results of an international proton dosimetry intercomparison which was held at Loma Linda University Medical Center. The goal of the intercomparison was two-fold: first, to estimate the consistency of absorbed dose delivered to patients among the participating facilities, and second, to evaluate the differences in absorbed dose determination due to differences in 60 Co-based ionization chamber calibration protocols. Materials and methods: Thirteen institutions participated in an international proton dosimetry intercomparison. The measurements were performed in a 15-cm square field at a depth of 10 cm in both an unmodulated beam (nominal accelerator energy of 250 MeV) and a 6-cm modulated beam (nominal accelerator energy of 155 MeV), and also in a circular field of diameter 2.6 cm at a depth of 1.14 cm in a beam with 2.4 cm modulation (nominal accelerator energy of 100 MeV). Results: The results of the intercomparison have shown that using ionization chambers with 60 Co calibration factors traceable to standard laboratories, and institution-specific conversion factors and dose protocols, the absorbed dose specified to the patient would fall within 3% of the mean value. A single measurement using an ionization chamber with a proton chamber factor determined with a Faraday cup calibration differed from the mean by 8%. Conclusion: The

  13. Dosimetry for food irradiation

    International Nuclear Information System (INIS)

    2002-01-01

    A Manual of Food Irradiation Dosimetry was published in 1977 under the auspices of the IAEA as Technical Reports Series No. 178. It was the first monograph of its kind and served as a reference in the field of radiation processing and in the development of standards. While the essential information about radiation dosimetry in this publication has not become obsolete, other publications on radiation dosimetry have become available which have provided useful information for incorporation in this updated version. There is already a Codex General Standard for Irradiated Foods and an associated Code of Practice for Operation of Irradiation Facilities used for Treatment of Food, issued in 1984 by the Codex Alimentarius Commission of the FAO/WHO Food Standard Programme. The Codex Standard contains provisions on irradiation facilities and process control which include, among other requirements, that control of the processes within facilities shall include the keeping of adequate records including quantitative dosimetry. Appendix A of the Standard provides an explanation of process control and dosimetric requirements in compliance with the Codex Standard. By 1999, over 40 countries had implemented national regulations or issued specific approval for certain irradiated food items/classes of food based on the principles of the Codex Standard and its Code of Practice. Food irradiation is thus expanding, as over 30 countries are now actually applying this process for the treatment of one or more food products for commercial purposes. Irradiated foods are being marketed at retail level in several countries. With the increasing recognition and application of irradiation as a sanitary and phytosanitary treatment of food based on the provisions of the Agreement on the Application of Sanitary and Phytosanitary Measures of the World Trade Organization, international trade in irradiated food is expected to expand during the next decade. It is therefore essential that proper dosimetry

  14. Saliva CA125 and TPS levels in patients with oral squamous cell carcinoma.

    Science.gov (United States)

    Geng, Xue-fei; Du, Meng; Han, Jing-xiu; Zhang, Min; Tang, Xiao-fei; Xing, Ru-dong

    2013-01-01

    To determine the levels of carbohydrate antigen 125 (CA125) and tissue polypeptide-specific antigen (TPS) in saliva of patients with oral squamous cell carcinoma (OSCC) and patients with nonneoplastic disease of the oral cavity, and to investigate their diagnostic value and their relationship with pathological grade and clinical stage. A total of 97 hospitalized patients with OSCC, 36 patients with nonneoplastic disease of the oral cavity and 50 healthy individuals were included in this investigation. Mixed saliva was collected from these patients and the healthy controls before treatment. Saliva samples were analyzed by enzyme-linked immunosorbent assay (ELISA). The saliva CA125 and TPS concentrations were significantly higher in patients with OSCC than in patients with nonneoplastic disease and healthy controls, but not significantly different between patients with nonneoplastic disease and controls. Neither the saliva CA125 nor the TPS level was correlated with pathological grade and clinical stage. The sensitivity, specificity and accuracy of saliva CA125 and TPS for the diagnosis of OSCC were 80.0%, 66.0%, 75.7%, and 82.1%, 74.0%, 79.3%, respectively. When CA125 and TPS were analyzed independently, there was no significant difference in sensitivity, specificity and accuracy between the two markers. When CA125 and TPS were analyzed in combination, there was no significant difference in sensitivity, specificity and accuracy between independent detection and combined detection. The saliva CA125 and TPS concentrations were elevated in patients with OSCC. CA125 and TPS may prove to be useful tumor markers in OSCC.

  15. Diamond dosimetry: Outcomes of the CANDIDO and CONRAD INFN projects

    International Nuclear Information System (INIS)

    Bucciolini, M.; Borchi, E.; Bruzzi, M.; Casati, M.; Cirrone, P.; Cuttone, G.; De Angelis, C.; Lovik, I.; Onori, S.; Raffaele, L.; Sciortino, S.

    2005-01-01

    This paper reviews the main results of the study, carried out in the framework of the Italian National Institute of Nuclear Physics (INFN, Istituto Nazionale di Fisica Nucleare) projects, namely CANDIDO and CONRAD, on natural and synthetic diamond-based dosimeters for clinical radiotherapy. Characteristics of diamond such as radiation hardness, high sensitivity, tissue equivalence, etc., make this material interesting for dosimetry applications. For some years, natural diamonds have been commercially available for on-line radiotherapy dosimetry. Nevertheless, recent developments in the 'Chemical Vapour Deposition' (CVD) technique have addressed the attention on synthetic samples that potentially could be grown at low cost and with features suitable for dosimetric use. Several samples, differently grown and with different electrical contacts, have been compared by measuring their current response during irradiation with high-energy photon, electron and proton beams. Properties of dosimetric interest such as linearity, pre-irradiation dose, dose rate dependence, stability and rise time have been investigated. The results obtained so far within the INFN collaboration demonstrate the suitability of natural diamond detectors for many radiotherapy applications and the great potential of CVD diamond-based devices even though, at present, the commercial natural diamond dosimeters have a better behaviour with respect to the synthetic samples. Further efforts have to be made mainly to improve the dynamic of response and performance stability

  16. IAEA/WHO postal dose audits for radiotherapy hospitals in Eastern and South-Eastern Europe

    International Nuclear Information System (INIS)

    Izewska, J.; Vatnitsky, S.; Shortt, K.R.

    2004-01-01

    The IAEA/WHO TLD programme has been in operation for 34 years. In this period the calibration of approximately 5200 high-energy photon beams in over 1300 radiotherapy hospitals in 115 countries worldwide was checked. Of these, 18% of the audits were performed in Eastern and South-Eastern Europe. There are large contrasts in the region; while the results are very good for most countries, a few countries struggle with basic problems in dosimetry. The hospitals operating radiotherapy services without qualified medical physicists or dosimetry equipment have poorer results than those properly equipped and staffed. Only about 2/3 of TLD audit participants in Eastern Europe have the appropriate dosimetry equipment. To achieve consistency of the audit results within Eastern and South-Eastern Europe, strengthening of radiotherapy infrastructure in a few countries would be necessary. (authors)

  17. Radiotherapy Accidents

    Science.gov (United States)

    Mckenzie, Alan

    A major benefit of a Quality Assurance system in a radiotherapy centre is that it reduces the likelihood of an accident. For over 20 years I have been the interface in the UK between the Institute of Physics and Engineering in Medicine and the media — newspapers, radio and TV — and so I have learned about radiotherapy accidents from personal experience. In some cases, these accidents did not become public and so the hospital cannot be identified. Nevertheless, lessons are still being learned.

  18. Radiotherapy apparatus

    International Nuclear Information System (INIS)

    Leung, P.M.; Webb, H.P.J.

    1985-01-01

    This invention relates to apparatus for applying intracavitary radiotherapy. In previously-known systems radioactive material is conveyed to a desired location within a patient by transporting a chain of balls pneumatically to and from an appropriately inserted applicator. According to this invention a ball chain for such a purpose comprises several radioactive balls separated by non-radioactive tracer balls of radiographically transparent material of lower density and surface hardness than the radioactive balls. The invention also extends to radiotherapy treatment apparatus comprising a storage, sorting and assembly system

  19. Organization of teletherapy treatment planning training process for medical physicists and engineers of radiotherapy departments at N.N. Alexandrov national cancer centre of Belarus

    International Nuclear Information System (INIS)

    Titovich, E.V.; Gertsik, O.A.; Potepalov, P.O.; Tarutin, I.G.; Gatskevich, G.V.

    2017-01-01

    Training was provided for all employees of the Radiotherapy engineering and medical physics department of the N.N. Alexandrov NCCB in accordance with their job duties. The developed instruction describes the following procedures for the operation of equipment for radiation therapy: CT and PET images registration procedure, analysis of the treatment planning statistics, import of the patient data to the Eclipse TPS, patient data transfer from CT to the dedicated data server, CT and MRI images registration procedure, 3D treatment planning using MasterPlan TPS, 3D treatment planning using Eclipse TPS, IMRT and VMAT verification using EPID, IMRT and VMAT verification using Octavius 4D, EPID calibrations, IMRT treatment planning using Eclipse TPS, VMAT treatment planning using Eclipse TPS. Conclusions. Introduction of the developed instruction in the clinical practice of N.N. Alexandrov NCCB made it possible to streamline the process of training the staff of the Radiotherapy engineering and medical physics department and to competently approach the evaluation of the knowledge acquired by the personnel that is operating of the radiotherapy equipment

  20. Modern methods of personnel dosimetry

    International Nuclear Information System (INIS)

    Kraus, W.; Herrmann, D.; Kiesewetter, W.

    The physical properties of radiation detectors for personnel dosimetry are described and compared. The suitability of different types of dosimeters for operational and central monitoring of normal occupational exposure, for accident and catastrophe dosimetry and for background and space-flight dosimetry is discussed. The difficulties in interpreting the dosimeter reading with respect to the dose in individual body organs are discussed briefly. 430 literature citations (up to Spring 1966) are given

  1. The dosimetry of ionizing radiation

    CERN Document Server

    1990-01-01

    A continuation of the treatise The Dosimetry of Ionizing Radiation, Volume III builds upon the foundations of Volumes I and II and the tradition of the preceeding treatise Radiation Dosimetry. Volume III contains three comprehensive chapters on the applications of radiation dosimetry in particular research and medical settings, a chapter on unique and useful detectors, and two chapters on Monte Carlo techniques and their applications.

  2. PENINGKATAN MOTIVASI DAN HASIL BELAJAR MELALUI THINK PAIR SHARE (TPS DI SEKOLAH DASAR

    Directory of Open Access Journals (Sweden)

    Erika Puspitasari

    2016-07-01

    Full Text Available This study aims to improve motivation and learning outcomes through the Think Pair Share (TPS. Subjects were students of class IV SDN Margomulyo 02 Blitar. Type of research is classroom action research. Collecting data using questionnaires and test sheets. Data were analyzed using descriptive analysis. Results penilitian namely (1 there is an increased motivation to learn through TPS with an average score of the first cycle to the second cycle of 18%. (2 there is an increase learning outcomes through TPS with an average score of the first cycle to the second cycle by 14%. Advice given more time guiding students through group discussion so that students can actively work together in groups. Penelitian ini bertujuan untuk meningkatan motivasi dan hasil belajar melalui Think Pair Share (TPS. Subyek penelitian adalah siswa kelas IV SDN Margomulyo 02 Blitar. Jenis penelitiannya adalah penelitian tindakan kelas. Pengumpulan data menggunakan lembar angket dan tes. Teknik analisis data menggunakan analisis deskriptif. Hasil penilitian yaitu (1 terdapat peningkatan motivasi belajar melalui TPS dengan skor rata-rata siklus I ke siklus II sebesar 18%. (2 terdapat peningkatan hasil belajar melalui TPS dengan skor rata-rata siklus I ke siklus II sebesar 14%. Saran yang diberikan lebih membimbing siswa saat diskusi kelompok agar siswa secara aktif dapat bekerja sama dalam kelompok.

  3. Assessment of TPS tumor marker with ELISA for early detection and monitoring of gastrointestinal cancers

    Directory of Open Access Journals (Sweden)

    Salehi Nodeh A.R

    2007-05-01

    Full Text Available Background: TPS is one of the tumor markers which has specially been considered due to its exclusive physiological characteristics like its easy measurement in serum of cancer patients. This study has been due to evaluate the efficiency of this tumor marker in the prognosis, treatment control and follow up of patients with gastrointestinal cancers including esophagus, stomach and colorectal. Methods: TPS has been measured in 109 persons including 28 healthy people and 81 patients with different gastrointestinal malignancies which were composed of 38 patients with esophageal cancer, 20 ones with stomach cancer and 23 ones with colorectal cancer. Sampling has been done in three times depending on treatment methods. TPS has been measured with ELISA in samples which contend of 2 to 3 ml of serum from patients and the health. Results: The obtained results, demonstrate the obvious changes in TPS serum level in patients underwent various treatment procedures. Conclusion: The results have revealed that the serum TPS is not only as a measure of prognosis but also would be helpful in follow up and treatment control of the disease. Moreover the results has shown that serological analysis can be settled in the diagnosis and follow up with production of polyclonal antibody against TPS gene family and planning appropriate pattern.

  4. Interlaboratory niobium dosimetry comparison

    International Nuclear Information System (INIS)

    Wille, P.

    1980-01-01

    For an interlaboratory comparison of neutron dosimetry using niobium the 93 sup(m)Nb activities of irradiated niobium monitors were measured. This work was performed to compare the applied techniques of dosimetry with Nb in different laboratories. The niobium monitors were irradiated in the fast breeder EBRII, USA and the BR2, Belgium. The monitors were dissolved and several samples were prepared. Their niobium contents were determined by the 94 Nb-count rates. since the original specific count rate was known. The KX radiations of the 93 sup(m)Nb of the samples and of a calibrated Nb-foil were compared. This foil was measured by PTB, Braunschweig and CBNM, Geel, which we additionally compared with the KX radiation of 88 Sr produced by a thin 88 Y source from a 88 Y-standard solution (PTB). (orig.) [de

  5. Neutron beam measurement dosimetry

    International Nuclear Information System (INIS)

    Amaro, C.R.

    1995-01-01

    This report describes animal dosimetry studies and phantom measurements. During 1994, 12 dogs were irradiated at BMRR as part of a 4 fraction dose tolerance study. The animals were first infused with BSH and irradiated daily for 4 consecutive days. BNL irradiated 2 beagles as part of their dose tolerance study using BPA fructose. In addition, a dog at WSU was irradiated at BMRR after an infusion of BPA fructose. During 1994, the INEL BNCT dosimetry team measured neutron flux and gamma dose profiles in two phantoms exposed to the epithermal neutron beam at the BMRR. These measurements were performed as a preparatory step to the commencement of human clinical trials in progress at the BMRR

  6. Computerized planning and dosimetry for brachytherapy in carcinomas cervix

    International Nuclear Information System (INIS)

    Kizilbash, N.A.; Jabeen, K.; Hussain, R.

    1996-01-01

    A project on the use of computerize planning and dosimetry for brachytherapy in carcinoma of cervix was started at NORI (Nuclear Medicine, Oncology and Radiotherapy Institute, Islamabad) in september 1990. A total number of 182 patients were included in the study over a period of three years. The treatment of all these patients was done by external radiation as well as the intracavitary therapy. Planning and dosimetry was done according to ICRU 38 recommendations. 70 patients were planned with two computers TP-II (Dr. J. Cunningham's software) and PC based system (Dr. Kallinger's software, BTI system). From the results of the two computers TP-II and PC, it can be seen that the difference in a absorbed dose for all recommended points in not going to harm the patient. The dose to the bladder and the rectum in our studies is quite low because of the low activity in the ovoid sources. (author)

  7. The dosimetry of ionizing radiation

    CERN Document Server

    Bjaerngard, Bengt E; Kase, Kenneth R

    1987-01-01

    The Dosimetry of Ionizing Radiation, Volume II, attempts to fill the need for updated reference material on the field of radiation dosimetry. This book presents some broad topics in dosimetry and a variety of radiation dosimetry instrumentation and its application. The book opens with a chapter that extends and applies the concepts of microdosimetry to biological systems. This is followed by separate chapters on the state- of-the-art equipment and techniques used to determine neutron spectra; studies to determine recombination effects in ionization chambers exposed to high-intensity pulsed ra

  8. Sixth symposium on neutron dosimetry

    International Nuclear Information System (INIS)

    1987-01-01

    This booklet contains all abstracts of papers presented in 13 sessions. Main topics: Cross sections and Kerma factors; analytical radiobiology; detectors for personnel monitoring; secondary charged particles and microdosimetric basis of q-value for neutrons; personnel dosimetry; concepts for radiation protection; ambient monitoring; TEPC and ion chambers in radiation protection; beam dosimetry; track detectors (CR-39); dosimetry at biomedical irradiation facilities; health physics at therapy facilities; calibration for radiation protection; devices for beam dosimetry (TLD and miscellaneous); therapy and biomedical irradiation facilities; treatment planning. (HP)

  9. Personnel radiation dosimetry

    International Nuclear Information System (INIS)

    1987-01-01

    The book contains the 21 technical papers presented at the Technical Committee Meeting to Elaborate Procedures and Data for the Intercomparison of Personnel Dosimeters organizaed by the IAEA on 22-26 April 1985. A separate abstract was prepared for each of these papers. A list of areas in which additional research and development work is needed and recommendations for an IAEA-sponsored intercomparison program on personnel dosimetry is also included

  10. Dosimetry for Crystals Irradiation

    CERN Document Server

    Lecomte, Pierre

    2005-01-01

    Before shipment to CMS, all PbWO4 crystals produced in China are irradiated there with 60 Co , in order to insure that the induced absorption coefficient is within specifications. Acceptance tests at CERNand at ENEA also include irradiation with gamma rays from 60 Co sources. There were initially discrepancies in quoted doses and doserates as well as in induced absorption coefficients. The present work resolves the discrepancies in irradiation measurements and defines common dosimetry methods for consistency checks between irradiation facilities.

  11. Thermoluminescence dosimetry and its applications in medicine. Part 2: history and applications

    International Nuclear Information System (INIS)

    Kron, T.

    1995-01-01

    Thermoluminescence dosimetry (TLD) has been available for dosimetry of ionising radiation for nearly 100 years. The variety of materials and their different physical forms allow the determination of different radiation qualities over a wide range of absorbed dose. This makes TL dosimeters useful in radiation protection where dose levels of μ Gy are monitored as well as in radiotherapy where doses up to several Gray are to be measured. The major advantages of TL detectors are their small physical size and that no cables or auxiliary equipment is required during the dose assessment. TLD is considered to be a good method for point dose measurements in phantoms as well as for in vivo dosimetry on patients during radiotherapy treatment. As an integrative dosimetric technique, it can be applied to personal dosimetry and it lends itself to the determination of dose distributions due to multiple or moving radiation sources (e.g. conformal and dynamic radiotherapy, computed tomography). In addition, TL dosimeters are easy to transport, and they can be mailed. This makes them well suited for intercomparison of doses delivered in different institutions. The present article aims at describing the various applications TLD has found in medicine by taking into consideration the physics and practice of TLD measurements which have been discussed in the first part of this review. 198 refs., 4 tabs., 2 figs

  12. Segmented phantoms reconstruction for skin dosimetry

    International Nuclear Information System (INIS)

    Antunes, Paula C.G.; Siqueira, Paulo T.D.; Yoriyaz, Helio; Fonseca, Gabriel P.; Furnari, Laura; Reis, Gabriela S.

    2009-01-01

    There are several radio-sensitive skin diseases. Skin dosimetry is a difficult task to be properly performed, not only due to skin extension and small thickness, but also because it is usually submitted to high dose gradients. High-resolution medical images along with methods that simulate the interaction of radiation with matter, as the Monte Carlo radiation transport codes, have been widely used in medical physics procedures. These images provide the construction of realistic computational anatomical models, which after being coupled to these codes, retrieve reliable dosimetric assessments. However, present day regular images are unsuitable to correctly perform skin dose distribution evaluations. This inability is due to improper skin discrimination in most of current medical images, once its thickness stands below image resolution, i.e. pixel characteristic sizes are larger than skin thickness. This paper proposes a methodology of voxelized phantom reconstruction and segmentation, by subdividing their basic elements - voxels. It is done in order to better discriminate the skin by assigning more adequate value for skin thickness and its actual localization. Aiming at a more realistic skin modeling one is expected to get more accurate skin dose evaluations. This task is an important issue in many radiotherapy procedures. A particular interest lays in Total Skin Electron Therapy (TSET), which highlights the treatment of the whole body irradiation, a radiotherapy procedure under implementation in the Hospital das Clinicas da Universidade de Sao Paulo (HC-USP). (author)

  13. Australian clinical dosimetry service at ARPANSA

    International Nuclear Information System (INIS)

    McDonald, Abel; Williams, Ivan

    2010-01-01

    Full text: Earlier this year, the Australian Health Ministers' Advisory Council accepted the Federal Government's offer to fund the establishment and operation for 3 years of an Australian Clinical Dosimetry Service (ACDS). The service will be located within the Australian Radiation Protection and Nuclear Safety Agency in Yallambie, Victoria and will commence operation at the beginning of 20II. The purpose of the ACDS is to make available independent checks and auditing services to all Australian radiotherapy services. These services will range form postal audits to site visits, and include treatment dose assessments using phantoms (Level III audits). There will be a Clinical Advisory Group to oversee the development of the service, so the ACPSEM and other professional groups will playa key role in developing the ACDS. In consultation with radiotherapy facilities, the ACDS will establish an Audit Panel which will be made up of local staff to assist with on site work and minimise travel costs. The results of all measurements made by the ACDS will be confi dential: only de-identified data would be publicly reported. The service will be free to participating facilities in the first 3 years. An independent review will be conducted in the third year to determine the ongoing arrangements for the service.

  14. Dosimetry: an ARDENT topic

    CERN Multimedia

    CERN Bulletin

    2012-01-01

    The first annual ARDENT workshop took place in Vienna from 20 to 23 November. The workshop gathered together the Early-Stage Researchers (ESR) and their supervisors, plus other people involved from all the participating institutions.   “The meeting, which was organised with the local support of the Austrian Institute of Technology, was a nice opportunity for the ESRs to get together, meet each other, and present their research plans and some preliminary results of their work,” says Marco Silari, a member of CERN Radiation Protection Group and the scientist in charge of the programme. Two full days were devoted to a training course on radiation dosimetry, delivered by renowned experts. The workshop closed with a half-day visit to the MedAustron facility in Wiener Neustadt. ARDENT (Advanced Radiation Dosimetry European Network Training) is a Marie Curie ITN project funded under EU FP7 with €4 million. The project focuses on radiation dosimetry exploiting se...

  15. Dosimetry in dentistry.

    Science.gov (United States)

    Asha, M L; Chatterjee, Ingita; Patil, Preeti; Naveen, S

    2015-01-01

    The purpose of this paper was to review various dosimeters used in dentistry and the cumulative results of various studies done with various dosimeters. Several relevant PubMed indexed articles from 1999 to 2013 were electronically searched by typing "dosimeters", "dosimeters in dentistry", "properties of dosimeters", "thermoluminescent and optically stimulated dosimeters", "recent advancements in dosimetry in dentistry." The searches were limited to articles in English to prepare a concise review on dental dosimetry. Titles and abstracts were screened, and articles that fulfilled the criteria of use of dosimeters in dental applications were selected for a full-text reading. Article was divided into four groups: (1) Biological effects of radiation, (2) properties of dosimeters, (3) types of dosimeters and (4) results of various studies using different dosimeters. The present review on dosimetry based on various studies done with dosimeters revealed that, with the advent of radiographic technique the effective dose delivered is low. Therefore, selection of radiological technique plays an important role in dental dose delivery.

  16. Dosimetry in life sciences

    International Nuclear Information System (INIS)

    1975-01-01

    The uses of radiation in medicine and biology have grown in scope and diversity to make the Radiological Sciences a significant factor in both research and medical practice. Of critical importance in the applications and development of biomedical and radiological techniques is the precision with which the dose may be determined at all points of interest in the absorbing medium. This has developed as a result of efficacy of investigations in clinical radiation therapy, concern for patient safety and diagnostic accuracy in diagnostic radiology and the advent of clinical trials and research into the use of heavily ionizing radiations in biology and medicine. Since the last IAEA Symposium on Dosimetry Techniques applied to Agriculture, Industry, Biology and Medicine, held in Vienna in 1972, it has become increasingly clear that advances in the techniques and hardware of biomedical dosimetry have been rapid. It is for these reasons that this symposium was organized in a concerted effort to focus on the problems, developments and areas of further research in dosimetry in the Life Sciences. (author)

  17. Experimental IMRT breast dosimetry in a thorax phantom

    Energy Technology Data Exchange (ETDEWEB)

    Pimenta, Elsa B.; Campos, Tarcisio P.R.; Nogueira, Luciana B.; Lima, Andre C.S., E-mail: elsabpimenta@gmail.com, E-mail: tprcampos@pq.cnpq.br, E-mail: lucibn19@yahoo.com.br, E-mail: radioterapia.andre@gmail.com [Universidade Federal de Minas Gerais (UFMG), Belo Horizonte, MG (Brazil); Centro de Tratamento em Radioterapia, Betim, MG (Brazil)

    2017-11-01

    Radiation therapy (RT) is an essential therapeutic method. RT is often used as adjuvant therapy in the treatment of breast cancer. The dose-volume restrictions of the organs at risk limit the prescribed dose to the target volume and biological and clinical effects may influence the final treatment outcome. The breast RT provides large risks to the adjacent organs and consequently the recommended dosimetry to the prescribed dose volume (PTV) is 50 Gy, lower than the most prescribed dose in other treatments (70-85 Gy). Such values implies in less tumor control compared to other sites. The present research proposal aimed to measure absorbed dose in a thorax phantom with synthetic breasts provided by an Intensity-Modulate Radiation Therapy (IMRT) protocol in a RT center. On the methodology, IMRT protocol was selected following recommendations from the Radiation Therapy Oncology Group (RTOG). Radiochromic films and a thorax simulator were prepared by the Ionizing Radiation Research Group (NRI). Dosimeters were calibrated on a selected linear accelerator (LINAC). The comparison of the dosimetry from treatment planning system (TPS), Xio (Elekta) and from experimental data was performed. The spatial distribution of the breast internal dose and in the adjacent organs was depicted by the experimental data. In the film's calibration, the quadratic polynomial fit presented a satisfactory coefficient. Two-dimensional dose profiles were obtained in the breast suggesting that films can supply details and information that TPS does not provide. At the phantom's dosimetry, the internal mean doses taken at the synthetic breast presented usual values above the prescribed dose, besides overall values were within the dosimetric MSKCC criterion. The non full reproduction of the build-up region in the films had occurred due to the asymmetrical positioning of the films in the inner breast, in addition to their non constant distance from the skin. The hot regions were present may

  18. Experimental IMRT breast dosimetry in a thorax phantom

    International Nuclear Information System (INIS)

    Pimenta, Elsa B.; Campos, Tarcisio P.R.; Nogueira, Luciana B.; Lima, Andre C.S.

    2017-01-01

    Radiation therapy (RT) is an essential therapeutic method. RT is often used as adjuvant therapy in the treatment of breast cancer. The dose-volume restrictions of the organs at risk limit the prescribed dose to the target volume and biological and clinical effects may influence the final treatment outcome. The breast RT provides large risks to the adjacent organs and consequently the recommended dosimetry to the prescribed dose volume (PTV) is 50 Gy, lower than the most prescribed dose in other treatments (70-85 Gy). Such values implies in less tumor control compared to other sites. The present research proposal aimed to measure absorbed dose in a thorax phantom with synthetic breasts provided by an Intensity-Modulate Radiation Therapy (IMRT) protocol in a RT center. On the methodology, IMRT protocol was selected following recommendations from the Radiation Therapy Oncology Group (RTOG). Radiochromic films and a thorax simulator were prepared by the Ionizing Radiation Research Group (NRI). Dosimeters were calibrated on a selected linear accelerator (LINAC). The comparison of the dosimetry from treatment planning system (TPS), Xio (Elekta) and from experimental data was performed. The spatial distribution of the breast internal dose and in the adjacent organs was depicted by the experimental data. In the film's calibration, the quadratic polynomial fit presented a satisfactory coefficient. Two-dimensional dose profiles were obtained in the breast suggesting that films can supply details and information that TPS does not provide. At the phantom's dosimetry, the internal mean doses taken at the synthetic breast presented usual values above the prescribed dose, besides overall values were within the dosimetric MSKCC criterion. The non full reproduction of the build-up region in the films had occurred due to the asymmetrical positioning of the films in the inner breast, in addition to their non constant distance from the skin. The hot regions were present may

  19. The use of Monte Carlo codes in internal dosimetry; Utilisation des codes de Monte Carlo en dosimetrie interne

    Energy Technology Data Exchange (ETDEWEB)

    Ricard, M.; Coulot, J. [Institut Gustave-Roussy, Service de Physique, 94 - Villejuif (France)

    2003-07-01

    Internal dosimetry concerns the radiation sources inside human body. It contributes to determine the energy depositions in a living organism following the accidental or medical irradiation. In the case of an accidental irradiation, the aim is to evaluate the risk estimation; in the case of a medical use the dosimetry data are used in a radiation protection purpose. In any case, it is necessary to have references methods in order to know the dose absorbed bound to the radioactive product incorporation. Three levels have to be considered: the organ level in radiation protection, the cellular and tissue levels for application in radiotherapy. The analytical methods become rapidly difficult to use so the Monte Carlo methods give now a correct statistical precision. The advantages of this way of doing are developed in this article. (N.C.)

  20. Automatization in radiotherapy

    International Nuclear Information System (INIS)

    Schraub, S.; Dutou, L.; Bernard, D.; Koechlin, M.; Beer-Gabel, J.

    1978-01-01

    Data-processing in external radiotherapy has to be adapted to each local situation, taking into account the patients to be treated, the irradiation equipment, the data-processing centers available locally, regionally, and nationally, and the rentability of the data-processing system required. It should be recalled that most dosimetric methods used today can be treated manually, and the question of rentability has to be kept in mind when deciding to buy a data-processing system. The radiotherapist should, therefore, prepare a list of costs for each situation, and verify the validity of each programme proposed by the supplier. It is difficult to make a definite choice between the presently available systems. The radiotherapist has to choose in relation to his activity, his availability and the systems available to him. It can sometimes be more advantageous to have a terminal linked to a large computer, rather than to readapt a series of programmes for a data-processing system available locally: many such solutions, though original, cannot be 'exported'. It should be recalled that a large number of dosimetries can be obtained manually, and on the rare occasions when the aid of a computer is essential, the assistance of better equipped neighbouring centers can be obtained. The decision as to whether a data-processing system needs to be acquired has to take all these imperatives into account [fr

  1. Dose profile analysis of small fields in intensity modulated radiotherapy

    International Nuclear Information System (INIS)

    Medel B, E.; Tejeda M, G.; Romero S, K.

    2015-10-01

    Full text: Small field dosimetry is getting a very important worldwide task nowadays. The use of fields of few centimeters is more common with the introduction of sophisticated techniques of radiation therapy, as Intensity Modulated Radiotherapy (IMRT). In our country the implementation of such techniques is just getting started and whit it the need of baseline data acquisition. The dosimetry under small field conditions represents a challenge for the physicists community. In this work, a dose profile analysis was done, using various types of dosimeters for further comparisons. This analysis includes the study of quality parameters as flatness, symmetry, penumbra, and other in-axis measurements. (Author)

  2. Proofs of acceptance of ionization cameras for use in radiotherapy

    International Nuclear Information System (INIS)

    Davila, Hernan Olaya; Flores, Guillermo

    2013-01-01

    Shows the main technical tests released in the Secondary Standard Dosimetry Laboratory (SSDL) of one cylindrical ionization chamber and another plane parallel ionization chamber similar to used in radiotherapy services in Colombia to the radiation dose control that is delivered to the patient to the cancer treatment. The previous test of one calibration see in this work are: correction for recombination losses, polarity dependence, stabilization time, total dose dependence, atmospheric communication, stability check, leakage current and physical integrity. Calculates the acceptability values in the SSDL to be account as reference for the dosimetry systems that are carry in calibration process. (author)

  3. Dose profile analysis of small fields in intensity modulated radiotherapy

    Energy Technology Data Exchange (ETDEWEB)

    Medel B, E. [IMSS, Centro Medico Nacional Manuel Avila Camacho, Calle 2 Nte. 2004, Barrio de San Francisco, 72090 Puebla, Pue. (Mexico); Tejeda M, G.; Romero S, K., E-mail: romsakaren@gmail.com [Benemerita Universidad Autonoma de Puebla, Facultad de Ciencias Fisico Matematicas, Av. San Claudio y 18 Sur, Ciudad Universitaria, 72570 Puebla, Pue.(Mexico)

    2015-10-15

    Full text: Small field dosimetry is getting a very important worldwide task nowadays. The use of fields of few centimeters is more common with the introduction of sophisticated techniques of radiation therapy, as Intensity Modulated Radiotherapy (IMRT). In our country the implementation of such techniques is just getting started and whit it the need of baseline data acquisition. The dosimetry under small field conditions represents a challenge for the physicists community. In this work, a dose profile analysis was done, using various types of dosimeters for further comparisons. This analysis includes the study of quality parameters as flatness, symmetry, penumbra, and other in-axis measurements. (Author)

  4. Recent developments in detectors/phantoms for dosimetry, X-ray quality assurance and imaging

    International Nuclear Information System (INIS)

    Sankaran, A.

    2009-01-01

    During the past years, many new developments have taken place in detectors/phantoms for high energy photon and electron dosimetry (for radiotherapy), protection monitoring, X-ray quality assurance and X-ray imaging (for radiodiagnosis). A variety of detectors and systems, quality assurance (QA) gadgets and special phantoms have been developed for diverse applications. This paper discusses the important developments with some of which the author was actively associated in the past. For dosimetry and QA of 60 Co and high energy X-ray units, state-of-the-art radiation field analyzers, matrix ion chambers, MOSFET devices and Gafchromic films are described. OSL detectors find wide use in radiotherapy dosimetry and provide a good alternative for personnel monitoring. New systems introduced for QA/dosimetry of X-ray units and CT scanners include: multi-function instruments for simultaneous measurement of kVp, dose, time, X-ray waveform and HVT on diagnostic X-ray units; pencil chamber with head and body phantoms for CTDI check on CT scanners. Examples of phantoms used for dosimetry and imaging are given. Advancements in the field of diagnostic X-ray imaging (with applications in portal imaging/dosimetry of megavoltage X-ray units) have led to emergence of: film-replacement systems employing CCD-scintillator arrays, computed radiography (CR) using storage phosphor plate; digital radiography (DR), using a pixel-matrix of amorphous selenium, or amorphous silicon diode coupled to scintillator. All these provide (a) in radiotherapy, accurate dose delivery to tumour, saving the surrounding tissues and (b) in radiodiagnosis, superior image quality with low patient exposure. Lastly, iPODs and flash drives are utilized for storage of gigabyte-size images encountered in medical and allied fields. Although oriented towards medical applications, some of these have been of great utility in other fields, such as industrial radiography as well as a host of other research areas. (author)

  5. TLD audit in radiotherapy in the Czech Republic

    International Nuclear Information System (INIS)

    Kroutilikova, D.; Zackova, H.; Judas, L.

    1998-01-01

    National Radiation Protection Institute in Prague organizes the TLD audit. The aim of the TLD postal audit is to provide control of the clinical dosimetry in the Czech Republic for purposes of state supervision in radiotherapy, to investigate and to reduce uncertainties involved in the measurements of absorbed dose and to improve consistency in dose determination in the regional radiotherapy centers. TLD audit covers absorbed dose measurements under reference conditions for 60 Co and 137 Cs beams, high-energy X-ray and electron beams of of linear accelerators and betatrons. The thermo-luminescence dosemeters are sent regularly to all radiotherapy centers. Absorbed dose measures by the TLD is compared to absorbed dose stated by radiotherapy center. Encapsulated LiF:Mg, Ti powder is used for the measurement. Deviation of 3% between stated and TLD measured dose is considered for photons and ±5% for electron beams. First TLD audit was started in 1997. A total of 135 beams was checked. There were found seven major deviations (more than ±6%), which were very carefully investigated. Medical Physicists from these departments reported a set-up mistake. However, at most of those hospitals with major deviations, an in situ audit in details was made soon after TLD audit. There were found discrepancies of clinical dosimetry but also bad technical state of some of the irradiation units. In 1998, second course TLD audit was started. No major deviation was found. Regular TLD audit seems to be a good way to eliminate big mistakes in the basic clinical dosimetry. Repeated audit in the regional radiotherapy centers that had major deviation during the first audit exhibited improvement of their dosimetry. It is intended to broaden the method and to control also beam parameters by means of a multi-purpose phantom. (authors)

  6. EPID based in vivo dosimetry system: clinical experience and results.

    Science.gov (United States)

    Celi, Sofia; Costa, Emilie; Wessels, Claas; Mazal, Alejandro; Fourquet, Alain; Francois, Pascal

    2016-05-08

    Mandatory in several countries, in vivo dosimetry has been recognized as one of the next milestones in radiation oncology. Our department has implemented clinically an EPID based in vivo dosimetry system, EPIgray, by DOSISOFT S.A., since 2006. An analysis of the measurements per linac and energy over a two-year period was performed, which included a more detailed examination per technique and treat-ment site over a six-month period. A comparison of the treatment planning system doses and the doses estimated by EPIgray shows a mean of the differences of 1.9% (± 5.2%) for the two-year period. The 3D conformal treatment plans had a mean dose difference of 2.0% (± 4.9%), while for intensity-modulated radiotherapy and volumetric-modulated arc therapy treatments the mean dose difference was -3.0 (± 5.3%) and -2.5 (± 5.2%), respectively. In addition, root cause analyses were conducted on the in vivo dosimetry measurements of two breast cancer treatment techniques, as well as prostate treatments with intensity-modulated radiotherapy and volumetric-modulated arc therapy. During the breast study, the dose differences of breast treatments in supine position were correlated to patient setup and EPID positioning errors. Based on these observations, an automatic image shift correc-tion algorithm is developed by DOSIsoft S.A. The prostate study revealed that beams and arcs with out-of-tolerance in vivo dosimetry results tend to have more complex modulation and a lower exposure of the points of interest. The statistical studies indicate that in vivo dosimetry with EPIgray has been successfully imple-mented for classical and complex techniques in clinical routine at our institution. The additional breast and prostate studies exhibit the prospects of EPIgray as an easy supplementary quality assurance tool. The validation, the automatization, and the reduction of false-positive results represent an important step toward adaptive radiotherapy with EPIgray.

  7. Reconstruction of voxel phantoms for skin dosimetry

    International Nuclear Information System (INIS)

    Antunes, Paula Cristina Guimaraes

    2010-01-01

    Radiotherapy is a therapeutic modality that utilizes ionizing radiation for the destruction of neoplastic human cells. One of the requirements for this treatment methodology success lays on the appropriate use of planning systems, which performs, among other information, the patient's dose distribution estimate. Nowadays, transport codes have been providing huge subsidies to these planning systems, once it enables specific and accurate patient organ and tissue dosimetry. The model utilized by these codes to describe the human anatomy in a realistic way is known as voxel phantoms, which are represented by discrete volume elements (voxels) directly associated to tomographic data. Nowadays, voxel phantoms doable of being inserted and processed by the transport code MCNP (Monte Carlo N-Particle) presents a 3-4 mm image resolution; however, such resolution limits some thin body structure discrimination, such as skin. In this context, this work proposes a calculus routine that discriminates this region with thickness and localization in the voxel phantoms similar to the real, leading to an accurate dosimetric skin dose assessment by the MCNP code. Moreover, this methodology consists in manipulating the voxel phantoms volume elements by segmenting and subdividing it in different skin thickness. In addition to validate the skin dose calculated data, a set of experimental evaluations with thermoluminescent dosimeters were performed in an anthropomorphic phantom. Due to significant differences observed on the dose distribution of several skin representations, it was found that is important to discriminate the skin thickness similar to the real. The presented methodology is useful to obtain an accurate skin dosimetric evaluation for several radiotherapy procedures, with particular interest on the electron beam radiotherapy, in which highlights the whole body irradiation therapy (TSET), a procedure under implementation at the Hospital das Clinicas da Faculdade de Medicina da

  8. Experience in the treatment of IMRT in prostate cancer. Planning, dosimetry and quality control

    International Nuclear Information System (INIS)

    Gomez Barrado, A.; Garcia Vicente, F.; Fernandez Bedoya, V.; Bermudez Luna, R.; Perez Gonzalez, L.; Torres Escobar, J. J.

    2011-01-01

    The aim of this study is to review the treatment of prostate cancer at our center. A description of the entire procedure, involving clinical dosimetry, and procedures for verification of treatment, including physical dosimetry and parallel computing system MSure (Standard Imaging, Inc., Middleton) as part of these procedures. This system is based on the model published by trifuente Yang et al. (Yang et al. 2002) for testing treatments regarding the number of monitor unit (MU) given. In addition, this software has a module for the testing of treatments for intensity modulated radiotherapy (IMRT), which will be analyzed in this study.

  9. Registration and planning of radiotherapy and proton therapy treatment

    International Nuclear Information System (INIS)

    Bausse, Jerome

    2010-01-01

    Within the frame of an update and renewal project, the Orsay Proton Therapy Centre of the Curie Institute (IPCO) renews its software used for the treatment of patients by proton therapy, a radiotherapy technique which uses proton beams. High energies used in these treatments and the precision provided by proton particle characteristics require a more precise patient positioning than conventional radiotherapy: proton therapy requires a precision of about a millimetre. Thus, markers are placed on the skull which are generally well accepted by patients, but are a problem in the case of paediatric treatment, notably for the youngest children whose skull is still growing. The first objective of this research is thus to use only intrinsic information from X-ray images used when positioning the patient. A second objective is to make the new software (TPS Isogray) perfectly compatible with IPCO requirements by maintaining the strengths of the previous TPS (Treatment Planning System) and being prepared to the implementation of a new installation. After a presentation of the context and state of the art in radiotherapy and patient positioning, the author proposes an overview of 2D registration methods, presents a new method for 2x2D registration, and addresses the problem of 3D registration. Then, after a presentation of proton therapy, the author addresses different specific issues and aspects: the compensator (simulation, calculation, and tests), dose calculation, the 'Pencil-Beam' algorithm, tests, and introduced improvements [fr

  10. Magnetic resonance imaging for precise radiotherapy of small laboratory animals

    Energy Technology Data Exchange (ETDEWEB)

    Frenzel, Thorsten [Universitaetsklinikum Hamburg-Eppendorf, Hamburg (Germany). Bereich Strahlentherapie; Universitaetsklinikum Hamburg-Eppendorf, Hamburg (Germany). Inst. fuer Anatomie und Experimentelle Morphologie; Kaul, Michael Gerhard; Ernst, Thomas Michael; Salamon, Johannes [Universitaetsklinikum Hamburg-Eppendorf, Hamburg (Germany). Klinik und Poliklinik fuer Diagnostische und Interventionelle Radiologie; Jaeckel, Maria [Universitaetsklinikum Hamburg-Eppendorf, Hamburg (Germany). Klinik und Poliklinik fuer Strahlentherapie und Radioonkologie; Schumacher, Udo [Universitaetsklinikum Hamburg-Eppendorf, Hamburg (Germany). Inst. fuer Anatomie und Experimentelle Morphologie; Kruell, Andreas [Universitaetsklinikum Hamburg-Eppendorf, Hamburg (Germany). Bereich Strahlentherapie

    2017-05-01

    Radiotherapy of small laboratory animals (SLA) is often not as precisely applied as in humans. Here we describe the use of a dedicated SLA magnetic resonance imaging (MRI) scanner for precise tumor volumetry, radiotherapy treatment planning, and diagnostic imaging in order to make the experiments more accurate. Different human cancer cells were injected at the lower trunk of pfp/rag2 and SCID mice to allow for local tumor growth. Data from cross sectional MRI scans were transferred to a clinical treatment planning system (TPS) for humans. Manual palpation of the tumor size was compared with calculated tumor size of the TPS and with tumor weight at necropsy. As a feasibility study MRI based treatment plans were calculated for a clinical 6 MV linear accelerator using a micro multileaf collimator (μMLC). In addition, diagnostic MRI scans were used to investigate animals which did clinical poorly during the study. MRI is superior in precise tumor volume definition whereas manual palpation underestimates their size. Cross sectional MRI allow for treatment planning so that conformal irradiation of mice with a clinical linear accelerator using a μMLC is in principle feasible. Several internal pathologies were detected during the experiment using the dedicated scanner. MRI is a key technology for precise radiotherapy of SLA. The scanning protocols provided are suited for tumor volumetry, treatment planning, and diagnostic imaging.

  11. [Evaluation of transit in vivo dosimetry using portal imaging and comparison with measurements using diodes].

    Science.gov (United States)

    Royer, P; Marchesi, V; Rousseau, V; Buchheit, I; Wolf, D; Peiffert, D; Noël, A

    2014-06-01

    In vivo dosimetry transit using portal imaging is a promising approach for quality assurance in radiotherapy. A comparative evaluation was conducted between a commercial solution, EPIgray(®) and an in vivo dosimetry control reference using semiconductors diodes. The performance of the two in vivo dosimetry methods was assessed. The primary endpoint was the dose deviation between the reconstructed dose at the prescription point and the measured dose using the ionization chamber in phantoms or the calculated predictive dose by the treatment planning system with patients. The deviation threshold was set to ±5%. In total, 107 patients were prospectively included and treated with 3D-conformal radiotherapy (3D-CRT) or intensity-modulated radiotherapy (IMRT) techniques for tumours of the brain, chest and head and neck. The dosimetric accuracy of EPIgray(®) in phantom were comparable to diodes in terms of repeatability (0.11%), reproducibility (0.29-0.51%) with a mean dose deviation of 0.17% (SD: 1.11). The rates of radiotherapy sessions out of the tolerance for the brain (3D-CRT and IMRT), thorax (3D-CRT) and the head and neck (IMRT) were respectively 0%, 9.6% and 5.3% with a mean dose deviation ranging between 0.49% and 1.53%. The mean of dose deviation between three consecutive sessions with EPIgray(®) validates 99.1% of treatments. The performance of EPIgray(®) in in vivo dosimetry is consistent with the recommendations of the European Society for Radiotherapy and Oncology (ESTRO) and equivalent to semiconductor diodes for 3D-CRT. It also allows adequate control for IMRT, which is technically difficult to perform with the diodes. Copyright © 2014 Société française de radiothérapie oncologique (SFRO). Published by Elsevier SAS. All rights reserved.

  12. Dosimetry Studies of a Special Applicator for Post Hysterectomy Brachytherapy

    International Nuclear Information System (INIS)

    Schwob, N.; Shani, G.; Orion, I.

    2004-01-01

    The treatment of uterine cancer can include surgery, external beam radiotherapy and brachytherapy. The brachytherapy of the vagina stump is usually performed by inserting a radioactive source into a one channel cylindrical applicator. The resulting isodoses map from such treatment contains elliptical lines, while the target region is quite flat. A new eight-channel applicator has been developed at Hadassah University Hospital in order to obtain a flatter isodoses map (Figure 1). An 192 Ir source is loaded from the Nucletron microSelectron PDR afterloading system, step by step, at pre-selected dwell points in every channel, with pre-calculated irradiation dwell time. The particular irradiation program for every patient, the dose distribution and the isodoses were calculated using a treatment planning system (TPS) and the plan had been optimized [1]. In routine work, this is the only practical way to find the dose distribution obtained during the treatment

  13. Personal Dosimetry in UHC Sestre Milosrdnice: 10-Years Review

    International Nuclear Information System (INIS)

    Bokulic, T.; Budanec, M; Gregov, M.; Kusic, Z.; Mlinaric, M.; Mrcela, I.; Suric Mihic, M.

    2013-01-01

    Personal dose monitoring in UHC 'Sestre milosrdnice' is regulary performed for about 300 exposed workers involved in a variety of tasks with different sources of ionizing radiation. Exposed workers are required to wear personal dosimeters which are read on monthly basis and dose records are kept in the hospital. In this paper an overview of personal dosimetry data from year 2003 till 2013 is presented. Film dosimeters were used for personal dosimetry untill 2010 when the thermoluminescent (TL) dosimetry was introduced. Dosimeters are calibrated to measure personal dose equivalent H p (10). Received doses are analyzed for workers in the field of nuclear medicine, radiotherapy (external beam and brachytherapy), general diagnostic radiology and interventional radiology. Analysis of received doses in the whole period resulted with an average individual dose in nuclear medicine of 0.6 mSv/y, which decreased to 0.21 mSv/y in the last three years, caused by more precise dosimetric methods with TL dosimetry and improved conditions of radiation protection. In the same three-year period, in interventional radiology doses were 0.32 mSv/y, compared to 0.29 mSv/y obtained for a previous seven years. This was expected due to the escalation in a number of interventions and new installed equipment. There was no such difference in diagnostic radiology doses, showing that film dosimetry is suitable for x ray energies. Analysis of all the readings showed a significant influence of measurement procedures on personal dosimeter dose and also the importance of continuous monitoring of the dose records in order to improve the conditions of radiation protection and achieving the ALARA goal.(author)

  14. Internal dosimetry for occupationally exposed personnel in nuclear medicine

    International Nuclear Information System (INIS)

    Garcia, M.T.; Alfaro, L.M.M.; Angeles, C.A.

    2013-01-01

    Internal dosimetry plays an important role in nuclear medicine dosimetry control of personnel occupationally exposed, and that in recent years there has been a large increase in the use of radionuclides both in medical diagnosis as radiotherapy. But currently, in Mexico and in many parts of the world, this internal dosimetry control is not performed. The Instituto Nacional de lnvestigaciones Nucleares de Mexico (ININ) together with the Centro Oncologico de Toluca (ISEMMYM) have developed a simple and feasible methodology for monitoring of personnel working in these facilities. It was aimed to carry out the dosimetry of the personnel, due to the incorporation of I-131, using the spectrometric devices that the hospital has, a gamma camera. The first step in this methodology was to make a thyroid phantom to meet the specifications of the ninth ANSI. This phantom is compared under controlled conditions with RMC- II phantom used for system calibration of the ININ internal dosimetry (ACCUSCAN - Ll), and with another phantom developed in Brazil with ANSI specifications, in order to determine the variations in measurements due to the density of the material of each of the phantoms and adjust to the system ACCUSCAN, already certificate. Furthermore, necessary counts were performed with the gamma camera of the phantom developed at ININ, with a standard source of 133 Ba which simulates the energy of 131 I. With these data, were determined the counting efficiencies for a distance of 15 to 20 cm between the surface of the phantom and the the plate of the detectors. Another important aspect was to determine the lower limit of detection (LLD). In this paper we present the results obtained from the detectors calibration of the gamma camera of the hospital.

  15. New methodologies of biological dosimetry applied to human protection

    International Nuclear Information System (INIS)

    Catena, C.; Parasacchi, P.; Conti, D.; Righi, E.

    1995-04-01

    Biological dosimetry is a diagnostic methodology for the measurement of the individual dose absorbed in the case of accidental overexposition to ionizing radiation. It is demonstrated how in vitro radiobiological and chemobiological studies using cytogenetic methods (count of chromosomal aberrations and micronuclei) on human lymphocytes from healthy subjects and individuals undergoing radiotherapy or chemotherapy, as well as on lymphocytes of mammals other than man (comparative cytogenetics), can help to increase the basic radiobiological and chemobiological scientific information. Such information gives a valid contribution to understanding of the action of ionizing radiation or of pharmaceuticals on cells and, in return, can be of value to human radioprotection and chemoprotection. Cytogenetic studies can be summerized as follows: a) biodosimetry (estimate of dose received after accidental events); b) individual radiosensitivity (level of individual response); c) clinical radiobiology and chemobiology (individual response to radiopharmaceuticals, to radiotherapy and to chemopharmaceuticals); d) comparative radiobiology (cytogenetic studies on species other than man); e) animal model in the environmental surveillance

  16. Palliative Radiotherapy

    International Nuclear Information System (INIS)

    Salinas, J.

    2003-01-01

    Palliative care does not attempt to prolong survival but to the achieve the highest quality of life both for the patient and their family covering their physical, psychological, social and spiritual needs. Radiotherapy (RT), one of the most important therapeutic modalities, has a great significance in palliative medicine for cancer since it attempts to reduce as much as possible the acute reaction associated with the treatment for the patient. (Author)

  17. Relocation of Dosimetry Service

    CERN Document Server

    2007-01-01

    The Dosimetry Service is moving from Building 24 to Building 55 and will therefore be closed on Friday, March 30. From Monday, April 2 onwards you will find us in building 55/1-001. Please note that during that day we might still have some problems with the internet connections and cannot fully guarantee normal service procedures. The service's opening hours and telephone number will not change as a result of the move 8.30 - 12.00, afternoons closed Tel. 72155

  18. Individual dosimetry and calibration

    International Nuclear Information System (INIS)

    Hoefert, M.; Nielsen, M.

    1996-01-01

    In 1995 both the Individual Dosimetry and Calibration Sections worked under the condition of a status quo and concentrated fully on the routine part of their work. Nevertheless, the machine for printing the bar code which will be glued onto the film holder and hence identify the people when entering into high radiation areas was put into operation and most of the holders were equipped with the new identification. As far as the Calibration Section is concerned the project of the new source control system that is realized by the Technical Support Section was somewhat accelerated

  19. Heavy-ion dosimetry

    International Nuclear Information System (INIS)

    Schimmerling, W.

    1980-03-01

    This lecture deals with some of the more important physical characteristics of relativistic heavy ions and their measurement, with beam delivery and beam monitoring, and with conventional radiation dosimetry as used in the operation of the BEVALAC biomedical facility for high energy heavy ions (Lyman and Howard, 1977; BEVALAC, 1977). Even so, many fundamental aspects of the interaction of relativistic heavy ions with matter, including important atomic physics and radiation chemical considerations, are not discussed beyond the reminder that such additional understanding is required before an adequte perspective of the problem can be attained

  20. Fast neutron dosimetry

    International Nuclear Information System (INIS)

    DeLuca, P.M. Jr.; Pearson, D.W.

    1992-01-01

    This progress report concentrates on two major areas of dosimetry research: measurement of fast neutron kerma factors for several elements for monochromatic and white spectrum neutron fields and determination of the response of thermoluminescent phosphors to various ultra-soft X-ray energies and beta-rays. Dr. Zhixin Zhou from the Shanghai Institute of Radiation Medicine, People's Republic of China brought with him special expertise in the fabrication and use of ultra-thin TLD materials. Such materials are not available in the USA. The rather unique properties of these materials were investigated during this grant period

  1. INDIVIDUAL DOSIMETRY SERVICE

    CERN Document Server

    2000-01-01

    Personnel in the distribution groups Aleph, Delphi, L3, Opal who also work for other experiments than at LEP, should contact their dispatchers to explain their activities for the future, after LEP dismantling in order to be maintained on the regular distribution list at Individual Dosimetry ServiceWe inform all staffs and users under regular dosimetric control that the dosimeters for the monitoring period JULY/AUGUST are available from their usual dispatchers.Please have your films changed before the 10th of July.The colour of the dosimeter valid in JULY/AUGUST is PINK.

  2. Rapid electro-optical (EO) TPS development in a military environment

    Science.gov (United States)

    McKechnie, James; Irwin, Alan; Gauntner, Thomas

    2012-06-01

    Santa Barbara Infrared, Inc. has deployed IRWindows as an Electro-Optical test development and execution environment for military Test Program Sets (TPS). Advantages of TPS development for EO systems in the IRWindows environment are seen compared to the TPS development in ATLAS. The advantages of the IRWindows environment are: 1. Faster learning curve (graphical user interface is easier than test line interface) 2. Faster TPS development time (real time changes and asset control interface allows for faster development) 3. Asset control panel allows user to control assets real time and monitor all asset functions during development 4. Unit Under Test (UUT) image viewer allows user to set test parameters like Region of Interest more easily and more precisely 5. Continuous mode tests (like MTF allows user to real time adjustments) 6. Open architecture for test modifications This paper will outline the details of how these advantages are utilized and how not only development time is decreased but also how test execution time can be minimized making traditionally long TPS run times on EO systems more efficient.

  3. Dosimetry of internal emitting: principles and perspectives of the MIRD technology

    International Nuclear Information System (INIS)

    Ferro F, G.

    1999-01-01

    The development of the radiopharmaceutical technology have multiplied the number of radioisotopes with applications in therapeutical nuclear medicine so known as Directed radiotherapy. Assuming the radiation is capable to produce noxious effects in the biological systems, it is important to evaluate appropriately the risks and benefits of the administration of radioactive agents in the patient. The outstanding parameter in this evaluation is the absorbed dose, which is product of the radiation emitted by a radionuclide that is localized or distributed to the interior of the human body in study and whose its estimation helps to predict the efficacy of the treatment. The scheme generalized of MIRD, it was formulated from thirty years ago for evaluating the interior dosimetry at level of organs.The finality of this work is to show the basic principles of the MIRD methodology and its perspectives using innovator tools as the dosimetry for dynamic masses, in particular the personnel dosimetry for the organs of each patient, the dosimetry for the small structures inside the organs (sub organic dosimetry), the distributions of doses in three dimensions (S voxel), the dosimetry at cellular level and the quantitative acquisition of pharmaceutical data. (Author)

  4. Graded Density Carbon Bonded Carbon Fiber (CBCF) Preforms for Lightweight Ablative Thermal Protection Systems (TPS), Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — FMI currently manufactures Phenolic Impregnated Carbon Ablator (PICA) material for Thermal Protection Systems (TPS) systems, such as the Stardust Sample Return...

  5. STRATEGI PENENTUAN LOKASI DAN KEBUTUHAN LAHAN TPS (TEMPAT PENAMPUNGAN SEMENTARA SAMPAH BERDASARKAN FUNGSI KAWASAN DI KOTA DENPASAR

    Directory of Open Access Journals (Sweden)

    Ismid Achmad

    2015-08-01

    Full Text Available The percentage of solid waste services Denpasar City in 2013 reached 51,8 percent, the limited number and capacity TPS in Denpasar not meet the needs of waste management services in denpasar. The study was to examine the relevant strategies appropriate to the criteria and requirements related to the determination of the location of TPS and the land need. The position of the study is Part Of The City (BWK Central in Denpasar. Analysis of technical aspects will evaluation garbage production in order to know the ideal needs of TPS, the evaluation of TPS placement based on the function of the area and the land needed. Environmental aspect will analyze the environmental risk due to the presence of a TPS. Analysis of public opinion and the behavior of people will use a questionnaire in the collection of data to be analyzed with qualitative methods as a consideration in determining the location and design of a TPS. Institutional aspect will be evaluated about the understanding DKP (Office of Cleaning and Gardening Services employees of the City of Denpasar in the management of garbage, especially in the TPS. As for determining the direction and strategy of the management of garbage SWOT analysis was used.Based on the analysis, the need for the addition of TPS to improve the capacity of TPS, the shape of TPS had comply standard of SNI and environmental safety factor. Additions and changes in the shape of TPS also effect land requirement, the total area of land that must be reserved for TPS is 0,40 hectares. Determining the location of TPS is based on the need of the type of TPS over the spatial pattern. Analysis of public opinion on the determination of the location of TPS, it is obtained that the distance of a TPS with the source must be relatively close and the land use is a vacant land. It is also suggested optimizing the role of the DKP of Denpasar by increasing socialization and community development programs in waste management.

  6. Use of a commercial spreadsheet for quality control in radiotherapy

    International Nuclear Information System (INIS)

    Sales, D.A.G.; Batista, D.V.S.

    2001-01-01

    This work presents the results obtained from elaboration of a spreadsheet to quality control of physical and clinical dosimetry of a radiotherapy service. It was developed using the resources of a commercial software, in the way to behave an independent verification of manual calculation and therapy planning system calculation to routine procedures of radiotherapy service of Instituto Nacional de Cancer. Its validation was made with the reference of current manual calculation proposed at literature and with the results of therapy planning system for test cases. (author)

  7. Dosimetry of industrial sources

    International Nuclear Information System (INIS)

    Vega C, H.R.; Rodriguez J, R.; Manzanares A, E.; Hernandez V, R.; Ramirez G, J.; Rivera M, T.

    2007-01-01

    The gamma rays are produced during the disintegration of the atomic nuclei, its high energy allows them to cross thick materials. The capacity to attenuate a photons beam allows to determine the density, in line, of industrial interest materials as the mining. By means of two active dosemeters and a TLDs group (passive dosimetry) the dose rates of two sources of Cs-137 used for determining in line the density of mining materials were determined. With the dosemeters the dose levels in diverse points inside the grave that it harbors the sources and by means of calculations the isodoses curves were determined. In the phase of calculations was supposed that both sources were punctual and the isodose curves were calculated for two situations: naked sources and in their Pb packings. The dosimetry was carried out around two sources of 137 Cs. The measured values allowed to develop a calculation procedure to obtain the isodoses curves in the grave where the sources are installed. (Author)

  8. Reference dosimetry data and modeling challenges for Elekta accelerators based on IROC-Houston site visit data.

    Science.gov (United States)

    Kerns, James R; Followill, David S; Lowenstein, Jessica; Molineu, Andrea; Alvarez, Paola; Taylor, Paige A; Kry, Stephen F

    2018-03-14

    Reference dosimetry data can provide an independent second check of acquired values when commissioning or validating a treatment planning system (TPS). The Imaging and Radiation Oncology Core at Houston (IROC-Houston) has measured numerous linear accelerators throughout its existence. The results of those measurements are given here, comparing accelerators and the agreement of measurement versus institutional TPS calculations. Data from IROC-Houston on-site reviews from 2000 through 2014 were analyzed for all Elekta accelerators, approximately 50. For each, consistent point dose measurements were conducted for several basic parameters in a water phantom, including percentage depth dose, output factors, small-field output factors, off-axis factors, and wedge factors. The results were compared by accelerator type independently for 6, 10, 15, and 18 MV. Distributions of the measurements for each parameter are given, providing the mean and standard deviation. Each accelerator's measurements were also compared to its corresponding TPS calculation from the institution to determine the level of agreement, as well as determining which dosimetric parameters were most often in error. Accelerators were grouped by head type and reference dosimetric values were compiled. No class of linac had better overall agreement with its TPS, but percentage depth dose and output factors commonly agreed well, while small-field output factors, off-axis factors, and wedge factors often disagreed substantially from their TPS calculations. Reference data has been collected and analyzed for numerous Elekta linacs, which provide an independent way for a physicist to double-check their own measurements to prevent gross treatment errors. In addition, treatment planning parameters more often in error have been highlighted, providing practical caution for physicists commissioning treatment planning systems for Elekta linacs. © 2018 American Association of Physicists in Medicine.

  9. Development of Solid State Thermal Sensors for Aeroshell TPS Flight Applications

    Science.gov (United States)

    Martinez, Ed; Oishi, Tomo; Gorbonov, Sergey

    2005-01-01

    In-situ Thermal Protection System (TPS) sensors are required to provide verification by traceability of TPS performance and sizing tools. Traceability will lead to higher fidelity design tools, which in turn will lead to lower design safety margins, and decreased heatshield mass. Decreasing TPS mass will enable certain missions that are not otherwise feasible, and directly increase science payload. NASA Ames is currently developing two flight measurements as essential to advancing the state of TPS traceability for material modeling and aerothermal simulation: heat flux and surface recession (for ablators). The heat flux gage is applicable to both ablators and non-ablators and is therefore the more generalized sensor concept of the two with wider applicability to mission scenar