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Sample records for cf-252 brachytherapy source

  1. Effect of tissue inhomogeneities on dose distributions from Cf-252 brachytherapy source.

    Science.gov (United States)

    Ghassoun, J

    2013-01-01

    The Monte Carlo method was used to determine the effect of tissue inhomogeneities on dose distribution from a Cf-252 brachytherapy source. Neutron and gamma-ray fluences, energy spectra and dose rate distributions were determined in both homogenous and inhomogeneous phantoms. Simulations were performed using the MCNP5 code. Obtained results were compared with experimentally measured values published in literature. Results showed a significant change in neutron dose rate distributions in presence of heterogeneities. However, their effect on gamma rays dose distribution is minimal. PMID:23069196

  2. Importance of the neutrons kerma coefficient in the planning of Brachytherapy treatments with Cf-252 sources

    International Nuclear Information System (INIS)

    The Cf-252 is a fast neutrons emitting radioisotope by spontaneous fission that can be used as sealed source in medicine applications, industry and research. Commercially its offer sources of different sizes, compact and with a fast neutrons emission of the order of 106 n/s-μg and an energy spectra that presents respectively maxim and average energy in 2.1 MeV and 0.7 MeV. In medicine new applications are being developed for the treatment of patient with hypoxic and voluminous tumors, where the therapy with photons has not given positive results, as well as for the protocols of therapy treatment by boron neutron capture, where very small sources of Cf-252 will be used with the interstitial brachytherapy technique of high and low dose rate. In this work an analysis of how the small differences that exist in the elementary composition of 4 wicked tumors, 4 ICRU healthy tissues and 3 substitute materials of ICRU tissue used in dosimetry are presented, its generate changes in the neutrons kerma coefficient in function of the energy and consequently in the absorbed dose in the interval of 11 eV to 29 MeV. These differences can produce maximum variations of the neutron kerma coefficients ratio for En > 1 keV of the one: 15% tumor/ICRU guest healthy tissue, 12% ICRU tumor/muscle, 12% ICRU healthy tissues ICRU/ICRU muscle, 22% substitutes tissue/tumor and 22% ICRU substitutes tissue/muscle. Also, it was found that the average value of the neutrons kerma coefficient for the 4 wicked tumors is from 6% to 7% smaller that the average value for the soft tissue in the interval energy of interest for therapy with fast neutrons with En > 1 MeV. These results have a special importance during the planning process of brachytherapy treatments with sources of 252Cf, to optimize and to individualize the patients treatments. (Author)

  3. Effect of tissue Inhomogeneities on dose distributions from Cf-252 brachytherapy source

    International Nuclear Information System (INIS)

    The Monte Carlo method was used to determine the effect of tissue inhomogeneities on dose distribution from a Cf-252 brachytherapy source. Neutron and gamma-ray fluences, energy spectra and dose rate distributions were determined in both homogenous and inhomogeneous phantoms. Simulations were performed using the MCNP5 code. Obtained results were compared with experimentally measured values published in literature. Results showed a significant change in neutron dose rate distributions in presence of heterogeneities. However, their effect on gamma rays dose distribution is minimal. - Highlights: ► The effect of tissue inhomogeneities on dose distribution has been investigated. ► A comparison of our results with experimental data available in the literature is presented. ► Obtained results showed a significant change in neutron dose rate distributions.

  4. Detailed dose distribution prediction of Cf-252 brachytherapy source with boron loading dose enhancement

    International Nuclear Information System (INIS)

    The purpose of this work is to evaluate the dose rate distribution and to determine the boron effect on dose rate distribution for 252Cf brachytherapy source. This study was carried out using a Monte Carlo simulation. To validate the Monte Carlo computer code, the dosimetric parameters were determined following the updated TG-43 formalism and compared with current literature data. The validated computer code was then applied to evaluate the neutron and photon dose distribution and to illustrate the boron loading effect.

  5. Detailed dose distribution prediction of Cf-252 brachytherapy source with boron loading dose enhancement

    Energy Technology Data Exchange (ETDEWEB)

    Ghassoun, J. [EPRA, Department of Physics, Faculty of Sciences Semlalia, PO Box: 2390, 40000 Marrakech (Morocco)], E-mail: ghassoun@ucam.ac.ma; Mostacci, D.; Molinari, V. [Laboratorio di Ingegneria Nucleare di Montecuccolino, via dei Colli 16, 40136 Bologna (Italy); Jehouani, A. [EPRA, Department of Physics, Faculty of Sciences Semlalia, PO Box: 2390, 40000 Marrakech (Morocco)

    2010-02-15

    The purpose of this work is to evaluate the dose rate distribution and to determine the boron effect on dose rate distribution for {sup 252}Cf brachytherapy source. This study was carried out using a Monte Carlo simulation. To validate the Monte Carlo computer code, the dosimetric parameters were determined following the updated TG-43 formalism and compared with current literature data. The validated computer code was then applied to evaluate the neutron and photon dose distribution and to illustrate the boron loading effect.

  6. Detailed dose distribution prediction of Cf-252 brachytherapy source with boron loading dose enhancement.

    Science.gov (United States)

    Ghassoun, J; Mostacci, D; Molinari, V; Jehouani, A

    2010-02-01

    The purpose of this work is to evaluate the dose rate distribution and to determine the boron effect on dose rate distribution for (252)Cf brachytherapy source. This study was carried out using a Monte Carlo simulation. To validate the Monte Carlo computer code, the dosimetric parameters were determined following the updated TG-43 formalism and compared with current literature data. The validated computer code was then applied to evaluate the neutron and photon dose distribution and to illustrate the boron loading effect. PMID:19889549

  7. Calculated neutron air kerma strength conversion factors for a generically encapsulated Cf-252 brachytherapy source

    CERN Document Server

    Rivard, M J; D'Errico, F; Tsai, J S; Ulin, K; Engler, M J

    2002-01-01

    The sup 2 sup 5 sup 2 Cf neutron air kerma strength conversion factor (S sub K sub N /m sub C sub f) is a parameter needed to convert the radionuclide mass (mu g) provided by Oak Ridge National Laboratory into neutron air kerma strength required by modern clinical brachytherapy dosimetry formalisms indicated by Task Group No. 43 of the American Association of Physicists in Medicine (AAPM). The impact of currently used or proposed encapsulating materials for sup 2 sup 5 sup 2 Cf brachytherapy sources (Pt/Ir-10%, 316L stainless steel, nitinol, and Zircaloy-2) on S sub K sub N /m sub C sub f was calculated and results were fit to linear equations. Only for substantial encapsulation thicknesses, did S sub K sub N /m sub C sub f decrease, while the impact of source encapsulation composition is increasingly negligible as Z increases. These findings are explained on the basis of the non-relativistic kinematics governing the majority of sup 2 sup 5 sup 2 Cf neutron interactions. Neutron kerma and energy spectra resul...

  8. Boron dose enhancement for Cf-252 brachytherapy

    International Nuclear Information System (INIS)

    Full text: Monte Carlo modelling of a Cf-252 source in water and in tissue has shown that there is a significant therapeutic advantage obtained if B-10 is present in the tumour cells. This study analyses the advantage in terms of therapeutic margin, defined as the distance from the border of the treatment volume where boron-loaded tumour cells will receive a therapeutic dose. Calculations were made with MCNP version 4a on a Pentium 60 MHz computer. Large voxel sizes allowed 70 minute runs to achieve statistical uncertainties of 5% or less for 100,000 source neutrons. Later runs with smaller voxels confirmed the accuracy of the initial calculations. Calculations were made for treatment volume radii up to 11 cm and 30 ppm boron-10. The therapeutic margin for radii in the range 3-9 cm is approximately 10% of the tumour radius. This results in a 30% increase in the volume inside which peripheral tumour cells may receive a therapeutic dose. The median therapeutic ratio within the therapeutic margin varied from 1.05 at 3 cm up to 1.25 at 10 cm. Thus there is little benefit for less advanced tumours with thickness less than 3 cm. However, cervical cancer frequently presents in an advanced state in Southeast Asia and in Aboriginal communities in Australia, partially attributable to low Pap smear screening rates. These conclusions support the development and testing of boron compounds in in vitro and in vivo models for cervical cancer

  9. A comparison of dosimetric parameters and dose distribution around CF -252 and IR-192 LDR Brachytherapy Sources

    International Nuclear Information System (INIS)

    Full text: The purpose of this work is the evaluation and comparison of the dose rate distributions around a 252Cf Applicator Tube (AT) and 192Ir LDR sources. The dosimetric parameters were determined for both sources according to the updated AAPM TG-43U1 protocol. The calculations were performed using the Monte Carlo N-particle MCNP code, version 5C. To validate the results of this study, they were compared to experimental and analytical dosimetric data available in the literature for similar source configurations. After validation, the Monte Carlo computer code was applied to investigate the difference between dose rate distributions around the two brachytherapy sources, with the purpose of comparing their efficiency in treatment. The data so obtained also provide further information about spatial dose distributions and are important for detailed treatment planning with 252 Cf or 192Ir LDR sources for interstitial and intracavitary therapy

  10. Ten-year cures of gynecologic tumors with Cf-252 neutron brachytherapy

    International Nuclear Information System (INIS)

    In 1976, Cf-252 was a novel and clinically untested fast-neutron-emitting radioisotope that had been proposed for neutron brachytherapy (NT). About 20 primary tumors had been treated; recurrences had been used to estimate a clinical RBE. Clinical trials at the University of Kentucky treated advanced cervical tumors with intracavitary Cf-252 NT with whole-pelvis photon radiation (50-60 Gy). Local control and up to 10-year survivals were achieved without significant side effects or secondary neoplasms (eg, hematologic malignancies). Treatments were done on an outpatient basis, were much shorter, were better tolerated by medically ill, bleeding, infected, or morbidly obese patients, and produced quicker tumor response with greatly reduced costs. Long-term outcome will be reviewed

  11. Comparative dosimetry in intracavitary balloon catheter brachytherapy with I-125 and in Cf-252 brachytherapy combined with BNCT for brain tumors

    OpenAIRE

    Samia de Freitas Brandao; Tarcisio Passos Ribeiro de Campos

    2013-01-01

    Objective Comparative analysis of dosimetry in intracavitary balloon catheter brachytherapy with I-125 and in Cf-252 brachytherapy combined with BNCT for treatment of brain tumors. Materials and Methods Simulations of intracavitary balloon catheter brachytherapy with I-125 and in Cf-252 brachytherapy combined with BNCT were performed with the MCNP5 code, modeling the treatment of a brain tumor on a voxel computational phantom representing a human head. Absorbed dose rates were converted int...

  12. Metronidazole in the treatment of cervical cancer using Cf-252 neutron brachytherapy

    International Nuclear Information System (INIS)

    Metronidazole was tested for its possible use in the Cf-252 brachytherapy of cervical cancer as a radiosensitizer and to deal with anaerobic pelvic infection. 15 patients were treated by only 14 were evaluable. All stages from stage IB-IVB were treated and complete local tumor regression was noted in all cases although it could take place very slowly. 5/14 (36%) are 1.5-3 year survivors but only among the patients with stage I-II disease. No unusual radio-enhancing action was observed but metronidazole appeared to be useful to treat the vaginal, cervix and uterine infections often associated with high stage disease and bulky, ulcerative or necrotic tumors

  13. Boron enhancement of high LET brachy-therapy using Cf-252

    International Nuclear Information System (INIS)

    The authors have used a discrete ordinates one dimensional transport code to analyse the potential enhancement of high LET event size spectra and absorbed dose around a Cf-252 implant used for treatment of glioblastoma multiforme. Toxicity effectively limits the concentration of boron in malignant brain tissues to 13-60 μg/gm at the time of treatment. Event size spectra from Cf-252 in a tissue equivalent proportional counter were used to estimate the number of high LET events per rad as a function of event size. The dose enhancement for these conditions will vary with the distance from the sources because the thermal neutron fluence is more uniform than the fast neutron fluence throughout the irradiated volume. The fast neutron dose is enhanced by as much as 60% at 5 cm., while the RBE dose enhancement is roughly 30% at this point. The number of events depositing more than 100 kev in a cell nucleus, however, is increased by at least a factor of 20 at 5 cm. These conditions will increase the effectiveness of brain tumor implants for tissues near the periphery to the extent that effective treatment depends on such high LET events

  14. Comparative dosimetry in intracavitary balloon catheter brachytherapy with I-125 and in Cf-252 brachytherapy combined with BNCT for brain tumors

    Energy Technology Data Exchange (ETDEWEB)

    Brandao, Samia de Freitas, E-mail: samiabrandao@gmail.com [Universidade Federal de Minas Gerais (UFMG), Belo Horizonte, MG (Brazil). Departamento de Engenharia Nuclear; Campos, Tarcisio Passos Ribeiro de [Universidade Federal de Minas Gerais (UFMG), Belo Horizonte, MG (Brazil)

    2013-06-15

    Objective: comparative analysis of dosimetry in intracavitary balloon catheter brachytherapy with I-125 and in Cf-252 brachytherapy combined with BNCT for treatment of brain tumors. Materials and methods: simulations of intracavitary balloon catheter brachytherapy with I-125 and in Cf-252 brachytherapy combined with BNCT were performed with the MCNP5 code, modeling the treatment of a brain tumor on a voxel computational phantom representing a human head. Absorbed dose rates were converted into biologically weighted dose rates. Results: intracavitary balloon catheter brachytherapy with I-125 produced biologically weighted mean dose rates of 3.2E-11, 1.3E-10, 1.9E-11 and 6.9E-13 RBE.Gy.h{sup -1}.p{sup -1}.s, respectively, on the healthy tissue, on the balloon periphery and on the /{sub 1} and /{sub 2} tumor infiltration zones. On the other hand, Cf-252 brachytherapy combined with BNCT produced a biologically weighted mean dose rate of 5.2E-09, 2.3E-07, 8.7E-09 and 2.4E-09 RBE.Gy.h{sup -1}.p{sup -1}.s, respectively on the healthy tissue, on the target tumor and on the /{sub 1} and /{sub 2} infiltration zones. Conclusion: Cf-252 brachytherapy combined with BNCT delivered a selective irradiation to the target tumor and to infiltration zones, while intracavitary balloon catheter brachytherapy with I-125 delivered negligible doses on the tumor infiltration zones. (author)

  15. Comparative dosimetry in intracavitary balloon catheter brachytherapy with I-125 and in Cf-252 brachytherapy combined with BNCT for brain tumors

    Directory of Open Access Journals (Sweden)

    Samia de Freitas Brandao

    2013-07-01

    Full Text Available Objective Comparative analysis of dosimetry in intracavitary balloon catheter brachytherapy with I-125 and in Cf-252 brachytherapy combined with BNCT for treatment of brain tumors. Materials and Methods Simulations of intracavitary balloon catheter brachytherapy with I-125 and in Cf-252 brachytherapy combined with BNCT were performed with the MCNP5 code, modeling the treatment of a brain tumor on a voxel computational phantom representing a human head. Absorbed dose rates were converted into biologically weighted dose rates. Results Intracavitary balloon catheter brachytherapy with I-125 produced biologically weighted mean dose rates of 3.2E-11, 1.3E-10, 1.9E-11 and 6.9E-13 RBE.Gy.h-1.p-1.s, respectively, on the healthy tissue, on the balloon periphery and on the I 1 and I 2 tumor infiltration zones. On the other hand, Cf-252 brachytherapy combined with BNCT produced a biologically weighted mean dose rate of 5.2E-09, 2.3E-07, 8.7E-09 and 2.4E-09 RBE.Gy.h-1.p-1.s, respectively on the healthy tissue, on the target tumor and on the I 1 and I 2 infiltration zones. Conclusion Cf-252 brachytherapy combined with BNCT delivered a selective irradiation to the target tumor and to infiltration zones, while intracavitary balloon catheter brachytherapy with I-125 delivered negligible doses on the tumor infiltration zones.

  16. Comparative dosimetry in intracavitary balloon catheter brachytherapy with I-125 and in Cf-252 brachytherapy combined with BNCT for brain tumors

    International Nuclear Information System (INIS)

    Objective: comparative analysis of dosimetry in intracavitary balloon catheter brachytherapy with I-125 and in Cf-252 brachytherapy combined with BNCT for treatment of brain tumors. Materials and methods: simulations of intracavitary balloon catheter brachytherapy with I-125 and in Cf-252 brachytherapy combined with BNCT were performed with the MCNP5 code, modeling the treatment of a brain tumor on a voxel computational phantom representing a human head. Absorbed dose rates were converted into biologically weighted dose rates. Results: intracavitary balloon catheter brachytherapy with I-125 produced biologically weighted mean dose rates of 3.2E-11, 1.3E-10, 1.9E-11 and 6.9E-13 RBE.Gy.h-1.p-1.s, respectively, on the healthy tissue, on the balloon periphery and on the /1 and /2 tumor infiltration zones. On the other hand, Cf-252 brachytherapy combined with BNCT produced a biologically weighted mean dose rate of 5.2E-09, 2.3E-07, 8.7E-09 and 2.4E-09 RBE.Gy.h-1.p-1.s, respectively on the healthy tissue, on the target tumor and on the /1 and /2 infiltration zones. Conclusion: Cf-252 brachytherapy combined with BNCT delivered a selective irradiation to the target tumor and to infiltration zones, while intracavitary balloon catheter brachytherapy with I-125 delivered negligible doses on the tumor infiltration zones. (author)

  17. Possibilities of detection of valuable metals in manganese nodules utilizing of Cf 252 neutron source

    International Nuclear Information System (INIS)

    For a long-term maintainance of the supply of non-iron metals the exploration of marine ore deposits becomes more and more important. In the special case of the so-called manganese nodules deposited on the deep ocean floor, a rather continuous method is required, by which the metals manganese, copper, nickel, cobalt and iron, or some of them, could be determined in situ, for short with an analytical error of about 20 to 50% analysis times. The possibility of performing such analyses by aid of the capture gamma radiation induced by a Cf 252 neutron source - which appeared to be promising - has been tested experimentally, simultaneous of referring to the maximum analizing time of 10 min demanded by application. For this purpose genuine manganese nodules have been irradiated at a 1 mg Cf 252 source. Decay gamma radiation as well as capture gamma radiation have been measured individually. The spectra from these measurements allowed to determine the statistical error of characteristic lines of the individual metal and thus their detectability. The measurement of decay gamma radiation (up to 2 MeV) showed that, within the short analyzing time, only manganese is detectable with a relative error of 1% referring to 10 g sample material. The measurement of capture gamma radiation (up to 10 MeV) verified the detection of the five metals of interest (Mn, Fe, Cu, Ni). An increase of the sample quantity up to 10 kg, corresponding to realistic prospection conditions, yielded within 10 min following relative errors: Mn 3 to 4%, Fe 7 to 8%, Cu 20 to 25%, Co 50% and Ni 12 to 20%. An experimental arrangement with the Cf 252 source and the sample situated in a water tank proved the practicability of such measurements even in presence of large quantities of water. (orig.)

  18. Effects of scattered neutrons on the neutron radiation field generated by Cf-252 neutron source with a shield

    International Nuclear Information System (INIS)

    Background: Shields are commonly constructed for a radionuclide neutron source m an actual calibration room in practice. Purpose: Monte Carlo (MC) calculation and experiments were applied to evaluate the effects of scattered neutrons on the neutron radiation field generated by Cf-252 neutron source with a shield. Methods: The effects of scattered neutrons caused by the shield of Cf-252 neutron source were evaluated by calculating the neutron spectra, neutron flux rate and neutron ambient dose equivalent with MC simulation. Similarly, the effects of scattered neutrons caused by the walls, ground and roof of source room were analyzed. Results: The calculation results show that the neutron flux-ambient dose equivalent conversion factor changes from 385 pSv·cm2 of a bare Cf-252 radionuclide from an idealized situation to 280 pSv·cm2 with the shield. The contribution of scattered neutrons from the walls, ground and roof is proportional to the square of distance between wall and source. The experimental data on dose rate are consistent with the calculated results and indicate the reliability of this method. Conclusion: This study provides a practical and feasible way to calibrate the radiation protection instruments using a non-standard radionuclide neutron radiation field. (authors)

  19. Neutron Spectra, Fluence and Dose Rates from Bare and Moderated Cf-252 Sources

    Energy Technology Data Exchange (ETDEWEB)

    Radev, Radoslav P. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

    2016-04-01

    A new, stronger 252Cf source (serial number SR-CF-3050-OR) was obtained from Oak Ridge National Laboratory (ORNL) in 2014 to supplement the existing 252Cf sources which had significantly decayed. A new instrument positioning track system was designed and installed by Hopewell Designs, Inc. in 2011. The neutron field from the new, stronger 252Cf source in the modified calibration environment needed to be characterized as well as the modified neutron fields produced by the new source and seven different neutron moderators. Comprehensive information about our 252Cf source, its origin, production, and isotopic content and decay characteristics needed to be compiled as well. This technical report is intended to address these issues.

  20. Cf-252 source-detector method for ADS and core reload in NPP's

    International Nuclear Information System (INIS)

    Accurate measurements of the subcritical level is an important research topic in the development of Accelerator Driven Systems (ADS) as well as for the determination of the subcriticality level in storage pools or during loading operations in LWR's. For ADS, it is clear that an accurate absolute determination of the subcriticality level is of paramount importance, since these systems are supposed to remain subcritical at all times. The core reload of NPP's is commonly executed by adopting the subcritical approach. This procedure allows to safely predicting the critical mass based on different subcritical states of the reactor, but it doesn't allow to obtain the subcriticality value of the different subcritical states during reload. Since practice in NPP's has shown that it would be very valuable to have access to the absolute value of the subcriticality, it is desirable to obtain a measurement technique that can be used for this purpose. In this project, we investigated the measurement of the multiplication factor keff in subcritical conditions in the VENUS reactor using the so-called 252Cf source-detector method. These measurements are the first step in the validation process of the 252Cf source-detector method to be used for subcriticality determination in ADS and during core reload in NPP's

  1. Xe-135 Production from Cf-252

    Energy Technology Data Exchange (ETDEWEB)

    C. A. McGrath; T. P. Houghton; J. K. Pfeiffer; R. K. Hague

    2012-03-01

    135Xe is a good indicator that fission has occurred and is a valuable isotope that helps enforce the Comprehensive Test Ban Treaty. Due to its rather short half life and minimal commercial interest, there are no known sources where 135Xe can be purchased. Readily available standards of this isotope for calibrating collection and analytical techniques would be very useful. 135Xe can be produced in the fissioning of actinide isotopes, or by neutron capture on 134Xe. Since the neutron capture cross section of 134Xe is 3 mB, neutron capture is a low yield, though potentially useful, production route. 135Xe is also produced by spontaneous fission of 252Cf. 252Cf has a spontaneous fission rate of about 6 x 1011 s-1g-1. The cumulative yield from the spontaneous fission of 252Cf is 4.19%; and the competing neutron capture reaction that depletes 135Xe in thermal reactor systems is negligible because the neutron capture cross-section is low for fast fission neutrons. At the INL, scientists have previously transported fission products from an electroplated 252Cf thin source for the measurement of nuclear data of short-lived fission products using a technique called He-Jet collection. We have applied a similar system to the collection of gaseous 135Xe, in order to produce valuable standards of this isotope.

  2. Use of neutron activation and X-ray fluorescence with radioactive sources (Cf-252 and Am-241) for the instrumental qualiquantitative simultaneous analysis of some elements in samples of mineral supplement for animals

    International Nuclear Information System (INIS)

    To study the possibility of using two non-destructive (neutron activation and X-ray fluorescence) analyses in simultaneous quali-quantitative evaluations of some elements in mineral supplement for animals, a Cf-252 neutron source (11.3 mCi; 21.1 μgrams) and a Am-241 low energy gamma-ray emitter source (59.5 KeV; 100 mCi) were employed. For these sources, shieldings and sample irradiation systems were built. For the neutron activation analysis a reservoir of 72 cm height and 43 cm diameter was filled with paraffine, and the samples and neutron sources were put inside this reservoir using polypropilene and nylon tubes. To detect the gamma-rays emitted by the radioisotopes a well-type solid NaI(Tl) crystal scintillator (3x3') was used, coupled to a multi-channel analyser. For the X-ray fluorescence analysis a lead cylinder of 9.75 cm height and 5.6 cm diameter (with 0.7 cm thickness) was made and internally lined with a 0.36 mm copper and 0.1 mm aluminium foil. (Author)

  3. HDR neutron brachytherapy for prostatic cancer in lithuania

    International Nuclear Information System (INIS)

    The purpose of this report is to analyse the physical and radiobiological background of the HDR Cf-252 Neutron brachytherapy boost in the combined radiation therapy for locally advanced prostatic cancer. The treatment schedule:two fractions of the Cf-252 brachytherapy(5Gy-eq at the dose point 2 cm from source movement trajectory) with interval 24 hours; 5-8 fractions of the photon beam external radiation therapy(5 fractions per week, 2 Gy per fraction) to the prostate, two fractions of the Cf-252 brachytherapy and after that external beam radiation therapy is continued till total dose 40-45 Gy. Six patients completed the proposed combined radiation therapy. The results of this trial will be discussed

  4. An absolute measurement of #-v# of Cf252

    International Nuclear Information System (INIS)

    An absolute measurement of v of Cf252. An absolute determination of the average number of neutrons, #-v#, emitted in the spontaneous fission of Cf252 has been made by counting the fission neutrons in a large liquid scintillator. The detection efficiency of this counter was measured as a function of neutron energy. Well-collimated neutrons were scattered into the scintillator by an anthracene crystal, which detected the corresponding recoil protons. Pulse-shape discrimination was employed to eliminate γ-ray background. The detection efficiency for Cf252 fission neutrons was found to be 0.703 ± 0.007, giving a value of 3.78 ± 0.04 for the average number of prompt neutrons emitted per Cf252 fission. (author)

  5. Theoretical analysis of the Cf-252 fission neutron spectrum

    International Nuclear Information System (INIS)

    A complex cascade evaporation model is used to analyse energy and angular distributions of Cf-252 fission neutrons for specified scission configurations. The sensitivity of the calculation with regard to the most important input data as well as certain approximations has been studied for typical fragment mass numbers. The paper includes a brief summary on the characteristics of the scission neutron component and its influence on energy spectra and angular distributions of fission neutrons. The model was also applied to calculate the distortion of the measurable Cf-252 fission neutron spectrum by the anisotropic fragment detection in time-of-flight spectrometer arrangements. (author)

  6. Performance evaluation of high-pressure MWPC with individual line readout under Cf-252 neutron irradiation

    International Nuclear Information System (INIS)

    A multiwire proportional chamber (MWPC) neutron detector system was developed for the Materials and Life Science Experimental Facility at the Japan Proton Accelerator Research Complex. Its basic performance was evaluated by an irradiation experiment using a Cf-252 neutron source. A short response time and high spatial resolution can be obtained using an individual line readout method. The detector system exhibited a one-dimensional uniformity of response of 4.8% and 3.8% in the x- and y-directions, respectively. The uniformity of all pixels in the two-dimensional image was 7.9%. The average intrinsic spatial resolution was 1.55 mm full width at half maximum in the sensitive region calculated by taking into account the track lengths of secondary particles. The signal intensity of the system remained constant during the operation for 500 min under Cf-252 neutron irradiation.

  7. Cf-252 based neutron radiography using real-time image processing system

    International Nuclear Information System (INIS)

    For compact Cf-252 based neutron radiography, a real-time image processing system by particle counting technique has been developed. The electronic imaging system consists of a supersensitive imaging camera, a real-time corrector, a real-time binary converter, a real-time calculator for centroid, a display monitor and a computer. Three types of accumulated NR image; ordinary, binary and centroid images, can be observed during a measurement. Accumulated NR images were taken by the centroid mode, the binary mode and ordinary mode using of Cf-252 neutron source and those images were compared. The centroid mode presented the sharpest image and its statistical characteristics followed the Poisson distribution, while the ordinary mode showed the smoothest image as the averaging effect by particle bright spots with distributed brightness was most dominant. (author)

  8. Averaged U238 fission cross section measurement in Cf-252 neutron spectrum

    International Nuclear Information System (INIS)

    With regard to the standardization of Cf-252 neutron spectrum, the averaged U-238 fission cross section was measured over the Cf-252 neutron spectrum using foil activation technique. The gamma spectra of the fission products were obtained on a pure germanium detector at different decay times in order to identify the gamma rays of short, medium and long half-life radioisotopes. Analyzing the gamma spectra of the irradiated uranium foils several distinct photopeaks of several fission products were identified. The pure activity of Te-132 was determined from the net area under 228.2 kev photopeak after correcting it for neighbouring photopeaks of Np-239 and Pa-234. The averaged U238 fission cross section was calculated from the corrected counts of Te-132 photopeak to be 329±10 mb. The main sources of errors in the measurements are mainly due to inaccuracy of location of foils, neutron flux, counting statistics, weight of foils, impurity of foils and interference from neighbouring photopeaks. The contribution of fission neutrons from spontaneous fission of Cm-248, daughter of Cf-252, to the total flux density was estimated at 0.13%. (orig.)

  9. Xe-135 production from Cf-252

    International Nuclear Information System (INIS)

    The presence of 135Xe is often used as an indicator that fission has occurred, and is used to help enforce the Comprehensive Test Ban Treaty. There are no known commercial suppliers, though it can be acquired. Readily available standards of this isotope are very useful. 135Xe can be produced through fission, or by neutron capture on 134Xe. At the INL, scientists have previously transported fission products from an electroplated 252Cf thin source for the measurement of nuclear data of short-lived fission products using a technique called He-Jet collection. A similar system has been applied to the collection of gaseous 135Xe, and 133Xe, in order to produce standards of these isotopes. (author)

  10. The legacy of Cf-252 operations at Savannah River Technology Center: Continuous releases of radioiodine to the atmosphere

    International Nuclear Information System (INIS)

    The iodine isotopes I-132, 1-133, I-134, and I-135, which have half-lives ranging from 53 minutes to 21 hours, are measured in the atmospheric effluent from the Savannah River Technology Center (SRTC) at the Savannah River Site (SRS) near Aiken, South Carolina. SRS is operated by Westinghouse Savannah River Company for the US Department of Energy (DOE). The isotopes' release rates range from 10 to 300 microcuries per week compared to the rate. The resulting annual dose from all iodine isotopes is minor; it comprises 0.01 percent of the total offsite dose due to atmospheric releases from SRS in 1990. Circumstantial evidence indicates the radioiodine originates from traces of unencapsulated Cf-252. The determination that spontaneous fission of Cf-252 is the source of the radioiodine has several ramifications. Radioactive fission-product isotopes of the noble gas elements krypton and xenon must also be released. Noble gases are more volatile and mobile than iodine. Also, the released iodine isotopes decay to xenon isotopes. The noble gases decay to non-gaseous elements that are transported along with radioiodine to the terrestrial environment by deposition from the SRTC plume. Only Sr-89 is believed to accumulate sufficiently in the environment to approach detectable levels. Given similar conditions in earlier years, releases of short-lived radioiodine have occurred undetected in routine monitoring since the early 1970s. Release rates 20 years ago would have been 200 times greater than current release rates. This report documents preliminary experiments conducted by SRTC and Environmental Monitoring Section (EMS) scientists. The release process and the environmental impact of fission products from Cf-252 should be thoroughly researched

  11. Atomic mass identification of CF-252 fission fragments using an NE-102 thin film detector

    International Nuclear Information System (INIS)

    The measurement of atomic number of low energy Cf-252 fission products using a three element thin film scintillation detector in conjunction with a residual energy solid state detector is described. Critical comparison of the separate spectra yielded by the three thin film elements is used to show both quantitative and qualitative consistency. Through the use of simple data handling techniques, increased resolution between peaks is easily obtained; the resultant spectrum for the distribution of both heavy and light fragments of Cf-252 is presented. The anticipated application of thin film scintillation techniques for event-by-event illucidation of decay schemes will also be discussed

  12. LARGE GAMMA ANISOTROPY OBSERVED IN THE CF-252 SPONTANEOUS-FISSION PROCESS

    NARCIS (Netherlands)

    VANDERPLOEG, H; BACELAR, JC; VANDENBERG, T; IACOB, VE; JONGMAN, [No Value; VANDERWOUDE, A

    1992-01-01

    The energy spectrum and the angular dependence relative to the fission direction of photons in the energy region between 2 and 40 MeV have been measured for the spontaneous fission of Cf-252. A large anisotropy was found in the energy region 8 to 12 MeV implying that photons in this region are emitt

  13. STUDY OF THE GAMMA EMISSION PROBABILITY ACCOMPANYING THE SPONTANEOUS FISSION OF CF-252

    NARCIS (Netherlands)

    VANDERPLOEG, H; LAURENS, CR; BACELAR, JCS; BUDA, A; GAARDHOJE, JJ; VANTHOF, G; KALANTARNAYESTANAKI, N; VANDERWOUDE, A; ZELAZNY, Z

    1994-01-01

    A study of the gamma emission accompanying the spontaneous fission process of Cf-252 has been performed. The photon emission probability between 3 and 70 MeV and its angular dependence with respect to the fission direction were measured. These measurements were performed as a function of the mass as

  14. Comparison of DD, DT and Cf-252 neutron excitation of light and medium mass nuclei for field PGNAA applications

    Energy Technology Data Exchange (ETDEWEB)

    Seabury, E.H. [Idaho National Laboratory, P.O. Box 1625 Idaho Falls, ID 8341-3840 (United States)]. E-mail: Edward.Seabury@inl.gov; Blackburn, B.W. [Idaho National Laboratory, P.O. Box 1625 Idaho Falls, ID 8341-3840 (United States); Chichester, D.L. [Idaho National Laboratory, P.O. Box 1625 Idaho Falls, ID 8341-3840 (United States); Wharton, C.J. [Idaho National Laboratory, P.O. Box 1625 Idaho Falls, ID 8341-3840 (United States); Caffrey, A.J. [Idaho National Laboratory, P.O. Box 1625 Idaho Falls, ID 8341-3840 (United States)

    2007-08-15

    Prompt Gamma Ray Neutron activation analysis can offer significant cost and safety advantages in the identification of explosives and toxic chemicals. As an example, the US military examined over a thousand suspect chemical munitions with Idaho National Laboratory's PINS Chemical Assay System last year. PGNAA requires, of course, a neutron source to excite the atomic nuclei of the item under test via neutron capture and inelastic neutron scattering reactions and the choice of neutron source can drastically affect PGNAA system performance. We have carried out Monte Carlo and laboratory experiments comparing DD, DT and Cf-252 neutrons incident on light and medium mass chemical elements, toward optimizing the design of future neutron-generator-based PGNAA systems for field use. We report the excitation of (n, {gamma}) and (n, n') gamma rays from these elements by each type of neutron source.

  15. Comparison of DD, DT and Cf-252 neutron excitation of light and medium mass nuclei for field PGNAA applications

    International Nuclear Information System (INIS)

    Prompt Gamma Ray Neutron activation analysis can offer significant cost and safety advantages in the identification of explosives and toxic chemicals. As an example, the US military examined over a thousand suspect chemical munitions with Idaho National Laboratory's PINS Chemical Assay System last year. PGNAA requires, of course, a neutron source to excite the atomic nuclei of the item under test via neutron capture and inelastic neutron scattering reactions and the choice of neutron source can drastically affect PGNAA system performance. We have carried out Monte Carlo and laboratory experiments comparing DD, DT and Cf-252 neutrons incident on light and medium mass chemical elements, toward optimizing the design of future neutron-generator-based PGNAA systems for field use. We report the excitation of (n, γ) and (n, n') gamma rays from these elements by each type of neutron source

  16. Comparison of DD, DT and Cf-252 neutron excitation of light and medium mass nuclei for field PGNAA applications

    Science.gov (United States)

    Seabury, E. H.; Blackburn, B. W.; Chichester, D. L.; Wharton, C. J.; Caffrey, A. J.

    2007-08-01

    Prompt Gamma Ray Neutron activation analysis can offer significant cost and safety advantages in the identification of explosives and toxic chemicals. As an example, the US military examined over a thousand suspect chemical munitions with Idaho National Laboratory's PINS Chemical Assay System last year. PGNAA requires, of course, a neutron source to excite the atomic nuclei of the item under test via neutron capture and inelastic neutron scattering reactions and the choice of neutron source can drastically affect PGNAA system performance. We have carried out Monte Carlo and laboratory experiments comparing DD, DT and Cf-252 neutrons incident on light and medium mass chemical elements, toward optimizing the design of future neutron-generator-based PGNAA systems for field use. We report the excitation of (n, γ) and (n, n‧) gamma rays from these elements by each type of neutron source.

  17. Fission-Neutron Spectra of U235, Pu239 And Cf252

    International Nuclear Information System (INIS)

    Measurements of the fission neutron spectra from the neutron-induced fission of U235 and Pu239, and the spontaneous fission of Cf252, have been made. The spectra were measured with a time-of-flight technique using a plastic scintillator as the fission-neutron detector. The low energy part of the Cf252 fission-neutron spectrum (below 0.3 MeV) was also measured with a Li6 -glass detector replacing the plastic scintillator. The fissile materials were mounted in xenon-gas scintillation cham-bers. The primary neutrons were produced by a 2.5-MeV Van de Graaff accelerator with top terminal pulsing. The resolving time of the time-of-flight equipment was better than 3 ns. Results fitted to Maxwellian distributions, √Ee-E/T, are presented for neutron-induced fissions of U235 at 40 keV and 1.5 MeV of incident neutron energy and for Pu239 at 40 keV. Results are also given for the fission-neutron energy spectrum of Cf252. (author)

  18. Observed branching ratios of alpha to fission fragments of Cf252 using CR-39

    International Nuclear Information System (INIS)

    There has been a rapid growth in the application of SSNTD to the study of nuclear phenomena in the recent past. The considerable ease introduced in recording the signature of heavy ions in the presence of alpha particles has made them particularly suitable for the study of spontaneous fission of transuranic elements. It is the object of the present study to explore the response of CR-39 for the determination of the branching ratios of alpha to fission fragments of Cf252 at the end of almost one and four half-life periods for alpha decay. The results more or less confirm the expected values

  19. Procedures for calibration of brachytherapy sources

    International Nuclear Information System (INIS)

    Brachytherapy source strength verification is a responsibility of the user of these source, in fact of the Medical Physicists in charge of this issue in a Radiotherapy Service. The calibration procedures in the users conditions are shown. Specifics methods for source strength determination are recommended, both for High Dose Rate (HDR) sources with Remote Afterloading equipment and for Low Dose Rate sources. The The results of the calibration of HDR Remote After loaders are indicated

  20. 10 CFR 35.432 - Calibration measurements of brachytherapy sources.

    Science.gov (United States)

    2010-01-01

    ... 10 Energy 1 2010-01-01 2010-01-01 false Calibration measurements of brachytherapy sources. 35.432 Section 35.432 Energy NUCLEAR REGULATORY COMMISSION MEDICAL USE OF BYPRODUCT MATERIAL Manual Brachytherapy § 35.432 Calibration measurements of brachytherapy sources. (a) Before the first medical use of...

  1. 10 CFR 35.406 - Brachytherapy sources accountability.

    Science.gov (United States)

    2010-01-01

    ... 10 Energy 1 2010-01-01 2010-01-01 false Brachytherapy sources accountability. 35.406 Section 35.406 Energy NUCLEAR REGULATORY COMMISSION MEDICAL USE OF BYPRODUCT MATERIAL Manual Brachytherapy § 35.406 Brachytherapy sources accountability. (a) A licensee shall maintain accountability at all...

  2. Brachytherapy

    Science.gov (United States)

    ... News Physician Resources Professions Site Index A-Z Brachytherapy What is Brachytherapy and how is it used? ... will I feel during this procedure? What is brachytherapy and how is it used? Brachytherapy is a ...

  3. Samarium-145: a new brachytherapy source

    International Nuclear Information System (INIS)

    A new radiation source has been produced for brachytherapy, with radiation energies slightly above those of 125I, and a Tsub(1/2) of 340 d. This source, 145Sm, is produced by neutron irradiation of 144Sm (96.5% enriched). Decay is by electron capture with 140 K x-rays per 100 disintergrations in the energy region between 38-45 keV, plus 13 γ-rays at 61 keV. These sources are encapsulated in Ti tubes, approx. 0.8 mm x 4.5 mm, and have been developed for temporary implantation in brain and ocular tumours. The 38-61 keV photons should make such sources easy to shield, while providing a dose distribution from source arrays somewhat more homogeneous than that from 125I. In addition, the 340 d half life of 145Sm permits its use for times significantly longer than that of 60 d 125I. While the 145Sm sources have been designed primarily for implantation in a brain tumour, they should be useful for almost any conventional brachytherapy application. (author)

  4. Numbers of prompt neutrons per fission for U233, U235, Pu239, and Cf252

    International Nuclear Information System (INIS)

    An absolute measurement of #-v#, the average number of prompt neutrons emitted per fission, is being made for the spontaneous fission of Cf262. The relative values of #-v# are being measured for neutron-induced fission of U233, U235, and Pu239, and are being compared with the spontaneous fission #-v# of Cf252. Neutrons with energies between thermal and 15 MeV are used. Particular emphasis is put on studying the dependence of #-v# on the incident neutron energy. A fission counter containing the appropriate isotope is placed in the centre of a large cadmium-loade d liquid scintillator. Through the fissionable isotope is passed a collimated beam of neutrons. Fission events, identified by pulses from the fission counter, open an electronic gate between the large liquid scintillator and a scaler. Scintillator pulses due to capture in the scintillating solution of thermalized fission neutrons are counted during the gate. The fission neutrons are detected almost independently of energy and with very high efficiency. With this technique values of #-v# to an accuracy of 1 % are expected. (author)

  5. Iridium-192 sources production for brachytherapy use

    International Nuclear Information System (INIS)

    The incidence of cancer increases every year in Brazil and turns out to be one of the most important causes of mortality. Some of the patients are treated with brachytherapy, a form of lesion treatment which is based on the insertion of sources into tumors, in this particular case, activated iridium wires. During this process, the ionizing radiation efficiently destroys the malignant cells. These iridium wires have a nucleus made out of an iridium-platinum alloy 20-30/70-80 of 0,1 mm in diameter either coated by platinum or encased in a platinum tube. The technique consists in irradiating the wire in the reactor neutron flux in order to produce iridium-192. The linear activity goes from 1 mCi/cm to 4 mCi/cm and the basic characteristic, which is required, is the homogeneity of the activation along the wire. It should not present a dispersion exceeding 5% on a wire measuring 50 cm in length, 0.5 mm or 0.3 mm in diameter. Several experiments were carried out in order to define the activation parameters. Wires from different origins were analyzed. It was concluded that United States of America and France wires were found to be perfectly adequate for brachytherapy purposes and have therefore been sent to specialized hospitals and successfully applied to cancer patients. Considering that the major purpose of this work is to make this product more accessible in Brazil, at a cost reflecting the Brazilian reality, the IPEN is promoting the preparation of iridium-192 sources to be used in brachytherapy, on a national level. (author)

  6. HeLa cell tumor response to 60Co, Cs-137, Cf-252 radiations and cisplatin chemotherapy in nude mice

    International Nuclear Information System (INIS)

    HeLa cells were implanted into athymic nude mice from tissue culture and solid tumors established (HeLa cell tumor or HCT). Large cell numbers of 1 X 107 were required to obtain consistent and progressive growth, and tumor growth followed a Gompertzian mode. Irradiation studies were carried out using acute Cobalt-60 (60Co), low-dose-rate (LDR) Cs-137 and LDR Cf-252. Cf-252, a neutron-emitting radioisotope, produced an immediate tumor shrinkage and regression response after a dose of 279 cGy. Acute 60Co or LDR Cs-137 irradiation with 1000 cGy had little effect on the HCT. After a dose of 2000 cGy of 60Co radiation tumor shrinkage followed a latent period of approximately 5 days. Cisplatin had no effect on the HCT in nude mice in stationary or late exponential growth

  7. OER by survival time for Cf-252, low dose rate Cs-137 and acute Co-60 for LSA lymphoma

    International Nuclear Information System (INIS)

    RBE and OER were determined for LSA tumor by survival time assay. The RBEn of Cf vs. Cs-137 was 5.8 and the OER was ∼ 1.4 by experiments performed in vitro and assayed in vivo. When tumor was irradiated in an advanced state in the living mouse, the RBEn was determined to be 5.2 vs. Cs-137. The RBE for hypoxic tumor is larger than for the oxic tumor for Cf-252 neutron irradiation. (Auth.)

  8. 10 CFR 35.400 - Use of sources for manual brachytherapy.

    Science.gov (United States)

    2010-01-01

    ... 10 Energy 1 2010-01-01 2010-01-01 false Use of sources for manual brachytherapy. 35.400 Section 35.400 Energy NUCLEAR REGULATORY COMMISSION MEDICAL USE OF BYPRODUCT MATERIAL Manual Brachytherapy § 35.400 Use of sources for manual brachytherapy. A licensee shall use only brachytherapy sources...

  9. Effects of G2102 for life prolongation of the mouse irradiated by neutron (Cf252 source)

    International Nuclear Information System (INIS)

    5 mrem/hr of neutron-dose was irradiated for 3 minutes in every two days to the mouse fed with alkaloid component of ginseng (G2102). The results are as follows: 1) LD50 of mouse (ICR species) is 3.75 mrem and the mouse survived more than 30 days with the neutron-dose of 0.25 mrem/days. 2) When the cancer-mouse was treated with neutron and G2102 together the life was increased by 221%. 3) The mouse which fed with G2102 for 35 days before neutron was irradiated with the dose of 4 mrem, were survived 100%. 4) By feeding G2102 for 20-35 days before the neutron irradiation, the serum γ-globulin and albumin were recovered 100%. 5) It is assumed that α-lipoprotein was decreased and chylomicron was increased by the neutron irradiation since the neutron inactivated the LPL (lipoprotein lipase). 6) Treatment of G2102 seems to be effective on the recovery of lymphocytes, however, it do not seem to be effective on the neutrophills in 30 days. (author)

  10. Survival of leukosis La cells after prolonged exposure to gamma-rays of Co60 and mixed gamma-neutron radiation of Cf252

    International Nuclear Information System (INIS)

    Survival curves of mouse leukosis La cells exposed in vitro to γ-rays of Co60 and γ/neutron radiation of Cf252 are characterized by the following parameters: an average lethal dose (D0) is 199.2 and 67.9 rad (for the neutron component), and the extrapolation number, 5.3 and 3.4, correspondingly. RBE of radiation from Cf252 is a function of the radiation dose, that is as the radiation dose increases the RBE decreases down to a minimum value of 1.7 for mixed irradiation and 2.2 for a purely neutron component

  11. Dosimetric characterization and output verification for conical brachytherapy surface applicators. Part I. Electronic brachytherapy source

    International Nuclear Information System (INIS)

    Purpose: Historically, treatment of malignant surface lesions has been achieved with linear accelerator based electron beams or superficial x-ray beams. Recent developments in the field of brachytherapy now allow for the treatment of surface lesions with specialized conical applicators placed directly on the lesion. Applicators are available for use with high dose rate (HDR)192Ir sources, as well as electronic brachytherapy sources. Part I of this paper will discuss the applicators used with electronic brachytherapy sources; Part II will discuss those used with HDR 192Ir sources. Although the use of these applicators has gained in popularity, the dosimetric characteristics including depth dose and surface dose distributions have not been independently verified. Additionally, there is no recognized method of output verification for quality assurance procedures with applicators like these. Existing dosimetry protocols available from the AAPM bookend the cross-over characteristics of a traditional brachytherapy source (as described by Task Group 43) being implemented as a low-energy superficial x-ray beam (as described by Task Group 61) as observed with the surface applicators of interest. Methods: This work aims to create a cohesive method of output verification that can be used to determine the dose at the treatment surface as part of a quality assurance/commissioning process for surface applicators used with HDR electronic brachytherapy sources (Part I) and192Ir sources (Part II). Air-kerma rate measurements for the electronic brachytherapy sources were completed with an Attix Free-Air Chamber, as well as several models of small-volume ionization chambers to obtain an air-kerma rate at the treatment surface for each applicator. Correction factors were calculated using MCNP5 and EGSnrc Monte Carlo codes in order to determine an applicator-specific absorbed dose to water at the treatment surface from the measured air-kerma rate. Additionally, relative dose

  12. Parameterization of brachytherapy source phase space file for Monte Carlo-based clinical brachytherapy dose calculation

    International Nuclear Information System (INIS)

    A common approach to implementing the Monte Carlo method for the calculation of brachytherapy radiation dose deposition is to use a phase space file containing information on particles emitted from a brachytherapy source. However, the loading of the phase space file during the dose calculation consumes a large amount of computer random access memory, imposing a higher requirement for computer hardware. In this study, we propose a method to parameterize the information (e.g., particle location, direction and energy) stored in the phase space file by using several probability distributions. This method was implemented for dose calculations of a commercial Ir-192 high dose rate source. Dose calculation accuracy of the parameterized source was compared to the results observed using the full phase space file in a simple water phantom and in a clinical breast cancer case. The results showed the parameterized source at a size of 200 kB was as accurate as the phase space file represented source of 1.1 GB. By using the parameterized source representation, a compact Monte Carlo job can be designed, which allows an easy setup for parallel computing in brachytherapy planning. (paper)

  13. Parameterization of brachytherapy source phase space file for Monte Carlo-based clinical brachytherapy dose calculation

    Science.gov (United States)

    Zhang, M.; Zou, W.; Chen, T.; Kim, L.; Khan, A.; Haffty, B.; Yue, N. J.

    2014-01-01

    A common approach to implementing the Monte Carlo method for the calculation of brachytherapy radiation dose deposition is to use a phase space file containing information on particles emitted from a brachytherapy source. However, the loading of the phase space file during the dose calculation consumes a large amount of computer random access memory, imposing a higher requirement for computer hardware. In this study, we propose a method to parameterize the information (e.g., particle location, direction and energy) stored in the phase space file by using several probability distributions. This method was implemented for dose calculations of a commercial Ir-192 high dose rate source. Dose calculation accuracy of the parameterized source was compared to the results observed using the full phase space file in a simple water phantom and in a clinical breast cancer case. The results showed the parameterized source at a size of 200 kB was as accurate as the phase space file represented source of 1.1 GB. By using the parameterized source representation, a compact Monte Carlo job can be designed, which allows an easy setup for parallel computing in brachytherapy planning.

  14. 10 CFR 35.490 - Training for use of manual brachytherapy sources.

    Science.gov (United States)

    2010-01-01

    ... 10 Energy 1 2010-01-01 2010-01-01 false Training for use of manual brachytherapy sources. 35.490 Section 35.490 Energy NUCLEAR REGULATORY COMMISSION MEDICAL USE OF BYPRODUCT MATERIAL Manual Brachytherapy § 35.490 Training for use of manual brachytherapy sources. Except as provided in § 35.57, the...

  15. 10 CFR 35.2432 - Records of calibration measurements of brachytherapy sources.

    Science.gov (United States)

    2010-01-01

    ... 10 Energy 1 2010-01-01 2010-01-01 false Records of calibration measurements of brachytherapy... Records § 35.2432 Records of calibration measurements of brachytherapy sources. (a) A licensee shall maintain a record of the calibrations of brachytherapy sources required by § 35.432 for 3 years after...

  16. [Brachytherapy].

    Science.gov (United States)

    Itami, Jun

    2014-12-01

    Brachytherapy do require a minimal expansion of CTV to obtain PTV and it is called as ultimate high precision radiation therapy. In high-dose rate brachytherapy, applicators will be placed around or into the tumor and CT or MRI will be performed with the applicators in situ. With such image-guided brachytherapy (IGBT) 3-dimensional treatment planning becomes possible and DVH of the tumor and organs at risk can be obtained. It is now even possible to make forward planning satisfying dose constraints. Traditional subjective evaluation of brachytherapy can be improved to the objective one by IGBT. Brachytherapy of the prostate cancer, cervical cancer, and breast cancer with IGBT technique was described. PMID:25596048

  17. 21 CFR 892.5730 - Radionuclide brachytherapy source.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Radionuclide brachytherapy source. 892.5730 Section 892.5730 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES RADIOLOGY DEVICES Therapeutic Devices § 892.5730 Radionuclide...

  18. MAGIC with formaldehyde applied to dosimetry of HDR brachytherapy source

    International Nuclear Information System (INIS)

    The use of polymer gel dosimeters in brachytherapy can allow the determination of three-dimensional dose distributions in large volumes and with high spatial resolution if an adequate calibration process is performed. One of the major issues in these experiments is the polymer gel response dependence on dose rate when high dose rate sources are used and the doses in the vicinity of the sources are to be determinated. In this study, the response of a modified MAGIC polymer gel with formaldehyde around an Iridium-192 HDR brachytherapy source is presented. Experimental results obtained with this polymer gel were compared with ionization chamber measurements and with Monte Carlo simulation with PENELOPE. A maximum difference of 3.10% was found between gel dose measurements and Monte Carlo simulation at a radial distance of 18 mm from the source. The results obtained show that the gel's response is strongly influenced by dose rate and that a different calibration should be used for the vicinity of the source and for regions of lower dose rates. The results obtained in this study show that, provided the proper calibration is performed, MAGIC with formaldehyde can be successfully used to accurate determinate dose distributions form high dose rate brachytherapy sources.

  19. Invited review, recent developments in brachytherapy source dosimetry

    International Nuclear Information System (INIS)

    Application of radioactive isotopes is the treatment of choice around the globe for many cancer sites. In this technique, the accuracy of the radiation delivery is highly dependent on the accuracy of radiation dosimetry around individual brachytherapy sources. Moreover, in order to have compatible clinical results, an identical method of source dosimetry must be employed across the world. This problem has been recently addressed by task group 43 from the American Association of Medical Physics with a protocol for dosimetric characterization of brachytherapy sources. This new protocol has been further updated using published data from international sources, by a new Task Group from the American Association of Medical Physics. This has resulted in an updated protocol known as TG43U1 that has been published in March 2004 issue of Medical Physics. The goal of this presentation is to review the original Task Group 43 protocol and associated algorithms for brachytherapy source dosimetry. In addition, the shortcomings of the original protocol that has been resolved in the updated recommendation will be highlighted. I am sure that this is not the end of the line and more work is needed to complete this task. I invite the scientists to join this task and complete the project, with the hope of much better clinical results for cancer patients

  20. Californium-252 brachytherapy for anal and ano-rectal carcinoma

    International Nuclear Information System (INIS)

    Surgery has historically been the standard treatment for anal, ano-rectal and rectal carcinoma but is prone to local or regional failure. Over the past 15 years there has been increasing interest in and success with radiation therapy and combined chemoradiotherapy for treatment of anal and ano-rectal cancers. Cf-252 brachytherapy combined with external beam teletherapy has been investigated for anal and ano-rectal lesions at the Univ. of Kentucky with encouraging results

  1. Cs-137 brachytherapy sources calibration with well chamber

    International Nuclear Information System (INIS)

    This work describes the procedures and actions developed for the identification and reference air kerma rate (Sk) verification of Cs-137 sources used in gynecological brachytherapy practices. Following the IAEA TECDOC 1151 recommendations, the first stage consisted in designing the documentation required for the inventory and shipping registry of sources, along with the digital spreadsheets for calculating the decay and Sk of the sources at the moment of implantation. As a second stage, the Sk of sources was measured, following the low dose rate sources protocol advise, with a Standard Imaging HDR 1000 Plus well chamber calibrated at the University of Wisconsin SSDL. The documentation generated through this procedure allows identify each source clearly and uni-vocally. No significant differences were found between the Sk values obtained from the well chamber calibration procedure and those reported by the manufacturer in the corresponding certificates. The highest percent difference found was 2.3%. (author)

  2. Calibration of brachytherapy sources. Guidelines on standardized procedures for the calibration of brachytherapy sources at Secondary Standard Dosimetry Laboratories (SSDLs) and hospitals

    International Nuclear Information System (INIS)

    Today, irradiation by brachytherapy is considered an essential part of the treatment for almost all the sites of cancer. With the improved localization techniques and treatment planning systems, it is now possible to have precise and reproducible dose delivery. However, the desired clinical results can only be achieved with a good clinical and dosimetric practice, i.e. with the implementation of a comprehensive quality assurance (QA) programme which includes detailed quality control procedures. As summarized in the present report, accidents in brachytherapy treatments have been caused due to the lack of traceable calibration of the sources, due to the incorrect use of quantities and units, or errors made in the dose calculation procedure. The International Basic Safety Standards for Protection against Ionizing Radiation and for the Safety of Radiation Sources has established a requirement on the calibration of sources used for medical exposure. For sources used in brachytherapy treatments, a calibration traceable to a standards dosimetry laboratory is required. The present report deals with the calibration of brachytherapy sources and related quality control (QC) measurements, QC of ionization chambers and safety aspects related to the calibration procedures. It does not include safety aspects related to the clinical use of brachytherapy sources, which have been addressed in a recent IAEA publication, IAEA-TECDOC-1040, 'Design and Implementation of a Radiotherapy Programme: Clinical, Medical Physics, Radiation Protection and Safety Aspects'. The procedures recommended in this report yield traceability to internationally accepted standards. It must be realized, however, that a comprehensive QA programme for brachytherapy cannot rest on source calibration alone, but must ensure QC of all the equipment and techniques that are used for the dose delivery to the patient. The present publication incorporates the reports of several consultants meetings in the field of

  3. Synthesis of phosphosilicate matrix for application to brachytherapy sources

    International Nuclear Information System (INIS)

    Brachytherapy with beta sources can be useful for in situ radiotherapy of cancers where tiny radioactive seeds are injected directly into the tumor. Phosphorus 31P can be activated to b-emitter 32P by neutron activation with a half-life of 14.3 days. In this work, phosphosilicate matrices were synthesized through sol-gel process by hydrolysis and condensation of the tetraethylorthosilicate (TEOS) under two different conditions of synthesis. In both conditions the phosphoric acid and drying control chemical additives (DCCA's) were the same. Three drying control chemical additives were utilized: propylene carbonate, N,N-dimethylformamide and ethylene glycol. The casting solutions were prepared with phosphorus content of 3.2 wt.% and xerogels were thermally treated at 900 deg C. Different microstructures were observed under different conditions of synthesis. The microstructures of phosphosilicate matrices obtained with ethylene glycol and without DCCA's have shown the presence of a globular structure regions with large amount of phosphorous. (author)

  4. Brachytherapy with 125-Iodine sources: transport and radiation protection

    International Nuclear Information System (INIS)

    The estimates for the year 2009 show that 466,730 new cancer cases will occur in Brazil. Prostate cancer is the second most incident type. Brachytherapy, a type of radiotherapy, with Iodine-125 sources are an important form of treatment for this kind of cancer. The Instituto de Pesquisas Energeticas e Nucleares (IPEN) created a project to develop a national prototype of these sources and is implementing a facility for local production. The seeds manufacture in Brazil will allow to diminish the treatment cost and make it possible for a larger number of patients. While the laboratory is not ready, the IPEN import and it distributes seeds. This work aim is to present and evaluate the transport procedures and the radiological protection applied to imported sources in order to assist the procedures for the new laboratory implementation. Before sending to hospitals, the seeds are packed by a radioprotector supervisor, in accordance with CNEN NE 5.01 standard 'Radioactive Material Transport'. Despite Iodine-125 presents low energy photons, around 29 keV, local and personal dosimeters are used during the transport process, as described in CNEN NN 3.01 standard 'Radiological Protection Basic Guideline'. All the results show no contamination and very low exposure, proving the method to be valid. The transport procedure used is correct, according to the regulations. As an result of this work, a new dosimeter should be installed and evaluate in future study. (author)

  5. Holmium-166-DTPA as a liquid source for endovascular brachytherapy

    International Nuclear Information System (INIS)

    Liquid radiation sources with β emitters have advantages of accurate positioning and uniform dose distribution to the vessel walls to prevent the restenosis of coronary artery. As a liquid radiation source, 166Ho-DTPA was prepared and evaluated its in-vivo pharmacokinetic behavior through animal studies. 166Ho-DTPA was prepared by simple mixing the Holmium with DTPA at room temperature. The radiolabelling yield was 100% when the DTPA/Holmium molar ratio was >2. Radiolabelling of 166Ho-DTPA was not dependent on the pH range of 1.7-7.5. High radiochemical stability (>98%) was maintained over a period of 6 hours even with a radioactivity (∼11.1 GBq/12 mg of DTPA) stored at room temperature. Biodistribution of 166Ho-DTPA in rats and gamma camera images in rabbits showed that 166Ho-DTPA was quickly excreted via the urinary system. The average of Tmax and T1/2 of 166Ho-DTPA in the kidneys of rabbits were 3.71 ± 1.18 min and 9.15 ± 3.15 min. 166Ho-DTPA is a potential liquid radiation source for radiation brachytherapy to prevent the restenosis of the coronary artery using a liquid-filled balloon

  6. Dose-rate to water calibrations for brachytherapy sources from the end-user perspective

    International Nuclear Information System (INIS)

    Independent primary standards for brachytherapy photon-emitting source calibration in terms of dose-rate to water have been developed within the framework of the Euramet T2.J06 project. The introduction of dose-rate to water calibration presents an important change in clinical brachytherapy dosimetry that is expected to result to improved dosimetric accuracy. Nevertheless, as with any change in dosimetry for radiation therapy purposes, a phase-in period of well concerted actions aimed at precluding ambiguities and accidents at the end-user level is necessary. The overall uncertainty budget of clinical brachytherapy applications, as well as current trends in brachytherapy treatment planning system dose-calculation algorithms, also need to be considered for a realistic assessment of the net benefit of improving source calibration accuracy. (authors)

  7. Studies on the development of 169Yb-brachytherapy seeds: New generation brachytherapy sources for the management of cancer

    International Nuclear Information System (INIS)

    This paper describes development of 169Yb-seeds by encapsulating 0.6–0.65 mm (ϕ) sized 169Yb2O3 microspheres in titanium capsules. Microspheres synthesized by a sol–gel route were characterized by XRD, SEM/EDS and ICP-AES. Optimization of neutron irradiation was accomplished and 169Yb-seeds up to 74 MBq of 169Yb could be produced from natural Yb2O3 microspheres, which have the potential for use in prostate brachytherapy. A protocol to prepare 169Yb-brachytherapy sources (2.96–3.7 TBq of 169Yb) with the use of enriched targets was also formulated

  8. Simulation of dose distribution for iridium-192 brachytherapy source type-H01 using MCNPX

    International Nuclear Information System (INIS)

    Dosimetric data for a brachytherapy source should be known before it used for clinical treatment. Iridium-192 source type H01 was manufactured by PRR-BATAN aimed to brachytherapy is not yet known its dosimetric data. Radial dose function and anisotropic dose distribution are some primary keys in brachytherapy source. Dose distribution for Iridium-192 source type H01 was obtained from the dose calculation formalism recommended in the AAPM TG-43U1 report using MCNPX 2.6.0 Monte Carlo simulation code. To know the effect of cavity on Iridium-192 type H01 caused by manufacturing process, also calculated on Iridium-192 type H01 if without cavity. The result of calculation of radial dose function and anisotropic dose distribution for Iridium-192 source type H01 were compared with another model of Iridium-192 source

  9. Simulation of dose distribution for iridium-192 brachytherapy source type-H01 using MCNPX

    Energy Technology Data Exchange (ETDEWEB)

    Purwaningsih, Anik [Center for development of nuclear informatics, National Nuclear Energy Agency, PUSPIPTEK, Serpong, Banten 15310 (Indonesia)

    2014-09-30

    Dosimetric data for a brachytherapy source should be known before it used for clinical treatment. Iridium-192 source type H01 was manufactured by PRR-BATAN aimed to brachytherapy is not yet known its dosimetric data. Radial dose function and anisotropic dose distribution are some primary keys in brachytherapy source. Dose distribution for Iridium-192 source type H01 was obtained from the dose calculation formalism recommended in the AAPM TG-43U1 report using MCNPX 2.6.0 Monte Carlo simulation code. To know the effect of cavity on Iridium-192 type H01 caused by manufacturing process, also calculated on Iridium-192 type H01 if without cavity. The result of calculation of radial dose function and anisotropic dose distribution for Iridium-192 source type H01 were compared with another model of Iridium-192 source.

  10. Source localisation and dose verification for a novel brachytherapy unit

    Science.gov (United States)

    Metaxas, Marinos G.

    A recent development in the field of radiotherapy has been the introduction of the PRS Intrabeam system (Carl Zeiss Surgical GmbH, Oberkochen, Germany). This is essentially a portable, miniaturised, electron-driven photon generator that allows high intensity, soft-energy x-rays (50 kVp) to be delivered directly to the tumour site in a single fraction. The system has been used for the interstitial radiation treatment of both brain and breast tumours. At present, a standardised in-vivo dose verification technique is not available for the PRS treatments. The isotropical distribution of photons about the tip of the PRS probe inserted in the tissue can effectively be viewed as a point source of radiation buried in the body. This work has looked into ways of localising the PRS source utilising its own radiation field. Moreover, the response of monoenergetic sources, mimicking realistic brachytherapy sources, has also been investigated. The purpose of this project was to attempt to localise the source as well as derive important dosimetric information from the resulting image. A detection system comprised of a well-collimated Germanium detector (HPGe) has been devised in a rotate-translate Emission Computed Tomography (ECT) modality. The superior energy resolving ability of the detection system allowed for energy selective reconstruction to be carried out in the case of the monoenergetic source (241Am). Results showed that the monoenergetic source can be localised to within 1 mm and the continuous PRS x-ray source to within 3mm. For the PRS dose map derivation, Monte Carlo studies have been employed in order to extract information on the dosimetric aspect of the resulting image. The final goal of this work was therefore to formulate a direct mathematical relation (Transform Map) between the image created by the escaping photons and the dose map as predicted by the theoretical model. The formation therefore of the in-vivo PRS image could allow for a real-time monitoring

  11. Guidelines for the calibration of low energy photon sources at beta-ray brachytherapy sources

    International Nuclear Information System (INIS)

    With the development of improved methods of implanting brachytherapy sources in a precise manner for treating prostate cancer and other disease processes, there has been a tremendous growth in the use of low energy photon sources, such as 125I and 103Pd brachytherapy seeds. Low energy photon sources have the advantage of easier shielding and also lowering the dose to normal tissue. However, the dose distributions around these sources are affected by the details in construction of the source and its encapsulation more than other sources used for brachytherapy treatments, such as 192Ir. With increasing number of new low energy photon sources on the market, care should be taken with regard to its traceability to primary standards. It cannot be assumed that a calibration factor for an ionization chamber that is valid for one type of low energy photon source, automatically is valid for another source even if both would use the same isotope. Moreover, the method used to calculate the dose must also take into account the structure of the source and the encapsulation. The dose calculation algorithm that is valid for one type of low energy source may not be valid for another source even if in both cases the same radionuclide is used. Simple ''point source'' approximations, i.e. where the source is modeled as a point, should be avoided, as such methods do not account for any details in the source construction. In this document, the dose calculation formalism adopted for low energy photon sources is that recommended by the American Association of Physicists in Medicine (AAPM) as outlined by Task Group-43 (TG-43). This method accounts for the source and capsule geometry. The AAPM recommends brachytherapy photon sources to be specified in terms of 'Air Kerma Strength' that is also used in the formalism mentioned above. On the other hand, the International Commission on Radiation Units and Measurements (ICRU) recommends that the specification be done in terms of Reference Air

  12. Production of 125I seed sources for brachytherapy uses

    International Nuclear Information System (INIS)

    The production of radioactive sources of 125I, used mainly for the brachytherapy of prostate and ocular cancer, is a work that is being carried out in the plant of production of radioisotopes (PPR) of the Nuclear Center Racso of the IPEN. The employed methodology is based on the 125I physical-chemistry adsorption at silver wires coated with palladium. In the realization of the tests, it has been considered the procedure used by India and Iran participants of this CRP. In the execution of this work, the 131I radioisotope is been used simulating the 125I, because in the PPR-IPEN we produce the 131I. In total 50 samples were used, they were divided in ten groups. In first place with nine working groups, the optimum conditions for work for the coating of the silver wires with palladium were obtained, these being the following: simple method, employing PdCl2 0.1 m, pH of 5.5 to 6.5 and a temperature of 100 deg. C. Later on, a series of tests were carried out to determine the appropriate parameters for the adsorption of 131I in the previously treated wires, these being the following: carrier concentration of Ki 0.03 m, time of adsorption of 6 hours, and temperature of 70 deg. C. Finally, the percentage of 131I adsorption was obtained in the silver wires tried previously with palladium chloride solution of 98.24%. The control of leachability was made, having very good results. To confirm these previously mentioned parameters, a test was made with ten pieces of silver wires, corresponding to the group 10, giving the confirmation as a result of these. Also, samples of the titanium tube have been sent for test with microplasma welding to a French company: air welding liquidates export. With these results obtained, subsequently the production of these radioactive sources will be carried out employing 125I as a radioisotope. (author)

  13. In vivo dosimetry thermoluminescence dosimeters during brachytherapy with a 370 GBq {sup 192}Ir source

    Energy Technology Data Exchange (ETDEWEB)

    Cuepers, S.; Piessens, M.; Verbeke, L.; Roelstraete, A. [Onze-Lieve-Vrouw Hospitaal, Aalst (Belgium). Dept. of Radiotherapy and Oncology

    1995-12-01

    When using LiF thermoluminescence dosimeters in brachytherapy, we have to take into account the properties of a high dose rate {sup 192}Ir source (energy spectrum ranging form 9 to 885 keV, steep dose gradient in the vicinity of the source) and these of the dosimeters themselves (supralinearity, reproducibility, size). All these characteristics combine into a set of correction factors which have been determined during in phantom measurements. These results have then been used to measure the dose delivered to organs at risk (e.g. rectum, bladder, etc.) during high dose rate brachytherapy with a 370 GBq {sup 192}Ir source for patients with gynaecological tumors.

  14. COMS eye plaque brachytherapy dosimetric sensitivity to source photon energy and seed design

    International Nuclear Information System (INIS)

    This study explores the influence of source photon energy on eye plaque brachytherapy dose distributions for a 16 mm COMS plaque filled with 103Pd, 125I, or 131Cs sources or monoenergetic photon emissions ranging from 12 keV to 100 keV. Dose distributions were similarly created for all permutations of three common brachytherapy seed designs. Within this range, sources with average energy ≤22 keV may reduce dose to the opposite eye wall by more than a factor of 2 while maintaining tolerable proximal sclera doses when prescribing to depths of 9 mm or less. Current commercially-available brachytherapy sources can exhibit up to 15% relative dosimetric sensitivity to seed design at regions within the eye. - Highlights: • Episcleral eye plaque brachytherapy utilizes low-energy photon-emitting sources. • Dose distribution sensitivity to source photon energy and seed design was examined. • Tumor dose conformity and critical structure sparing from ≤22 keV photons is preferred. • Ocular dose distributions varied by up to 15% with seed design permutations

  15. Clinical Practice and Quality Assurance Challenges in Modern Brachytherapy Sources and Dosimetry

    International Nuclear Information System (INIS)

    Modern brachytherapy has led to effective treatments through the establishment of broadly applicable dosimetric thresholds for maximizing survival with minimal morbidity. Proper implementation of recent dosimetric consensus statements and quality assurance procedures is necessary to maintain the established level of safety and efficacy. This review classifies issues as either 'systematic' or 'stochastic' in terms of their impact on large groups or individual patients, respectively. Systematic changes affecting large numbers of patients occur infrequently and include changes in source dosimetric parameters, prescribing practice, dose calculation formalism, and improvements in calculation algorithms. The physicist must be aware of how incipient changes accord with previous experience. Stochastic issues involve procedures that are applied to each patient individually. Although ample guidance for quality assurance of brachytherapy sources exists, some ambiguities remain. The latest American Association of Physicists in Medicine guidance clarifies what is meant by independent assay, changes source sampling recommendations, particularly for sources in sterile strands and sterile preassembled needles, and modifies action level thresholds. The changing environment of brachytherapy has not changed the fact that the prime responsibility for quality assurance in brachytherapy lies with the institutional medical physicist

  16. Establishment of the RSS reentrant chamber as a reference standard for brachytherapy sources

    International Nuclear Information System (INIS)

    Re-entrant chambers provide a reliable, sensitive and easy method for calibrating the brachytherapy sources, at the hospital site. This work reports on the establishment of the RSS well chamber, as a reference chamber, for the routine calibration of the hospital well chambers

  17. Biological effect of Pulsed Dose Rate brachytherapy with stepping sources

    International Nuclear Information System (INIS)

    Purpose: To explore the possible increase of radiation effect in tissues irradiated by pulsed brachytherapy (PDR), for local tissue dose-rates between those 'averaged over the whole pulse' and the instantaneous high dose rates close to the dwell positions. An earlier publication (Fowler and Mount 1992) had shown that, for dose rates (averaged for the duration of the pulse) up to 3 Gy/h, little change of isoeffect doses from continuous low dose rate (CLDR) are expected, unless larger doses per fraction than 1 Gy are used, and especially if components of very rapid repair are present with half-times of less than about 0.5 hours. However, local and transient dose rates close to stepping sources can be up to several Gy per minute. Methods: Calculations were done assuming the linear quadratic formula for radiation damage, in which only the dose-squared term is subject to repair, at a constant exponential rate. The formula developed by Dale for fractionated low-dose-rate radiotherapy was used. A constant overall time of 140 hours and constant total dose of 70 Gy were assumed throughout, the continuous low dose-rate of 0.5 Gy/h (CLDR) providing the unitary standard effects for each PDR condition. Effects of dose-rates ranging from 4 Gy/h to 120 Gy/h (HDR at 2 Gy/min) were studied, and T (1(2)) from 4 minutes to 1.5 hours. Results: Curves are presented relating the ratio of increased biological effect (proportional to log cell kill) calculated for PDR relative to CLDR. Ratios as high as 1.5 can be found for large doses per pulse (> 1 Gy) at high instantaneous dose-rates if T (1(2)) in tissues is as short as a few minutes. The major influences on effect are dose per pulse, half-time of repair in the tissue, and - when T (1(2)) is short - the instantaneous dose-rate. Maximum ratios of PDR/CLDR effect occur when the dose-rate is such that pulse duration is approximately equal to T (1(2)) of repair. Results are presented for late-responding tissues, the differences from CLDR

  18. Measurement of air kerma rate and absorbed dose for brachytherapy sources with secondary standard dosimeter

    International Nuclear Information System (INIS)

    The air kerma measurements for brachytherapy sources are generally recommended to be done at one meter using large volume chambers. These measurements pose problems due to low signal from brachytherapy sources. Non-availability of calibrated large volume chambers at a hospital adds to the problem of air kerma measurements. Therefore, the use of commonly available secondary standard dosimeter having 0.6 cc chambers has been examined. Correction factors to be applied at small source to chamber distances have been determined. Measurements from 137Cs source of nominal activity as low as 1.11 GBq (30 mCi) could be carried out using an integration time of about 20 minutes at minimum distance of 1.5 cm. For source to chamber distance beyond 5 cm, the correction factor approaches unity. (author)

  19. Measurement of anisotropic angular distributions of photon energy spectra for I-125 brachytherapy sources

    International Nuclear Information System (INIS)

    The angular distribution of photon energy spectra emitted from an I-125 brachytherapy source was measured using a specially designed jig in the range of ±70° in the plane of the long axis of the source. It is important to investigate the angular dependence of photon emissions from these sources for the calibration of the air kerma rate. The results show that the influence of the distributions between 0° and ±8° is small enough to allow a calibration using current primary instruments which have a large entrance window. - Highlights: ► Angular energy distribution for an I-125 brachytherapy source was measured. ► Variation of the distribution is sufficiently small. ► It is acceptable for primary calibration of the source strength. ► Distributions should be taken into consideration in some instruments.

  20. Determination of the Primary Nuclear Charge of Fission Fragments from their Characteristic K-X-Ray Emission in Spontaneous Fission of Cf252

    International Nuclear Information System (INIS)

    The distribution of nuclear charge in the spontaneous fission of Cf252 has been determined directly by simultaneous measurement of the masses and characteristic K-X-ray energies associated with the primary fission products. The X-rays were detected by a thin Nal (Tl) crystal (or by an argon-filled proportional counter) in coincidence with a pair of solid-state detectors for the complementary fission fragments. Preliminary to the three-parameter study of the charge-mass distribution the gross characteristics of the K-X-rays were examined in some detail. The average yield of K-X-rays is 0.55 ± 0.1 pet fission (the heavy group accounting fot 70% of the total). From delayed-coincidence and fragment time-of-flight experiments it was.found that about 30% of the X-rays are emitted within 0.1 ns after fission, another 30% between 0.1 and 1 ns, 25% between 1 and 10 ns, the remainder appearing as two delayed components of equal intensity with half-lives of ∼30 ns and ∼100 ns. These characteristics indicate that the X-rays arise from internal conversion during de-excitation of the primary fission fragments, an interpretation supported by the observed yield 1 per fission) of 50 - 300 - keV electrons emitted within 2 ps of fission. In the three-parameter experiments the yield and energy of K-X-rays emitted in the first centimeter (ns) of fragment flight were determined as a function of fragment mass. The yield of K-X-rays per fragment is a pronounced saw-tooth function of mass, rising from p) function in better agreement with the empirical rule of equal charge displacement (ECD) than with other postulates for charge division in nuclear fission. (author)

  1. Determination of the tissue inhomogeneity correction in high dose rate Brachytherapy for Iridium-192 source

    Directory of Open Access Journals (Sweden)

    Barlanka Ravikumar

    2012-01-01

    Full Text Available In Brachytherapy treatment planning, the effects of tissue heterogeneities are commonly neglected due to lack of accurate, general and fast three-dimensional (3D dose-computational algorithms. In performing dose calculations, it is assumed that the tumor and surrounding tissues constitute a uniform, homogeneous medium equivalent to water. In the recent past, three-dimensional computed tomography (3D-CT based treatment planning for Brachytherapy applications has been popularly adopted. However, most of the current commercially available planning systems do not provide the heterogeneity corrections for Brachytherapy dosimetry. In the present study, we have measured and quantified the impact of inhomogeneity caused by different tissues with a 0.015 cc ion chamber. Measurements were carried out in wax phantom which was employed to measure the heterogeneity. Iridium-192 (192 Ir source from high dose rate (HDR Brachytherapy machine was used as the radiation source. The reduction of dose due to tissue inhomogeneity was measured as the ratio of dose measured with different types of inhomogeneity (bone, spleen, liver, muscle and lung to dose measured with homogeneous medium for different distances. It was observed that different tissues attenuate differently, with bone tissue showing maximum attenuation value and lung tissue resulting minimum value and rest of the tissues giving values lying in between those of bone and lung. It was also found that inhomogeneity at short distance is considerably more than that at larger distances.

  2. Monte Carlo simulation of dosimetric parameters for hybrid PdI source in brachytherapy

    International Nuclear Information System (INIS)

    According to dose calculation formula recommended by AAPM TG-43U1, dose rate constant of' Model 6711 125I brachytherapy source was calculated by Monte Carlo method. The calculation results were in good agreement with TG-43U1. Then, dose rate constant, radial dose function and anisotropy function of new hybrid PdI source were calculated by Monte Carlo method. Empiric equations were obtained for radial dose function. (authors)

  3. Broad-beam transmission data for new brachytherapy sources, Tm-170 and Yb-169

    International Nuclear Information System (INIS)

    The characteristics of the radionuclides 170Tm and 169Yb are highly interesting for their use as high dose-rate brachytherapy sources. The introduction of brachytherapy equipment containing these sources will lead to smaller required thicknesses of the materials used in radiation protection barriers compared with the use of conventional sources such as 192Ir and 137Cs. The purpose of this study is to determine the required thicknesses of protection material for the design of the protecting walls. Using the Monte Carlo method, transmission data were derived for broad-beam geometries through lead and concrete barriers, from which the first half value layer and tenth value layer are obtained. In addition, the dose reduction in a simulated patient was studied to determine whether transmission in the patient is a relevant factor in radiation protection calculations. (authors)

  4. Dosimetry experience of 192IR sources used In HDR brachytherapy for cervical cancer

    International Nuclear Information System (INIS)

    Purpose/Objective: The 192IR Sources are the most commonly used in radiotherapy treatments HDR worldwide. According to international recommendations on quality assurance in HDR brachytherapy, an acceptance test based on the determination of the source strength of any new source shall be carried out before first application to verify the manufacturer’s calibration data. The present paper gives the experimental determination of the source strength for our brachytherapy sources used until now in brachytherapy treatments. Materials/Methods: At Mother Teresa University Hospital we have a cost-effective gynecological brachytherapy unit from Eckert & Ziegler BEBIG named GyneSource® that is a five channel HDR after loader equipped with an 192IR source. The software used is HDR plus™ 2.5 that delivers an optimized treatment plan and makes the process especially fast and we use intracavitary BEBIG applicators. From April 2009 up to December 2012, we have imported nine HDR 192IR Sources. The exchange of the source and acceptance test is done by the physicist of the clinic once the source is imported. The measurements are done with a Well-type ionization chamber HDR1000 Plus and the electrometer used is MAX4000. Only seven sources are compared as we miss the dosimetry data of the first source, and the forth source was not measured and not used because the machine was not working in that time. Results/Conclusions: Eight sources were accepted for clinically use as the measurement were within the tolerance. The source number four with e deviation of -1.92% has been double checked compared with a free in-air measurement with farmer type chamber that gave a deviation to source certificate of 4% that is still inside the tolerance to accept a source for clinical use. The deviations of measured Air Kerma rate to the value of the sources certificates of all our used 192IR sources are less than 2%, which are within the tolerance. The checked value of updated source strength in

  5. Novel high resolution 125I brachytherapy source dosimetry using Ge-doped optical fibres

    International Nuclear Information System (INIS)

    The steep dose gradients close to brachytherapy sources limit the ability to obtain accurate measurements of dose. Here we use a novel high spatial resolution dosimeter to measure dose around a 125I source and compare against simulations. Ge-doped optical fibres, used as thermoluminescent dosimeters, offer sub-mm spatial resolution, linear response from 10 cGy to >1 kGy and dose-rate independence. For a 125I brachytherapy seed in a PMMA phantom, doses were obtained for source-dosimeter separations from 0.1 cm up to several cm, supported by EGSnrc/DOSRZznrc Monte Carlo simulations and treatment planning system data. The measurements agree with simulations to within 2.3%±0.3% along the transverse and perpendicular axes and within 3.0%±0.5% for measurements investigating anisotropy in angular dose distribution. Measured and Veriseed™ brachytherapy treatment planning system (TPS) values agreed to within 2.7%±0.5%. Ge-doped optical fibre dosimeters allow detailed dose mapping around brachytherapy sources, not least in situations of high dose gradient. - Highlights: • We evaluate fall-off in dose for distances from an 125I source of 1 mm to 60 mm. • The TL of optical fibres accommodate high dose gradients and doses that reduce by a factor of 103 across the range of separations. • We verify measured values using DOSRZnrc Monte Carlo code simulations and the Variseed™ Treatment Planning System. • Measured radial and angular dose are obtained with ≤3% uncertainty

  6. Synthesis and characterization of hydroxyapatite porous matrixes for application as radiation sources in brachytherapy

    International Nuclear Information System (INIS)

    Porous ceramic materials based on calcium phosphate compounds (CPC) have been studied aiming at different biomedical applications such as implants, drug delivery systems and radioactive sources for brachytherapy. Two kinds of hydroxyapatite (HAp) powders and their ceramic bodies were characterized by a combination of different techniques (X-rays diffraction and fluorescence, infrared spectrophotometry, BET method, thermal analysis, and scanning electron microscopy) to evaluate their physico-chemical and microstructural characteristics in terms of chemical composition, segregated phases, microstructure, porosity, and chemical and thermal stability. The results revealed that these systems presented potential for use as porous biodegradable radioactive sources able to be loaded with a wide range of radionuclides for cancer treatment by the brachytherapy technique. (author)

  7. Comparison of 60Cobalt and 192Iridium sources in high dose rate afterloading brachytherapy

    International Nuclear Information System (INIS)

    Purpose: 60Co sources with dimensions identical to those of 192Ir have recently been made available in clinical brachytherapy. A longer half time reduces demands on logistics and quality assurance and perhaps costs. Material and Methods: Comparison of the physical properties of 60Co and 192Ir with regard to brachytherapy. Results: Required activities for the same air kerma rate are lower by a factor of 2.8 for 60Co. Differential absorption in tissues of different densities can be neglected. Monte Carlo calculations demonstrate that integral dose due to radial dose fall off is higher for 192Ir in comparison to 60Co within the first 22 cm from the source (normalization at 1 cm). At larger distances this relationship is reversed. Conclusion: Clinical examples for intracavitary and interstitial applications however, show practically identical dose distributions in the treatment volume. (orig.)

  8. Source position verification and dosimetry in HDR brachytherapy using an EPID

    International Nuclear Information System (INIS)

    Purpose: Accurate treatment delivery in high dose rate (HDR) brachytherapy requires correct source dwell positions and dwell times to be administered relative to each other and to the surrounding anatomy. Treatment delivery inaccuracies predominantly occur for two reasons: (i) anatomical movement or (ii) as a result of human errors that are usually related to incorrect implementation of the planned treatment. Electronic portal imaging devices (EPIDs) were originally developed for patient position verification in external beam radiotherapy and their application has been extended to provide dosimetric information. The authors have characterized the response of an EPID for use with an 192Ir brachytherapy source to demonstrate its use as a verification device, providing both source position and dosimetric information.Methods: Characterization of the EPID response using an 192Ir brachytherapy source included investigations of reproducibility, linearity with dose rate, photon energy dependence, and charge build-up effects associated with exposure time and image acquisition time. Source position resolution in three dimensions was determined. To illustrate treatment verification, a simple treatment plan was delivered to a phantom and the measured EPID dose distribution compared with the planned dose.Results: The mean absolute source position error in the plane parallel to the EPID, for dwells measured at 50, 100, and 150 mm source to detector distances (SDD), was determined to be 0.26 mm. The resolution of the z coordinate (perpendicular distance from detector plane) is SDD dependent with 95% confidence intervals of ±0.1, ±0.5, and ±2.0 mm at SDDs of 50, 100, and 150 mm, respectively. The response of the EPID is highly linear to dose rate. The EPID exhibits an over-response to low energy incident photons and this nonlinearity is incorporated into the dose calibration procedure. A distance (spectral) dependent dose rate calibration procedure has been developed. The

  9. Enhancement and validation of Geant4 Brachytherapy application on clinical HDR 192Ir source

    International Nuclear Information System (INIS)

    The Geant4 Monte Carlo MC associated Brachytherapy example was adapted, enhanced and several analysis techniques have been developed. The simulation studies the isodose distribution of the total, primary and scattered doses around a Nucletron microSelectron 192Ir source. Different phantom materials were used (water, tissue and bone) and the calculation was conducted at various depths and planes. The work provides an early estimate of the required number of primary events to ultimately achieve a given uncertainty at a given distance, in the otherwise CPU and time consuming clinical MC calculation. The adaptation of the Geant4 toolkit and the enhancements introduced to the code are all validated including the comprehensive decay of the 192Ir source, the materials used to build the geometry, the geometry itself and the calculated scatter to primary dose ratio. The simulation quantitatively illustrates that the scattered dose in the bone medium is larger than its value in water and tissue. As the distance away from the source increases, scatter contribution to dose becomes more significant as the primary dose decreases. The developed code could be viewed as a platform that contains detailed dose calculation model for clinical application of HDR 192Ir in Brachytherapy. - Highlights: • We enhanced and validated the Geant4 associated Brachytherapy code. • Primary and scattered doses from an actual 192Ir source are separated. • Different phantom materials are investigated. • The number of primary events to achieve a given uncertainty is provided. • A platform for detailed dose for clinical HDR Brachytherapy is established

  10. A design of brachytherapy source calibration template for air kerma rate/activity measurement

    International Nuclear Information System (INIS)

    This simple template can be used for the purpose of calibration of brachytherapy source, if the department does not have the calibration-track stand. One can design this template in the hospital itself as per the requirement, availability and facility, and the expenses also will be less. It is fully made up of a very thin 0.75 mm thickness of paper cardboard and this is the speciality. Currently this template is being utilized for accurate and easy calibration purposes

  11. Verification of I-125 brachytherapy source strength for use in radioactive seed localization procedures.

    Science.gov (United States)

    Metyko, John; Erwin, William; Landsberger, Sheldon

    2016-06-01

    A general-purpose nuclear medicine dose calibrator was assessed as a potential replacement for a dedicated air-communicating well-type ionization chamber (brachytherapy source strength verification instrument) for (125)I seed source strength verification for radioactive seed localization, where less stringent accuracy tolerances may be acceptable. The accuracy, precision and reproducibility of the dose calibrator were measured and compared to regulatory requirements. The results of this work indicate that a dose calibrator can be used for (125)I seed source strength verification for radioactive seed localization. PMID:27015651

  12. An orthodontic device for retaining implanted radioactive sources during brachytherapy for cancer of the oral cavity

    International Nuclear Information System (INIS)

    An orthodontic retainer was devised to keeping implanted radioactive sources in position and improve the quality of life during brachytherapy for cancer of the oral cavity. The retainer was used in 3 patients with oral cancer, one with cancer of the hard palate, one with cancer of the soft palate, and one with cancer of the floor of mouth, during brachytherapy using 198Au grains and 137Cs needles. These patients could speak freely. One with cancer of the hard palate could drink water and ingest semi-liquid food during treatment instead of nasal tube feeding. The plaster dental model obtained while making the retainer proved to be useful for training radiation oncologists. (author)

  13. Audit on source strength determination for HDR and PDR 192Ir brachytherapy in Sweden

    International Nuclear Information System (INIS)

    Background and purpose: To investigate the status of source strength determination in terms of reference air kerma rate (RAKR) for HDR and PDR 192Ir brachytherapy in Sweden. Materials and methods: RAKR was determined in each of the 14 Swedish afterloaders, using calibrated equipment from the Swedish Secondary Standard Dosimetry Laboratory. Results: Values of RAKR from the external audit, the hospitals and vendors agreed within the uncertainty limits guaranteed by the vendors. Conclusions: The accuracy in RAKR determination has increased over the last years as a result of increased availability of interpolation standards for HDR 192Ir and the increased use of robust well-type ion chambers designed for brachytherapy. It is recommended to establish a ratio between the RAKR value from own measurements at the hospital and that of the vendor since such a ratio embeds constant systematic differences due to e.g. varying traceability and therefore has the potential of being less uncertain than the RAKR alone. Traceability to primary standards for HDR 192Ir sources will in the future significantly decrease the uncertainty in RAKR of 192Ir brachytherapy

  14. Dosimetry audit on the accuracy of 192Ir brachytherapy source strength determinations in Sweden

    International Nuclear Information System (INIS)

    The absorbed dose delivered to the patient in brachytherapy is directly proportional to the source strength in terms of the reference air-kerma rate (RAKR). Verification of this quantity by the hospitals is widely recognized as an important part of a quality assurance program. An external audit was performed on behalf of the Secondary Standard Dosimetry Laboratory at the Swedish Radiation Protection Authority (SSI). The aim was to investigate how accurately the source-strength in 192Ir brachytherapy is determined at Swedish hospitals. The SSI reference well-type ion chamber and calibrated equipment were used to measure the RAKR of an 192Ir source in each of the 14 Swedish afterloading units. Comparisons with values determined by vendors and hospitals were made. Agreement in values of RAKR as determined by SSI, hospitals and vendors were in all cases within the ±3% uncertainty (at a coverage factor of k=2), typically guaranteed by the vendors. The good agreement reflects the robustness and easy handling of well-type chambers designed for brachytherapy in use by all Swedish hospitals. The 192Ir calibration service planned at SSI will solve the hospitals current problem with recalibration of equipment. SSI can also advise hospitals to follow the IAEA recommendations for measurement techniques and maintenance of equipment. It is worthwhile for the hospitals to establish their own ratio (or deviation) with the vendor and follow it as function of time. Such a mean-ratio embeds systematic differences of various origins and have a lower uncertainty than has the RAKR alone, making it useful for early detection of problems with equipment or routines. SSI could also define requirements for the agreement between source strengths as determined by hospitals and vendors and couple this to an action plan, dependent on level of disagreement, and some kind of reporting to SSI

  15. Clinical implementation of AAPM Task Group 32 recommendations on brachytherapy source strength specification

    International Nuclear Information System (INIS)

    Historically the strength of sealed brachytherapy sources has been described by many physical quantities, including true activity, apparent activity, and equivalent mass of radium. Recently, the AAPM Task Group 32 recommended that these quantities be replaced by a single quantity, air-kerma strength, with units of μGy m2 h-1. A set of equations has been developed for unambiguously converting source strength estimates and renormalizing published dose-rate tables, which assume traditional quantities and units, into forms consistent with air-kerma strength. For commonly used brachytherapy sources, multiplicative conversion factors for each source-strength formalism and set of units are given. To convert equivalent mass of radium to air-kerma strength requires a single multiplicative factor, 7.23 μGy m2 h-1/mgRaEq, applicable to all sources. Based upon a review of vendor source specification practices, the factors for converting source strength of 198Au, 103Pd, and 125I seeds from apparent mCi to air-kerma strength are 2.06, 1.29, and 1.27 μGy m2 h-1/mCi(apparent), respectively. These factors are independent of source geometry but depend on the nominal exposure rate constant value selected by the vendor. Conversion factors applicable to mass of radium or true activity depend upon both source geometry and radionuclide identity. Because many of these conversion factors depend upon vendor choices of physical constants and exposure rate constants, readers are cautioned to carefully review vendor source strength specification practices before adopting these values clinically. Finally, the relationships between the various source strength quantities and absorbed dose rate in the medium surrounding the source are elucidated

  16. Novel tools for stepping source brachytherapy treatment planning: Enhanced geometrical optimization and interactive inverse planning

    Energy Technology Data Exchange (ETDEWEB)

    Dinkla, Anna M., E-mail: a.m.dinkla@amc.uva.nl; Laarse, Rob van der; Koedooder, Kees; Petra Kok, H.; Wieringen, Niek van; Pieters, Bradley R.; Bel, Arjan [Department of Radiation Oncology, Academic Medical Center Amsterdam, Meibergdreef 9, Amsterdam 1105 AZ (Netherlands)

    2015-01-15

    Purpose: Dose optimization for stepping source brachytherapy can nowadays be performed using automated inverse algorithms. Although much quicker than graphical optimization, an experienced treatment planner is required for both methods. With automated inverse algorithms, the procedure to achieve the desired dose distribution is often based on trial-and-error. Methods: A new approach for stepping source prostate brachytherapy treatment planning was developed as a quick and user-friendly alternative. This approach consists of the combined use of two novel tools: Enhanced geometrical optimization (EGO) and interactive inverse planning (IIP). EGO is an extended version of the common geometrical optimization method and is applied to create a dose distribution as homogeneous as possible. With the second tool, IIP, this dose distribution is tailored to a specific patient anatomy by interactively changing the highest and lowest dose on the contours. Results: The combined use of EGO–IIP was evaluated on 24 prostate cancer patients, by having an inexperienced user create treatment plans, compliant to clinical dose objectives. This user was able to create dose plans of 24 patients in an average time of 4.4 min/patient. An experienced treatment planner without extensive training in EGO–IIP also created 24 plans. The resulting dose-volume histogram parameters were comparable to the clinical plans and showed high conformance to clinical standards. Conclusions: Even for an inexperienced user, treatment planning with EGO–IIP for stepping source prostate brachytherapy is feasible as an alternative to current optimization algorithms, offering speed, simplicity for the user, and local control of the dose levels.

  17. Novel tools for stepping source brachytherapy treatment planning: Enhanced geometrical optimization and interactive inverse planning

    International Nuclear Information System (INIS)

    Purpose: Dose optimization for stepping source brachytherapy can nowadays be performed using automated inverse algorithms. Although much quicker than graphical optimization, an experienced treatment planner is required for both methods. With automated inverse algorithms, the procedure to achieve the desired dose distribution is often based on trial-and-error. Methods: A new approach for stepping source prostate brachytherapy treatment planning was developed as a quick and user-friendly alternative. This approach consists of the combined use of two novel tools: Enhanced geometrical optimization (EGO) and interactive inverse planning (IIP). EGO is an extended version of the common geometrical optimization method and is applied to create a dose distribution as homogeneous as possible. With the second tool, IIP, this dose distribution is tailored to a specific patient anatomy by interactively changing the highest and lowest dose on the contours. Results: The combined use of EGO–IIP was evaluated on 24 prostate cancer patients, by having an inexperienced user create treatment plans, compliant to clinical dose objectives. This user was able to create dose plans of 24 patients in an average time of 4.4 min/patient. An experienced treatment planner without extensive training in EGO–IIP also created 24 plans. The resulting dose-volume histogram parameters were comparable to the clinical plans and showed high conformance to clinical standards. Conclusions: Even for an inexperienced user, treatment planning with EGO–IIP for stepping source prostate brachytherapy is feasible as an alternative to current optimization algorithms, offering speed, simplicity for the user, and local control of the dose levels

  18. Assessment of the risks associated with Iodine-125 handling production sources for brachytherapy

    Energy Technology Data Exchange (ETDEWEB)

    Souza, Daiane C.B.; Rostelato, Maria Elisa C.; Vicente, Roberto; Zeituni, Carlos A.; Tiezzi, Rodrigo; Costa, Osvaldo L.; Souza, Carla D.; Peleias Junior, Fernando S.; Rodrigues, Bruna T.; Souza, Anderson S.; Batista, Talita Q.; Melo, Emerson R.; Camargo, Anderson R., E-mail: dcsouza@usp.br [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil); Karam Junior, Dib, E-mail: dib.karam@usp.br [Universidade de Sao Paulo (USP), Sao Paulo, SP (Brazil)

    2015-07-01

    In Brazil, prostate cancer is the second most frequent disease, with an estimated 68,800 new cases in 2013. This type of cancer can be treated with brachytherapy, which uses sealed sources of Iodine-125 implanted permanently in the prostate. These sources are currently imported at a high cost, making public treatment in large scale impractical. To reduce costs and to meet domestic demand, the laboratory for production of brachytherapy sources at the Nuclear and Energy Research Institute (IPEN) is currently nationalizing the production of this radioisotope. Iodine is quite volatile making the handling of its radioactive isotopes potentially dangerous. The aim of this paper is to evaluate the risks to which workers are exposed during the production and handling of the sources. The research method consisted initially of a literature review on the toxicity of iodine, intake limits, related physical risks, handling of accidents, generation of radioactive wastes, etc. The results allowed for establishing safety and radioprotection policies in order to ensure efficient and safe production in all stages and the implementation of good laboratory practices. (author)

  19. A simplified analytical dose calculation algorithm accounting for tissue heterogeneity for low-energy brachytherapy sources.

    Science.gov (United States)

    Mashouf, Shahram; Lechtman, Eli; Beaulieu, Luc; Verhaegen, Frank; Keller, Brian M; Ravi, Ananth; Pignol, Jean-Philippe

    2013-09-21

    The American Association of Physicists in Medicine Task Group No. 43 (AAPM TG-43) formalism is the standard for seeds brachytherapy dose calculation. But for breast seed implants, Monte Carlo simulations reveal large errors due to tissue heterogeneity. Since TG-43 includes several factors to account for source geometry, anisotropy and strength, we propose an additional correction factor, called the inhomogeneity correction factor (ICF), accounting for tissue heterogeneity for Pd-103 brachytherapy. This correction factor is calculated as a function of the media linear attenuation coefficient and mass energy absorption coefficient, and it is independent of the source internal structure. Ultimately the dose in heterogeneous media can be calculated as a product of dose in water as calculated by TG-43 protocol times the ICF. To validate the ICF methodology, dose absorbed in spherical phantoms with large tissue heterogeneities was compared using the TG-43 formalism corrected for heterogeneity versus Monte Carlo simulations. The agreement between Monte Carlo simulations and the ICF method remained within 5% in soft tissues up to several centimeters from a Pd-103 source. Compared to Monte Carlo, the ICF methods can easily be integrated into a clinical treatment planning system and it does not require the detailed internal structure of the source or the photon phase-space. PMID:23965939

  20. Assessment of the risks associated with Iodine-125 handling production sources for brachytherapy

    International Nuclear Information System (INIS)

    In Brazil, prostate cancer is the second most frequent disease, with an estimated 68,800 new cases in 2013. This type of cancer can be treated with brachytherapy, which uses sealed sources of Iodine-125 implanted permanently in the prostate. These sources are currently imported at a high cost, making public treatment in large scale impractical. To reduce costs and to meet domestic demand, the laboratory for production of brachytherapy sources at the Nuclear and Energy Research Institute (IPEN) is currently nationalizing the production of this radioisotope. Iodine is quite volatile making the handling of its radioactive isotopes potentially dangerous. The aim of this paper is to evaluate the risks to which workers are exposed during the production and handling of the sources. The research method consisted initially of a literature review on the toxicity of iodine, intake limits, related physical risks, handling of accidents, generation of radioactive wastes, etc. The results allowed for establishing safety and radioprotection policies in order to ensure efficient and safe production in all stages and the implementation of good laboratory practices. (author)

  1. Energy-based dosimetry of low-energy, photon-emitting brachytherapy sources

    Science.gov (United States)

    Malin, Martha J.

    Model-based dose calculation algorithms (MBDCAs) for low-energy, photon-emitting brachytherapy sources have advanced to the point where the algorithms may be used in clinical practice. Before these algorithms can be used, a methodology must be established to verify the accuracy of the source models used by the algorithms. Additionally, the source strength metric for these algorithms must be established. This work explored the feasibility of verifying the source models used by MBDCAs by measuring the differential photon fluence emitted from the encapsulation of the source. The measured fluence could be compared to that modeled by the algorithm to validate the source model. This work examined how the differential photon fluence varied with position and angle of emission from the source, and the resolution that these measurements would require for dose computations to be accurate to within 1.5%. Both the spatial and angular resolution requirements were determined. The techniques used to determine the resolution required for measurements of the differential photon fluence were applied to determine why dose-rate constants determined using a spectroscopic technique disagreed with those computed using Monte Carlo techniques. The discrepancy between the two techniques had been previously published, but the cause of the discrepancy was not known. This work determined the impact that some of the assumptions used by the spectroscopic technique had on the accuracy of the calculation. The assumption of isotropic emission was found to cause the largest discrepancy in the spectroscopic dose-rate constant. Finally, this work improved the instrumentation used to measure the rate at which energy leaves the encapsulation of a brachytherapy source. This quantity is called emitted power (EP), and is presented as a possible source strength metric for MBDCAs. A calorimeter that measured EP was designed and built. The theoretical framework that the calorimeter relied upon to measure EP

  2. Dosimetric characterization of a brachytherapy source for gynaecological applications

    International Nuclear Information System (INIS)

    In this work Monte Carlo calculations and experimental measurements of dose rate in water per unit air-kerma strength, D/Sk, of a low dose rate Amersham CDCS.J 137Cs source are reported. The Monte Carlo calculations included a detailed simulation of the geometric structure of the source embedded in a water medium. The experimental procedure included the construction of a lucite phantom with the same geometric characteristics as the one used in the simulation. Dose measurements were performed using high spatial resolution RadioChromic dye film and TL dosemeters for short and large distances from the source, respectively. The comparison between simulated and reported values in the literature of D/Sk for the same source are of 1.0% in average [1]. The differences between the TL measurements and the simulation also are of 1% in average, while the difference between the MC and the RadioChromic film are larger, particularly when the RadioChromic film received doses smaller than 7 Gy

  3. TG-43 U1 based dosimetric characterization of model 67-6520 Cs-137 brachytherapy source

    International Nuclear Information System (INIS)

    Purpose: Brachytherapy treatment has been a cornerstone for management of various cancer sites, particularly for the treatment of gynecological malignancies. In low dose rate brachytherapy treatments, 137Cs sources have been used for several decades. A new 137Cs source design has been introduced (model 67-6520, source B3-561) by Isotope Products Laboratories (IPL) for clinical application. The goal of the present work is to implement the TG-43 U1 protocol in the characterization of the aforementioned 137Cs source. Methods: The dosimetric characteristics of the IPL 137Cs source are measured using LiF thermoluminescent dosimeters in a Solid Water phantom material and calculated using Monte Carlo simulations with the GEANT4 code in Solid Water and liquid water. The dose rate constant, radial dose function, and two-dimensional anisotropy function of this source model were obtained following the TG-43 U1 recommendations. In addition, the primary and scatter dose separation (PSS) formalism that could be used in convolution/superposition methods to calculate dose distributions around brachytherapy sources in heterogeneous media was studied. Results: The measured and calculated dose rate constants of the IPL 137Cs source in Solid Water were found to be 0.930(±7.3%) and 0.928(±2.6%) cGy h-1 U-1, respectively. The agreement between these two methods was within our experimental uncertainties. The Monte Carlo calculated value in liquid water of the dose rate constant was Λ=0.948(±2.6%) cGy h-1 U-1. Similarly, the agreement between measured and calculated radial dose functions and the anisotropy functions was found to be within ±5%. In addition, the tabulated data that are required to characterize the source using the PSS formalism were derived. Conclusions: In this article the complete dosimetry of the newly designed 137Cs IPL source following the AAPM TG-43 U1 dosimetric protocol and the PSS formalism is provided.

  4. Near-catheter dosimetry of a HDR brachytherapy source using Gafchromic film

    International Nuclear Information System (INIS)

    High dose rate intraluminal brachytherapy treatments can be delivered using as few as one or two afterloading catheters, delivering doses of up to 10 Gy at 10 mm, leading to high dose gradients and extreme hot spots close to the catheter. These conditions have the potential to damage the patient's health tissues, possibly leading to necrosis, or even death from uncontrolled bleeding. Ionisation chambers and solid state detectors are limited in their usefulness for near-catheter dosimetry because of their physical size and in some cases energy and dose rate dependence. In contrast, radiochromic film has a large dose–response range, excellent spatial resolution, near-energy independence for megavoltage photons and the ability to measure dose in two dimensions, making it ideal for this application. The aim of this study was to measure the location and relative magnitude of any dosimetric hot spots produced by a typical endobronchial treatment plan. The study also investigated the effect of the step size of the 192Ir source on both the dose hot spots and dose distribution. Our measurements show that for a typical single catheter treatment with 2.5 mm step size the maximum dose hot spots at the catheter surface are up to 37 times the prescription dose, up to 40 times for a 5 mm step size, and up to 46 times for a 10 mm step size. It is important that brachytherapy clinicians and physicists understand that hot spot magnitude increases with source step sizes and are aware of the risks associated with this form of brachytherapy treatment.

  5. Development of high-activity 252Cf sources for neutron brachytherapy

    International Nuclear Information System (INIS)

    The Gershenson Radiation Oncology Center of Wayne State University (WSU), Detroit, Michigan, is using 252Cf medical sources for neutron brachytherapy. These sources are based on a 20-year-old design containing ≤ 30 microg 252Cf in the form of a cermet wire of Cf2O3 in a palladium matrix. The Radiochemical Engineering Development Center (REDC) of Oak Ridge National Laboratory has been asked to develop tiny high-activity 252Cf neutron sources for use with remote afterloading equipment to reduce treatment times and dose to clinical personnel and to expedite treatment of brain and other tumors. To date, the REDC has demonstrated that 252Cf loadings can be greatly increased in cermet wires much smaller than before. Equipment designed for hot cell fabrication of these wires is being tested. A parallel program is under way to relicense the existing source design for fabrication at the REDC

  6. Development of automated measurement system for radioactive intensities of sealed small radiation sources (iodine-125 seed source) for brachytherapy

    International Nuclear Information System (INIS)

    We have developed full automated measurement system for radioactive intensities of sealed small radiation sources (iodine-125 seed source) for brachytherapy in this work. Today, quality assurance (QA) of I-125 seed radioactive sources for brachytherapy following AAPM (American Association of Physicists in Medicine) Society's guideline is one of important subjects for hospitals that operate on patients for prostate cancer and medical companies that manufacture and sell these radioactive sources. In order to survey defective seed products into all the number of I-125 seed sources (there are usually fifteen seeds, one seed of dimensions is 0.8 mm φ × 4.5 mm length) within a cartridge, we have applied the method of single slit collimator with moving a radiation detector to measure each radioactive intensity of these I-125 seeds. As a result, it was found that our developed system in the present work has good performance of surveying the defective products manufactured with radioactive intensities out of about ±15% error (p < 0.05). (author)

  7. Monte Carlo angular dose distribution of the microselectron HDR 192Ir brachytherapy source

    International Nuclear Information System (INIS)

    Polar dose profiles around the Nucletron MicroSelectron high dose rate (HDR) 192Ir brachytherapy source were calculated using the Monte Carlo radiation transport code MCNP (Monte Carlo N Particle) version 4A. The geometry modeled consisted of an identical simulation of the construction of the MicroSelectron HDR source located at the centre of a spherical water phantom of 100cm radius. Doses were calculated using a spherical coordinate system at 5 degree intervals (measured relative to the cable) at radii of 0.25, 0.5,1.0, 3.0, 5.0 and 7.0cm. These polar doses were compared to equivalent profiles from the Nucletron PLATO Brachytherapy Planning System (BPS) version 13.X. At 3.0, 5.0 and 7.0cm radii, the Monte Carlo and BPS profiles are generally within 3%. The near field polar dose profiles however, are in significant disagreement. At 1.0cm radius, the discrepancy can exceed 5%. At 0.5cm this figure rises to 15%, and even 60% at 0.25cm radius

  8. Standardization of the calibration of brachytherapy sources at the IAEA dosimetry laboratory

    International Nuclear Information System (INIS)

    A new service to SSDLs has been initiated at the IAEA Dosimetry Laboratory for providing calibrations of well-type ionisation chambers, used in brachytherapy applications, which are traceable to the International Measurement System. Considering that the most common radionuclide used in the developing countries is 137Cs, two such sources of the type used for gynaecological intracavitary applications have been purchased by the Agency and calibrated at the National Institute of Standards and Technology (NIST), USA. These 137Cs reference sources together with a well-type ionization chamber constitute the IAEA brachytherapy dosimetry standard. Based on the recommendations by a group of experts, a method has been developed for transferring calibrations to SSDLs which is described in this paper. The method is based on the acquisition by the SSDLs of sources and equipment similar to those at the IAEA. The well-type chamber is to be calibrated at the IAEA Dosimetry Laboratory, and this will be used at the SSDL to calibrate its own reference sources. These sources can in turn by used to calibrate well-type chambers from hospital users and to calibrate other type of sources by performing measurements in air. In order to standardize the procedures for the two methods and to provide guidance to the SSDLs, measurements have been carried out at the IAEA Dosimetry Laboratory. The reproducibility of the two type of measurements has been found to be better than 0.5%, and the uncertainty of calibrations estimated to be less than 1.5% (one standard deviation). (author). 8 refs, 8 figs, 2 tabs

  9. Comparison between methods for fixing radioactive iodine in silver substrate for manufacturing brachytherapy sources

    International Nuclear Information System (INIS)

    Among the different ways to treat prostate cancer, brachytherapy with iodine- 125 seeds is an option that provides good results and fewer side effects. In the present study several deposition methods of radioactive iodine in a silver substrate were compared in order to choose the most suitable alternative for the routine production to be implemented at IPEN's laboratory. The methodology used was chosen based on the available infrastructure and experience of the researchers present. Therefore, the 131I was used for testing (same chemical behavior as 131I). Four methods were selected: Method 1 (test based on electrodeposition method developed by D.Kubiatowicz) presented 65.16% efficiency; Method 2 (chemical reaction based on the method developed by D. Kubiatowicz - HCl) with the result of 70.80% efficiency; method 3 (chemical reaction based on the method developed by Dr. Maria Elisa Rostelato) with 55.80% efficiency; Method 4 (IQ-IPEN) resulted in 99% efficiency. Since this method has more radioactive material fixation (which represents virtually the entire cost of the seed), the final price is the cheapest. This method is the suggested one to be implemented in the IPEN's laboratory for brachytherapy sources production. Besides, the method is the fasted one. (author)

  10. The history of brachytherapy in Russia: comparison of 60Co vs. 192Ir sources

    International Nuclear Information System (INIS)

    Brachytherapy is known as the first historical method of radiotherapy. At the beginning of its development it was used only as manual applications of liquid solutions of nuclides. Only from the middle of 1950-th specialized machines for automatic afterloading have been designed. The first types of the machines were those with pneumatically driven pellets of 137Cs. The main advantage of this nuclide is its long half-life time of about 30 years resulting in long periods between source replacements. But due to the same reason, it is impossible to provide high source activity within small pellets. So those machines can be defined as those of low dose rate (less than 2 Gy/hr.). Patients had to spend up to 1-3 days with applicators inserted to obtain the full therapeutic dose of 24 Gy

  11. Microdosimetric evaluation of relative biological effectiveness for 103PD, 125I, 241AM, and 192IR brachytherapy sources

    International Nuclear Information System (INIS)

    Purpose: To determine the microdosimetric-derived relative biological effectiveness (RBE) of 103Pd, 125I, 241Am, and 192Ir brachytherapy sources at low doses and/or low dose rates. Methods and Materials: The Theory of Dual Radiation Action can be used to predict expected RBE values based on the spatial distribution of energy deposition at microscopic levels from these sources. Single-event lineal energy spectra for these isotopes have been obtained both experimentally and theoretically. A grid-defined wall-less proportional counter was used to measure the lineal energy distributions. Unlike conventional Rossi proportional counters, the counter used in these measurements has a conducting nylon fiber as the central collecting anode and has no metal parts. Thus, the Z-dependence of the photoelectric effect is eliminated as a source of measurement error. Single-event spectra for these brachytherapy sources have been also calculated by: (a) the Monte Carlo code MCNP to generate the electron slowing down spectrum, (b) transport of monoenergetic electron tracks, event by event, with our Monte Carlo code DELTA, (c) using the concept of associated volume to obtain the lineal energy distribution f(y) for each monoenergetic electron, and (d) obtaining the composite lineal energy spectrum for a given brachytherapy source based on the electron spectrum calculated at step (a). Results: Relative to 60Co, the RBE values obtained from this study are: 2.3 for 103Pd, 2.1 for 125I, 2.1 for 241Am, and 1.3 for 192Ir. Conclusions: These values are consistent with available data from in vitro cell survival experiments. We suggest that, at least for these brachytherapy sources, microdosimetry may be used as a credible alternative to time-consuming (and often uncertain) radiobiological experiments to obtain information on radition quality and make reliable predictions of RBE in low dose rate brachytherapy

  12. Five-year cure of cervical cancer treated using californium-252 neutron brachytherapy

    International Nuclear Information System (INIS)

    Female pelvic carcinoma is one of the common malignancies seen at the University of Kentucky Medical Center and often presents in an advanced stage. In 1976, the authors began to test californium-252 neutron brachytherapy (NT) for its efficacy for control of primary and recurrent advanced uterine, cervix, and vaginal cancers. The first protocol used was 5000-5500 rad of whole pelvis irradiation followed by 1-2 Cf-252 insertions using a single tandem placed in the utero-cervico-vaginal region. Of 27 patients with primary carcinomas treated, 10 are alive and well 5 year later (37%). Two of two recurrent tumors were locally controlled but failed later. These patients had advanced cervical, vaginal, or endometrial carcinomas. In 1977, a transitional year, treatment of only unfavorable stages and presentations with NT was initiated. Similar results were obtained with NT as compared to conventional photon therapy (PT). Further improvement in treatment results can be anticipated as NT brachytherapy is used for advanced cancer therapy by more effective treatment schedules and radiation doses. Cf-252 can be used as a radium substitute and achieved similar rates of tumor control and 5-year survivals. 21 references, 2 tables

  13. Endovascular brachytherapy: dosimetry and dose-area analysis of various radiation sources

    International Nuclear Information System (INIS)

    With the increase in popularity of endovascular brachytherapy for prevention of restenosis following coronary angioplasty, it remains to be determined which isotope and isotope form is the most ideal. An issue concerning the use of wire sources is the influence of the centering of the wire on dose uniformity across the artery wall and the potential problems this can lead to in terms of underdosage of the target tissues. In this investigation, the dosimetric characteristics of three currently used sources (γ-emitting 192Ir wire; β-emitting 32P wire; and β-emitting 188Re solution) were determined with EGS4 Monte Carlo. The dose results were then used to determine the dose-area relationships for the three sources in arteries with concentric and non-concentric lumens/walls, including situations in which the wire sources are moved away from the centre of the artery. It is found that, in order to ensure dose uniformity, centering is substantially more important for β-emitting wire sources. This is highlighted most significantly in the case of an example large irregular artery. Although the suitability of a source depends on many criteria (e.g., cost, availability, radiation protection, possible radiation-induced late effects), the problem of centering a wire source in possibly large and/or irregular arteries is greatly eased by the use of a γ-emitting source. Copyright (2001) Australasian College of Physical Scientists and Engineers in Medicine

  14. Verification of high dose rate 192Ir source position during brachytherapy treatment

    International Nuclear Information System (INIS)

    A system for in vivo tracking of 1 Ci 192Ir source during brachytherapy treatment has been built using high resistivity silicon pad detectors as image sensors and knife-edge lead pinholes as collimators. The sensors consist of 256 pads arranged in 32 x8 grid with pad size 1.4x1.4mm2 and 1 mm thickness. The sensors have two metal layers, enabling connection of readout electronics (VATAGP31 chips) at the edge of the detector. With source self-images obtained from a dual-pinhole system, location of the source can be reconstructed in three dimensions in real time, allowing on-line detection of deviations from planned treatment. The system was tested with 1 Ci 192Ir clinical source in air and plexi-glass phantom. The movements of the source could be tracked in a field of view of approximately 20x20x20cm3 with absolute precision of about 5 mm. Positions of the source, relative to the first measured source position, could be mapped with precision of around 3 mm.

  15. Investigations into the Optimization of Multi-Source Strength Brachytherapy Treatment Procedures

    CERN Document Server

    Henderson, D L; Yoo, S

    2002-01-01

    The goal of this project is to investigate the use of multi-strength and multi-specie radioactive sources in permanent prostate implant brachytherapy. In order to fulfill the requirement for an optimal dose distribution, the prescribed dose should be delivered to the target in a nearly uniform dose distribution while simultaneously sparing sensitive structures. The treatment plan should use a small number of needles and sources while satisfying the treatment requirements. The hypothesis for the use of multi-strength and/or multi-specie sources is that a better treatment plan using fewer sources and needles could be obtained than by treatment plans using single-strength sources could reduce the overall number of sources used for treatment. We employ a recently developed greedy algorithm based on the adjoint concept as the optimization search engine. The algorithm utilizes and ''adjoint ratio'', which provides a means of ranking source positions, as the pseudo-objective function. It ha s been shown that the gre...

  16. Calibration of photon and beta ray sources used in brachytherapy. Guidelines on standardized procedures at Secondary Standards Dosimetry Laboratories

    International Nuclear Information System (INIS)

    It has generally been recognized that international harmonization in radiotherapy dosimetry is essential. Consequently, the IAEA has given much effort to this, for example by publishing a number of reports in the Technical Reports Series (TRS) for external beam dosimetry, most notably TRS-277 and more recently TRS-398. Both of these reports describe in detail the steps to be taken for absorbed dose determination in water and they are often referred to as 'dosimetry protocols'. Similar to TRS-277, it is expected that TRS-398 will be adopted or used as a model by a large number of countries as their national protocol. In 1996, the IAEA established a calibration service for low dose rate (LDR) 137 Cs brachytherapy sources, which is the most widely used source for treatment of gynecological cancer. To further enhance harmonization in brachytherapy dosimetry, the IAEA published in 1999 IAEA-TECDOC-1079 entitled 'Calibration of Brachytherapy Sources. Guidelines on Standardized Procedures for the Calibration of Brachytherapy Sources at Secondary Standard Dosimetry Laboratories (SSDLs) and Hospitals'. The report was well received and was distributed in a large number of copies to the members of the IAEA/WHO network of SSDLs and to medical physicists working with brachytherapy. The present report is an update of the aforementioned TECDOC. Whereas TECDOC-1079 described methods for calibrating brachytherapy sources with photon energies at or above those of 192Ir, the current report has a wider scope in that it deals with standardization of calibration of all the most commonly used brachytherapy sources, including both photon and beta emitting sources. The latter sources have been in use for a few decades already, but their calibration methods have been unclear. Methods are also described for calibrating sources used in the rapidly growing field of cardiovascular angioplasty. In this application, irradiation of the vessel wall is done in an attempt to prevent restenosis after

  17. RADIOLOGICAL CRITERIA FOR PATIENT RELEASE FROM CLINIC AFTER RADIONUCLIDE THERAPY OF BRACHYTHERAPY WITH SEALED SOURCE IMPLANTATION

    Directory of Open Access Journals (Sweden)

    M. I. M.I. Balonov

    2016-03-01

    Full Text Available Dose criteria for limitation of exposure incurred by persons helping the patients or living with patients discharged from hospitals following radionuclide therapy or brachytherapy with implanted sealed radionuclide sources have been proposed for national Russian regulation. By means of a conservative dosimetry model, the values of operational radiological criteria for patient discharge from hospital are substantiated, i.e. whole body activity for radionuclides 125I,131I,153Sm and 188Re as well as dose rate near patient body. Observance of suggested criteria included in the new Russian Standards for Radiation Safety (RSS-99/2009 will ensure radiation safety of people in near environment (family, close friends et ah.

  18. Comparison between methods for fixing radioactive iodine in silver substrate for manufacturing brachytherapy sources

    International Nuclear Information System (INIS)

    Cancer is a term used generically to represent a group of more than 100 illnesses, including malignant tumors from different locations. According to World Health Organization (WHO), is a leading cause of death worldwide, accounted for 7.6 million deaths. Prostate cancer is the sixth most common type in the world, representing about 10% of all cases of cancer and its treatment may be by surgery, radiotherapy or even vigilant observation. A method of radiotherapy which has been extensively used in the early and intermediate stages of the illness is brachytherapy, where radioactive seeds are placed inside or next to the area requiring treatment, which reduces the probability of unnecessary damage to surrounding healthy tissues. Currently, the radioactive isotope Iodine-125, adsorbed on silver substrate, is one of the most used in prostate brachytherapy. The present study compares several deposition methods of radioactive Iodine on silver substrate, in order to choose the most suitable one to be implemented at the laboratory of radioactive sources production of IPEN. The methodology used was chosen based on the available infrastructure and experience of the researchers of the institute. Therefore, Iodine-131 was used for testing (same chemical behavior of Iodine -125). Three methods were selected: method 1 (test based on electrodeposition method, developed by David Kubiatowicz) which presented efficiency of 65.16% ; method 2 (chemical reaction based on the method developed by David Kubiatowicz -HCl) which presented efficiency of 70.80%; method 3 (chemical reaction based on the method developed by Dr. Maria Elisa Rostelato) which presented efficiency of 55.80% . Based on the results, the second method is the suggested one to be implemented at the laboratory of radioactive sources production of IPEN. (author)

  19. Performance assessment of the BEBIG MultiSource high dose rate brachytherapy treatment unit.

    Science.gov (United States)

    Palmer, Antony; Mzenda, Bongile

    2009-12-21

    A comprehensive system characterisation was performed of the Eckert & Ziegler BEBIG GmbH MultiSource High Dose Rate (HDR) brachytherapy treatment unit with an (192)Ir source. The unit is relatively new to the UK market, with the first installation in the country having been made in the summer of 2009. A detailed commissioning programme was devised and is reported including checks of the fundamental parameters of source positioning, dwell timing, transit doses and absolute dosimetry of the source. Well chamber measurements, autoradiography and video camera analysis techniques were all employed. The absolute dosimetry was verified by the National Physical Laboratory, UK, and compared to a measurement based on a calibration from PTB, Germany, and the supplied source certificate, as well as an independent assessment by a visiting UK centre. The use of the 'Krieger' dosimetry phantom has also been evaluated. Users of the BEBIG HDR system should take care to avoid any significant bend in the transfer tube, as this will lead to positioning errors of the source, of up to 1.0 mm for slight bends, 2.0 mm for moderate bends and 5.0 mm for extreme curvature (depending on applicators and transfer tube used) for the situations reported in this study. The reason for these errors and the potential clinical impact are discussed. Users should also note the methodology employed by the system for correction of transit doses, and that no correction is made for the initial and final transit doses. The results of this investigation found that the uncorrected transit doses lead to small errors in the delivered dose at the first dwell position, of up to 2.5 cGy at 2 cm (5.6 cGy at 1 cm) from a 10 Ci source, but the transit dose correction for other dwells was accurate within 0.2 cGy. The unit has been mechanically reliable, and source positioning accuracy and dwell timing have been reproducible, with overall performance similar to other existing HDR equipment. The unit is capable of high

  20. Neutron brachytherapy for the treatment of malignant neoplasia

    International Nuclear Information System (INIS)

    In the 1930's both neutrons and the cyclotron were discovered, developed and used almost immediately for neutron beam therapy. Cf-252 was discovered in 1950 but its potential for cancer therapy was not postulated until 1965. Early sporadic clinical trials were used to treat only a few patients. The recognition of its curative properties and usefulness for bulky localized and radioresistant cancer therapy was not made until recently. In 1985, the Lexington Workshop led to a sharing of independent experiences from the USA, Japan, and the USSR; early trial experiences were related to neutron beam results. Localized neutron therapy using brachytherapy methods was found effective against radioresistance and bulky tumors. However, it needed to be used properly and with full appreciation of clinical oncology and the role of photon adjuvant therapy

  1. Monte Carlo modeling of 60 Co HDR brachytherapy source in water and in different solid water phantom materials

    Directory of Open Access Journals (Sweden)

    Sahoo S

    2010-01-01

    Full Text Available The reference medium for brachytherapy dose measurements is water. Accuracy of dose measurements of brachytherapy sources is critically dependent on precise measurement of the source-detector distance. A solid phantom can be precisely machined and hence source-detector distances can be accurately determined. In the present study, four different solid phantom materials such as polymethylmethacrylate (PMMA, polystyrene, Solid Water, and RW1 are modeled using the Monte Carlo methods to investigate the influence of phantom material on dose rate distributions of the new model of BEBIG 60 Co brachytherapy source. The calculated dose rate constant is 1.086 ± 0.06% cGy h−1 U−1 for water, PMMA, polystyrene, Solid Water, and RW1. The investigation suggests that the phantom materials RW1 and Solid Water represent water-equivalent up to 20 cm from the source. PMMA and polystyrene are water-equivalent up to 10 cm and 15 cm from the source, respectively, as the differences in the dose data obtained in these phantom materials are not significantly different from the corresponding data obtained in liquid water phantom. At a radial distance of 20 cm from the source, polystyrene overestimates the dose by 3% and PMMA underestimates it by about 8% when compared to the corresponding data obtained in water phantom.

  2. Calibration of a 192Ir source for high dose brachytherapy using various techniques

    International Nuclear Information System (INIS)

    In this research we studied three experimental procedures for calibration of a source of 192Ir to high dose rate for clinical brachytherapy use, and thus were compared and analysis of the advantages and disadvantages of each. For this study we quantified the value of the current kerma rate reference in air by three procedures: source calibration using a well chamber, with an cylindrical ionization chamber in air, and a cylindrical ionization chamber on a phantom, and this magnitude was compared with the value provided by the manufacturer of the source and thereby obtaining the deviation corresponding . Thus, it was found that the deviation corresponding to the source calibration making use of a well chamber, remained within tolerance, while the cylindrical ionization chamber in air and on phantom exceeded the standards established in some documents. However, although both the measurement in air and in the phantom are the procedures for the final calibration source, these can be used to verify that the delivered dose are in tolerance.

  3. Influence of radioactive sources discretization in the Monte Carlo computational simulations of brachytherapy procedures: a case study on the procedures for treatment of prostate cancer

    International Nuclear Information System (INIS)

    Radiotherapy computational simulation procedures using Monte Carlo (MC) methods have shown to be increasingly important to the improvement of cancer fighting strategies. One of the biases in this practice is the discretization of the radioactive source in brachytherapy simulations, which often do not match with a real situation. This study had the aim to identify and to measure the influence of radioactive sources discretization in brachytherapy MC simulations when compared to those that do not present discretization, using prostate brachytherapy with Iodine-125 radionuclide as model. Simulations were carried out with 108 events with both types of sources to compare them using EGSnrc code associated to MASH phantom in orthostatic and supine positions with some anatomic adaptations. Significant alterations were found, especially regarding bladder, rectum and the prostate itself. It can be concluded that there is a need to discretized sources in brachytherapy simulations to ensure its representativeness. (author)

  4. Methodology study for fixation of radioactive iodine in polymeric substrate for brachytherapy sources

    International Nuclear Information System (INIS)

    Cancer is now the second leading cause of death by disease in several countries, including Brazil. Prostate cancer is the most common among men. Brachytherapy is a modality of radiotherapy in which radioactive seeds are placed inside or in contact with the organ to be treated. The most widely used radioisotope in prostate brachytherapy is Iodine-125 which is presented fixated on a silver substrate that is subsequently placed inside a titanium capsule. A large dose of radiation is released only in the targeted tumor protecting healthy surrounding tissues. The technique requires the application of 80 - 120 seeds per patient. The implants of seeds have low impact and non-surgical procedures. Most patients can return to normal life within three days with little or no pain. This work proposes an alternative to the seeds that have already been developed, in order to reduce the cost by obtaining a better efficiency on fixing the radioactive iodine onto the epoxy resin. Methods have been developed to perform the fixation of Iodine-125 onto polymeric substrates. The parameters analyzed were the immersion time, type of static or dynamic reaction, concentration of the adsorption solution, the specific activity of the radioactive source, the need for carrier and chemical form of the radioactive Iodine. These experiments defined the most effective method to fixate the Iodine onto the polymeric material (epoxy resin), the Iodine activity in the polymeric substrate, the activity of the distribution of variation in a plot of polymeric cores and the efficiency of the epoxy resin to seal the seed. (author)

  5. Methodology study for fixation of radioactive iodine in polymeric substrate for brachytherapy sources

    Energy Technology Data Exchange (ETDEWEB)

    Rodrigues, Bruna T.; Rostelato, Maria Elisa C.M.; Souza, Carla D.; Tiezzi, Rodrigo; Souza, Daiane B. de; Benega, Marcos A.G.; Souza, Anderson S. de; Peleias Junior, Fernando S.; Zeituni, Calos A.; Fernandes, Vagner; Melo, Emerson Ronaldo de; Camargo, Anderson Rogerio de, E-mail: bteigarodrigues@gmail.com [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil)

    2015-07-01

    Cancer is now the second leading cause of death by disease in several countries, including Brazil. Prostate cancer is the most common among men. Brachytherapy is a modality of radiotherapy in which radioactive seeds are placed inside or in contact with the organ to be treated. The most widely used radioisotope in prostate brachytherapy is Iodine-125 which is presented fixated on a silver substrate that is subsequently placed inside a titanium capsule. A large dose of radiation is released only in the targeted tumor protecting healthy surrounding tissues. The technique requires the application of 80 - 120 seeds per patient. The implants of seeds have low impact and non-surgical procedures. Most patients can return to normal life within three days with little or no pain. This work proposes an alternative to the seeds that have already been developed, in order to reduce the cost by obtaining a better efficiency on fixing the radioactive iodine onto the epoxy resin. Methods have been developed to perform the fixation of Iodine-125 onto polymeric substrates. The parameters analyzed were the immersion time, type of static or dynamic reaction, concentration of the adsorption solution, the specific activity of the radioactive source, the need for carrier and chemical form of the radioactive Iodine. These experiments defined the most effective method to fixate the Iodine onto the polymeric material (epoxy resin), the Iodine activity in the polymeric substrate, the activity of the distribution of variation in a plot of polymeric cores and the efficiency of the epoxy resin to seal the seed. (author)

  6. Chemical digestion and radionuclidic assay of TiNi-encapsulated 32P intravascular brachytherapy sources

    International Nuclear Information System (INIS)

    A very quantitative, destructive assay procedure was devised for accurately measuring the 32P activity content of TiNi-encapsulated intravascular brachytherapy sources and was applied to four different sources (termed 'seeds') which were developed and provided by Guidant Intravascular Intervention (formerly NeoCardia). These seeds are intended for use in the prophylactic treatment of restenosis following balloon angioplasty in heart-disease patients. The assays involved the dissolution of the TiNi jacket, extraction of the activity from the internal 32P-containing source material, quantitative solution transfers, and a gravimetrically-based dilution; followed by liquid scintillation (LS) spectrometry of the resulting master solution with 3H-standard efficiency tracing using composition-matched LS cocktails. The LS spectrometry utilized a previously-developed method for resolving the always-present 33P impurity. The protocol included provisions for accounting for all possible losses of 32P in the digestion procedure (based on radiochemical tracing experiments), for any unrecovered activity in the remaining source material, and for any residual activity in the solution-transfer and containing vessels. Sections of the TiNi jackets adjacent to the cut-off active seed portions were also assayed for any contained activity. Such destructive assays were required for relating measurements of the absorbed dose spatial distribution for the seeds to theoretic dose modelling and for establishing calibration factors for subsequent non-destructive radionuclidic measurements on the seeds

  7. Preparation and determination of kerma for Iridium 192 sources of low dose rate for brachytherapy

    International Nuclear Information System (INIS)

    The practice of Brachytherapy with Iridium-192 sources of low dose rate (0.4 - 0.8 Gy/h) is a technique used in the treatment of diverse illnesses. in this work the preparation, quality control and calibration are presented in terms of kerma in air of Iridium-192 using as target these recycled Iridium-Platinum wires. The targets were obtained as decayed sources of different radio therapeutical centers in the country and they were characterized by Scanning electron microscopy in order to determine their chemical composition. Subsequently it was developed an experimental design to establish the effect of neutron flux, geometrical array and irradiation time over the activity and percentage of the sources homogeneity. The homogeneity was determined by auto radiography and by Gamma spectroscopy. Once the optimal irradiation conditions were established, it is determined the apparent activity and kerma in air using a well type ionization chamber with traceability to a primary laboratory. Iridium-192 sources were obtained with an average homogeneity 96 %, apparent activity 282.129 ± 0.531 M Bq and kerma in air 0.03200 ± 0.00006 m Gy m/h A. (Author)

  8. Proposal of a postal system for Ir-192 sources calibration used in high dose rate brachytherapy with LiF:Mn:Ti thermoluminescent dosemeters

    International Nuclear Information System (INIS)

    A proposal in order to improve the brachytherapy quality control and to allow postal intercomparison of Ir-192 sources used in high dose rate brachytherapy has been presented. The LiF: Mn: Ti (TLD 100) detector has been selected for such purpose. The experimental array and the TLDs irradiation and calibration techniques, at the treatment units, have been specified in the light of more recent methodology of Ir-192 calibration sources. (Author)

  9. Dosimetric study of a brachytherapy treatment of esophagus with Brazilian 192Ir sources using an anthropomorphic phantom

    International Nuclear Information System (INIS)

    Several radioisotopes are produced at Instituto de Pesquisas Energéticas e Nucleares for the use in medical treatments, including the activation of 192Ir sources. These sources are suitable for brachytherapy treatments, due to their low or high activity, depending on the concentration of 192Ir, easiness to manufacture, small size, stable daughter products and the possibility of re-utilization. They may be used for the treatment of prostate, cervix, head and neck, skin, breast, gallbladder, uterus, vagina, lung, rectum, and eye cancer treatment. In this work, the use of some 192Ir sources was studied for the treatment of esophagus cancer, especially the dose determination of important structures, such as those on the mediastinum. This was carried out utilizing a FASH anthropomorphic phantom and the MCNP5 Monte Carlo code to transport the radiation through matter. It was possible to observe that the doses at lungs, breast, esophagus, thyroid and heart were the highest, which was expected due to their proximity to the source. Therefore, the data are useful to assess the representative dose specific to brachytherapy treatments on the esophagus for radiation protection purposes. - Author-Highlights: • The use of brachytherapy sources was studied for the treatment of esophagus cancer. • FASH anthropomorphic phantom and MCNP5 Monte Carlo code were employed. • The doses at lungs, breast, esophagus, thyroid and heart were the highest. • The data is useful to assess the representative doses of treatments on the esophagus

  10. Monte Carlo characterization of the Gamma-Med Hdr plus Ir-192 brachytherapy source

    International Nuclear Information System (INIS)

    Full text: The MCNP4C Monte Carlo code was used to simulate the dosimetry around the Gamma-Med Hdr Plus iridium-192 brachytherapy source in both air/vacuum and water environments. Dosimetry data in water was calculated and are presented into an away-along table. All dosimetric quantities recommended by the AAPM Task Group 43 report have been also calculated. These quantities are air kerma strength, dose rate constant, radial dose function and anisotropy function. The obtained data are compared to this source reference data, finding results in good agreement with them. In this study, recommendations of the AAPM TG-43U1 report have been followed and comply with the most recent AAPM and ESTRO physics committee recommendations about Monte Carlo techniques. The data in the present study complement published data and can be used as input in the Tps or as benchmark data to verify the results of the treatment planning systems as well as a means of comparison with other datasets from this source. (Author)

  11. Monte Carlo and experimental dosimetric study of the mHDR-v2 brachytherapy source

    Directory of Open Access Journals (Sweden)

    Chandola Rakesh

    2010-01-01

    Full Text Available The conventional treatment planning system (TPS gives analytical calculations with ± 15 to 20% dose, which may lead to over exposure of critical organs or under dose of target. It is to obtain dose distribution parameters of nucletron high dose rate (HDR microselectron v2 (mHDR-v2 192 Ir brachytherapy source by experiment and by calculated study using Monte Carlo (MC EGSnrc code, and to find the similarity between them, and with any past study. To validate data, another MC GEANT4 study done in this work on the same source is also presented. Different software of the computer e.g. paint, excel, etc are employed for preparation of figures and graphs. The measured study of the source was done using an in-air ionization chamber, water phantom, and measurement set-up, while the calculated study was done by modeling the set up of the measured study by using the MC EGSnrc and GEANT4. Mean and probability are used in calculation of average values, and calculation of the uncertainties in result and discussion. The measured and calculated values of dose rate constant, radial dose function, and 2D anisotropy function were found to be in agreement with each other as well as with published data. The results of this study can be used as input to TPS.

  12. Monte Carlo characterization of the Gamma-Med Hdr plus Ir-192 brachytherapy source

    Energy Technology Data Exchange (ETDEWEB)

    Reyes, E.; Sosa, M. A.; Gil V, A. [Universidad de Guanajuato, Division de Ciencias e Ingenierias, Av. Insurgentes 2354, 37150 Leon, Guanajuato (Mexico); Monzon, E., E-mail: eric_1985@fisica.ugto.mx [IMSS, Unidad Medica de Alta Especialidad No. 1, Av. Adolfo Lopez Mateos 1813, 37340 Leon, Guanajuato (Mexico)

    2015-10-15

    Full text: The MCNP4C Monte Carlo code was used to simulate the dosimetry around the Gamma-Med Hdr Plus iridium-192 brachytherapy source in both air/vacuum and water environments. Dosimetry data in water was calculated and are presented into an away-along table. All dosimetric quantities recommended by the AAPM Task Group 43 report have been also calculated. These quantities are air kerma strength, dose rate constant, radial dose function and anisotropy function. The obtained data are compared to this source reference data, finding results in good agreement with them. In this study, recommendations of the AAPM TG-43U1 report have been followed and comply with the most recent AAPM and ESTRO physics committee recommendations about Monte Carlo techniques. The data in the present study complement published data and can be used as input in the Tps or as benchmark data to verify the results of the treatment planning systems as well as a means of comparison with other datasets from this source. (Author)

  13. Quality assurance programme in high dose rate brachytherapy with Iridium-192 source. Recommendations of the French Medical Physicists Society

    International Nuclear Information System (INIS)

    A report on Quality Assurance in High Dose Rate brachytherapy with Iridium-192 source has been prepared by the task group of the Brachytherapy committee of the French Medical Physicists Society. This report provides recommendations on what should be tested, the methods to be used, the test frequencies and the tolerances. The Quality Assurance Programme concerns mainly the Q.A. on the treatment unit, the treatment planning system and the patient procedure. Tolerances and action levels are linked to international recommendations. Safety standards are linked to national legislation and to international recommendations. It is the responsibility of the Institution to verify that the source calibration provided by the manufacturer is correct. The calibration of the Iridium-192 source should be an in-air measurement of air-kerma using an ionization chamber. The recommended tolerance between manufacturer and Institution calibration is 3 %. Quality Control on remote afterloading systems should include consideration of the accuracy and reproducibility of positioning of sources in the applicators. Safety features must also be evaluated regularly and emergency procedures should be tested regularly and posted in a prominent place. After the detailed acceptance tests of dose calculation algorithm, routine checks should be done after software update. An independent dose calculation is recommended before treatment. The recommended agreement with the computer calculation should be within 10%. A written dosimetry report for each brachytherapy procedure is recommended to be inserted in patient charts. The results of all tests should be recorded in a logbook. Fault conditions should be carefully documented

  14. In vivo dosimetry HDR brachytherapy prostate with source CO-60: Results of measures in a point urethra

    International Nuclear Information System (INIS)

    In this study we present and analyze the results of the in vivo dosimetry made a point of urethra with a group of 30 patients treated with brachytherapy prostate high rate with Co-60 source. Taking into account the uncertainties, the results and integration, globally evaluate this system DIV. This DIV system, due to its ease of calibration and use, and provides a relatively simple integration way to avoid serious errors in administering treatment. (Author)

  15. Comparison of calibration procedures for 192Ir high-dose-rate brachytherapy sources

    International Nuclear Information System (INIS)

    Purpose: To compare the efficacy of different calibration procedures for 192Ir high-dose-rate (HDR) brachytherapy sources and to determine their suitability in clinical practice. In addition the manufacturer's calibration is compared with our experimental measurements so that the accuracy of the source strength on the manufacturer certificate which is supplied with each new 192Ir source can be accessed. Methods and Materials: We compared three types of calibration system: well-type chambers (HDR-1000 and SDS), cylindrical phantom, and plate phantom. The total number of measurements we obtained was 365. The number of sources used for the calibration procedure comparison was 20 and the number used for comparison with the manufacturer's calibration was 46. This study was made during the period 1989-1997. Also, Physikalisch-Technische Bundesanstalt (PTB) calibrated one of our sources using their PTB protocol so that the results could be compared with our own. Results: The sensitivity of each system on scattering from the room walls was studied. It was found that different minimum lateral distances from the walls were required for the different systems tested: 15 cm and 25 cm for the well-type chambers, 75 cm for the cylindrical phantom, and 13 cm for the plate phantom. The minimum thickness required to reach phantom scattering saturation for the plate phantom setup is 24 cm. The influence of the applicator material used in the calibration setup was found to be 1.7% for the stainless steel dosimetry applicator compared to the plastic 5F applicator. The accuracy of source positioning within the applicator can lead to dosimetric errors of ±1.2% for the radial distance of 8.0 cm used with both solid phantoms. The change in the response for both well-type chambers was only 0.1% for changes in the source position within ±7.5 mm around the response peak. Good agreement was found between all dosimetry systems included in our study. Taking the HDR-1000 well-type chamber

  16. Overview on the dosimetric uncertainty analysis for photon-emitting brachytherapy sources, in the light of the AAPM Task Group No 138 and GEC-ESTRO report

    International Nuclear Information System (INIS)

    In 2011, the American Association of Physicists in Medicine (AAPM) and the Groupe Europeen de Curietherapie-European Society for Radiotherapy and Oncology (GEC-ESTRO) published a report pertaining to uncertainties in brachytherapy single-source dosimetry preceding clinical use. The International Organization for Standardization's Guide to the Expression of Uncertainty in Measurement and Technical Note 1297 by the National Institute of Standards and Technology are taken as reference standards for uncertainty formalism. Uncertainties involved in measurements or Monte Carlo methods to estimate brachytherapy dose distributions are provided with discussion of the components intrinsic to the overall dosimetric assessment. The uncertainty propagation from the primary calibration standard through transfer to the clinic for air-kerma strength is given with uncertainties in each of the brachytherapy dosimetry parameters of the AAPM TG-43 dose-calculation formalism. For low-energy and high-energy brachytherapy sources of low dose-rate and high dose-rate, a combined dosimetric uncertainty ≤5% (k = 1) is estimated, which is consistent with prior literature estimates. Recommendations are provided for clinical medical physicists, dosimetry investigators, and manufacturers of brachytherapy sources and treatment planning systems. These recommendations reflect the guidance of the AAPM and GEC-ESTRO for their members, and may also be used as guidance to manufacturers and regulatory agencies in developing good manufacturing practices for conventional brachytherapy sources used in routine clinical treatments. (authors)

  17. HDR neutron brachytherapy for cervix carcinoma in Lithuania

    International Nuclear Information System (INIS)

    Between 1988 and December 1995, a total of 285 patients with stage I-17, with stage II-157, with stage III-104 and stage IV-7 carcinoma of the cervix were treated with a combination of external beam radiation or surgery and HDR brachytherapy. The dose prescription for HDR brachytherapy was point A. The goals of combined radiation therapy were to deliver a total dose of 60.5-68.5 Gy to point A and 53-58 Gy to the pelvic lymph nodes (point B) or 14 Gy-eq to point A in case of preoperative brachytherapy. Dosimetric planning was performed in Gray- equivalents by the use of PC-based computer programme. Relative biological effectiveness of the Cf-252 neutrons was physical gamma and neutron dose rate dependent. Most of the insertions were performed weekly when dose per fraction was 8-10 Gy or 2 insertions were done in one week at lower fractions. The median follow-up for the various stages of disease ranged from 0.5 to 6.5 year. Treatment results, acute and late toxicity will be discussed

  18. Influences of spherical phantom heterogeneities on dosimetric charactristics of miniature electronic brachytherapy X-ray sources: Monte Carlo study

    International Nuclear Information System (INIS)

    Dose calculations in current brachytherapy treatment planning systems (TPS) are commonly based on TG‐43U1 formalism. These TPS are obtained by superposition principle of single‐source dosimetric parameters in liquid water, neglecting the effects of tissue heterogeneity. In this work, the sensitivity of the TG-43U1 based radial dose function (g(r)) of Miniature Electronic Brachytherapy X-ray Sources (MEBXS) to bone-heterogeneity was examined. To quantify the heterogeneity effects for g(r), a series of Monte Carlo (MC) based radiation transport simulations at the center of homogeneous and heterogeneous spherical phantoms were performed using the MCNP5 code. The ratio of the g(r) in the heterogeneius phantom to the uniform soft tisuue phantom as a function of the bone thickness was determined. These results indicated that for 40 keV beam, the maximum ratios for thicknesses of 1 cm and 2 cm were 3.36 and 3.27, respectively. These values changed to 4.28 and 4.06, for 60 keV beam, respectively. Introduction of 0.5 cm or 1 cm red marrow, into the interior of the cortical bone changed the maximum variations to, 3.54, and 3.57 for 40 keV, and 4.28, and 4.25, for 60 keV, respectively. - Highlights: • Monte Carlo simulation was used to model the bone heterogeneity for Electronic Brachytherapy. • Variation of the TG-43U1 radial dose function is dependent to bone thickness and is higher than the water phantom. • For skin cancer treatment in sites which is close immediately to the bone, the bone damage is higher than the skin tissue. • To spare the bone in skin treatment (i.e. scalp, legs) bone heterogeneity effect should be applied to the electronic brachytherapy dosimetric

  19. A novel optical calorimetry dosimetry approach applied to an HDR Brachytherapy source

    International Nuclear Information System (INIS)

    The technique of Digital Holographic Interferometry (DHI) is applied to the measurement of radiation absorbed dose distribution in water. An optical interferometer has been developed that captures the small variations in the refractive index of water due to the radiation induced temperature increase ΔT. The absorbed dose D is then determined with high temporal and spatial resolution using the calorimetric relation D=cΔT (where c is the specific heat capacity of water). The method is capable of time resolving 3D spatial calorimetry. As a proof-of-principle of the approach, a prototype DHI dosimeter was applied to the measurement of absorbed dose from a High Dose Rate (HDR) Brachytherapy source. Initial results are in agreement with modelled doses from the Brachyvision treatment planning system, demonstrating the viability of the system for high dose rate applications. Future work will focus on applying corrections for heat diffusion and geometric effects. The method has potential to contribute to the dosimetry of diverse high dose rate applications which require high spatial resolution such as microbeam radiotherapy (MRT) or small field proton beam dosimetry but may potentially also be useful for interface dosimetry.

  20. Fabrication of Miniature Titanium Capsule for Brachytherapy Sources Using Tungsten Inert Gas Method

    International Nuclear Information System (INIS)

    The capsules containing radioactive materials as brachytherapy sources are used for implanting into some target organs for malignant disorders treatments, such as prostate, eyes, and brain cancers. The conventional method for sealing the tubes is to weld them using a laser beam which is now a part of tube melting methods (self welding). The purpose of this study was to seal miniature titanium tubes containing radioactive materials in the form of capsules. This study introduced a new method based on melting process. A piece of commercially pure titanium grade 2 in the form of disk was used for the experiment. The sample was melted at the top of the tube by a Tungsten Inert Gas welding device for a short time duration. After completion of the melting, the disk in the form of a drop was mixed with a small part of it and both were solidified and hence closed the tube. We evaluated the tubes for the metallurgical properties and seal process which took place by Tungsten Inert Gas in different zones, including the heat affected zone, fusion zone, and interface of the joint of the drop to the tube. Finally, the produced samples were tested according to the ISO2919 and ISO9978 and the results confirmed the Disk and Tungsten Inert Gas procedure.

  1. Direct measurement of instantaneous source speed for a HDR brachytherapy unit using an optical fiber based detector

    Energy Technology Data Exchange (ETDEWEB)

    Minamisawa, R. A.; Rubo, R. A.; Seraide, R. M.; Rocha, J. R. O.; Almeida, A. [Department of Physics and Mathematics, FFCLRP, University of Sao Paulo, 14040-901, Ribeirao Preto-SP (Brazil); INRAD, Medical School - University of Sao Paulo, Clinical Hospital (HCUSP), 05403-001, Sao Paulo-SP (Brazil); CAISM Radiotherapy Service, CEB, State University of Campinas, 13083-881, Campinas-SP (Brazil); Department of Physics and Mathematics, FFCLRP, University of Sao Paulo, 14040-901, Ribeirao Preto-SP (Brazil)

    2010-10-15

    Purpose: Several attempts to determine the transit time of a high dose rate (HDR) brachytherapy unit have been reported in the literature with controversial results. The determination of the source speed is necessary to accurately calculate the transient dose in brachytherapy treatments. In these studies, only the average speed of the source was measured as a parameter for transit dose calculation, which does not account for the realistic movement of the source, and is therefore inaccurate for numerical simulations. The purpose of this work is to report the implementation and technical design of an optical fiber based detector to directly measure the instantaneous speed profile of a {sup 192}Ir source in a Nucletron HDR brachytherapy unit. Methods: To accomplish this task, we have developed a setup that uses the Cerenkov light induced in optical fibers as a detection signal for the radiation source moving inside the HDR catheter. As the {sup 192}Ir source travels between two optical fibers with known distance, the threshold of the induced signals are used to extract the transit time and thus the velocity. The high resolution of the detector enables the measurement of the transit time at short separation distance of the fibers, providing the instantaneous speed. Results: Accurate and high resolution speed profiles of the {sup 192}Ir radiation source traveling from the safe to the end of the catheter and between dwell positions are presented. The maximum and minimum velocities of the source were found to be 52.0{+-}1.0 and 17.3{+-}1.2 cm/s. The authors demonstrate that the radiation source follows a uniformly accelerated linear motion with acceleration of |a|=113 cm/s{sup 2}. In addition, the authors compare the average speed measured using the optical fiber detector to those obtained in the literature, showing deviation up to 265%. Conclusions: To the best of the authors' knowledge, the authors directly measured for the first time the instantaneous speed

  2. Direct measurement of instantaneous source speed for a HDR brachytherapy unit using an optical fiber based detector

    International Nuclear Information System (INIS)

    Purpose: Several attempts to determine the transit time of a high dose rate (HDR) brachytherapy unit have been reported in the literature with controversial results. The determination of the source speed is necessary to accurately calculate the transient dose in brachytherapy treatments. In these studies, only the average speed of the source was measured as a parameter for transit dose calculation, which does not account for the realistic movement of the source, and is therefore inaccurate for numerical simulations. The purpose of this work is to report the implementation and technical design of an optical fiber based detector to directly measure the instantaneous speed profile of a 192Ir source in a Nucletron HDR brachytherapy unit. Methods: To accomplish this task, we have developed a setup that uses the Cerenkov light induced in optical fibers as a detection signal for the radiation source moving inside the HDR catheter. As the 192Ir source travels between two optical fibers with known distance, the threshold of the induced signals are used to extract the transit time and thus the velocity. The high resolution of the detector enables the measurement of the transit time at short separation distance of the fibers, providing the instantaneous speed. Results: Accurate and high resolution speed profiles of the 192Ir radiation source traveling from the safe to the end of the catheter and between dwell positions are presented. The maximum and minimum velocities of the source were found to be 52.0±1.0 and 17.3±1.2 cm/s. The authors demonstrate that the radiation source follows a uniformly accelerated linear motion with acceleration of |a|=113 cm/s2. In addition, the authors compare the average speed measured using the optical fiber detector to those obtained in the literature, showing deviation up to 265%. Conclusions: To the best of the authors' knowledge, the authors directly measured for the first time the instantaneous speed profile of a radiation source in a HDR

  3. Dependence with air density of the response of the PTW SourceCheck ionization chamber for low energy brachytherapy sources

    International Nuclear Information System (INIS)

    Purpose: Air-communicating well ionization chambers are commonly used to assess air kerma strength of sources used in brachytherapy. The signal produced is supposed to be proportional to the air density within the chamber and, therefore, a density-independent air kerma strength is obtained when the measurement is corrected to standard atmospheric conditions using the usual temperature and pressure correction factor. Nevertheless, when assessing low energy sources, the ionization chambers may not fulfill that condition and a residual density dependence still remains after correction. In this work, the authors examined the behavior of the PTW 34051 SourceCheck ionization chamber when measuring the air kerma strength of 125I seeds.Methods: Four different SourceCheck chambers were analyzed. With each one of them, two series of measurements of the air kerma strength for 125I selectSeedTM brachytherapy sources were performed inside a pressure chamber and varying the pressure in a range from 747 to 1040 hPa (560 to 780 mm Hg). The temperature and relative humidity were kept basically constant. An analogous experiment was performed by taking measurements at different altitudes above sea level.Results: Contrary to other well-known ionization chambers, like the HDR1000 PLUS, in which the temperature-pressure correction factor overcorrects the measurements, in the SourceCheck ionization chamber they are undercorrected. At a typical atmospheric situation of 933 hPa (700 mm Hg) and 20 °C, this undercorrection turns out to be 1.5%. Corrected measurements show a residual linear dependence on the density and, as a consequence, an additional density dependent correction must be applied. The slope of this residual linear density dependence is different for each SourceCheck chamber investigated. The results obtained by taking measurements at different altitudes are compatible with those obtained with the pressure chamber.Conclusions: Variations of the altitude and changes in the

  4. Dependence with air density of the response of the PTW SourceCheck ionization chamber for low energy brachytherapy sources

    Energy Technology Data Exchange (ETDEWEB)

    Tornero-López, Ana M.; Guirado, Damián; Ruiz-Arrebola, Samuel [Servicio de Radiofísica y Protección Radiológica, Hospital Universitario San Cecilio, E-18012 Granada (Spain); Perez-Calatayud, Jose [Servicio de Radioterapia, Unidad de Radiofísica, Hospital Universitario y Politécnico La Fe, E-46026 Valencia (Spain); Simancas, Fernando; Lallena, Antonio M. [Departamento de Física Atómica, Molecular y Nuclear, Universidad de Granada, E-18071 Granada (Spain); Gazdic-Santic, Maja [Department of Medical Physics and Radiation Safety, Clinical Centre of Sarajevo University, 71000 Sarajevo (Bosnia and Herzegovina)

    2013-12-15

    Purpose: Air-communicating well ionization chambers are commonly used to assess air kerma strength of sources used in brachytherapy. The signal produced is supposed to be proportional to the air density within the chamber and, therefore, a density-independent air kerma strength is obtained when the measurement is corrected to standard atmospheric conditions using the usual temperature and pressure correction factor. Nevertheless, when assessing low energy sources, the ionization chambers may not fulfill that condition and a residual density dependence still remains after correction. In this work, the authors examined the behavior of the PTW 34051 SourceCheck ionization chamber when measuring the air kerma strength of {sup 125}I seeds.Methods: Four different SourceCheck chambers were analyzed. With each one of them, two series of measurements of the air kerma strength for {sup 125}I selectSeed{sup TM} brachytherapy sources were performed inside a pressure chamber and varying the pressure in a range from 747 to 1040 hPa (560 to 780 mm Hg). The temperature and relative humidity were kept basically constant. An analogous experiment was performed by taking measurements at different altitudes above sea level.Results: Contrary to other well-known ionization chambers, like the HDR1000 PLUS, in which the temperature-pressure correction factor overcorrects the measurements, in the SourceCheck ionization chamber they are undercorrected. At a typical atmospheric situation of 933 hPa (700 mm Hg) and 20 °C, this undercorrection turns out to be 1.5%. Corrected measurements show a residual linear dependence on the density and, as a consequence, an additional density dependent correction must be applied. The slope of this residual linear density dependence is different for each SourceCheck chamber investigated. The results obtained by taking measurements at different altitudes are compatible with those obtained with the pressure chamber.Conclusions: Variations of the altitude and

  5. Automation system for quality control in manufacture of iodine-125 sealed sources used in brachytherapy

    Energy Technology Data Exchange (ETDEWEB)

    Somessari, Samir L.; Feher, Anselmo; Sprenger, Francisco E.; Rostellato, Maria E.C.M.; Moura, Joao A.; Costa, Osvaldo L.; Calvo, Wilson A.P., E-mail: somessar@ipen.b, E-mail: afeher@ipen.b, E-mail: sprenger@ipen.b, E-mail: elisaros@ipen.b, E-mail: olcosta@ipen.b, E-mail: wapcalvo@ipen.b [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil)

    2011-07-01

    The objective of this work is to develop an automation system for Quality Control in the production of Iodine-125 sealed sources, after undergoing the process of laser beam welding. These sources, also known as Iodine-125 seeds are used, successfully, in the treatment of cancer by brachytherapy, with low-dose rates. Each small seed is composed of a welded titanium capsule with 0.8 mm diameter and 4.5 mm in length, containing Iodine-125 adsorbed on an internal silver wire. The seeds are implanted in the human prostate to irradiate the tumor and treat the cancerous cells. The technology to automate the quality control system in the manufacture of Iodine-125 seeds consists in developing and associate mechanical parts, electronic components and pneumatic circuits to control machines and processes. The automation technology for Iodine-125 seed production developed in this work employs programmable logic controller, step motors, drivers of control, electrical-electronic interfaces, photoelectric sensors, interfaces of communication and software development. Industrial automation plays an important role in the production of Iodine-125 seeds, with higher productivity and high standard of quality, facilitating the implementation and operation of processes with good manufacturing practices. Nowadays, the Radiation Technology Center at IPEN-CNEN/SP imports and distributes 36,000 Iodine-125 seeds per year for clinics and hospitals in the whole country. However, the Brazilian potential market is of 8,000 Iodine-125 seeds per month. Therefore, the local production of these radioactive seeds has become a priority for the Institute, aiming to reduce the price and increase the supply to the population in Brazil. (author)

  6. Automation system for quality control in manufacture of iodine-125 sealed sources used in brachytherapy

    International Nuclear Information System (INIS)

    The objective of this work is to develop an automation system for Quality Control in the production of Iodine-125 sealed sources, after undergoing the process of laser beam welding. These sources, also known as Iodine-125 seeds are used, successfully, in the treatment of cancer by brachytherapy, with low-dose rates. Each small seed is composed of a welded titanium capsule with 0.8 mm diameter and 4.5 mm in length, containing Iodine-125 adsorbed on an internal silver wire. The seeds are implanted in the human prostate to irradiate the tumor and treat the cancerous cells. The technology to automate the quality control system in the manufacture of Iodine-125 seeds consists in developing and associate mechanical parts, electronic components and pneumatic circuits to control machines and processes. The automation technology for Iodine-125 seed production developed in this work employs programmable logic controller, step motors, drivers of control, electrical-electronic interfaces, photoelectric sensors, interfaces of communication and software development. Industrial automation plays an important role in the production of Iodine-125 seeds, with higher productivity and high standard of quality, facilitating the implementation and operation of processes with good manufacturing practices. Nowadays, the Radiation Technology Center at IPEN-CNEN/SP imports and distributes 36,000 Iodine-125 seeds per year for clinics and hospitals in the whole country. However, the Brazilian potential market is of 8,000 Iodine-125 seeds per month. Therefore, the local production of these radioactive seeds has become a priority for the Institute, aiming to reduce the price and increase the supply to the population in Brazil. (author)

  7. Estimation of distance error by fuzzy set theory required for strength determination of HDR 192Ir brachytherapy sources

    International Nuclear Information System (INIS)

    Verification of the strength of high dose rate (HDR) 192Ir brachytherapy sources on receipt from the vendor is an important component of institutional quality assurance program. Either reference air-kerma rate (RAKR) or air-kerma strength (AKS) is the recommended quantity to specify the strength of gamma-emitting brachytherapy sources. The use of Farmer-type cylindrical ionization chamber of sensitive volume 0.6 cm3 is one of the recommended methods for measuring RAKR of HDR 192Ir brachytherapy sources. While using the cylindrical chamber method, it is required to determine the positioning error of the ionization chamber with respect to the source which is called the distance error. An attempt has been made to apply the fuzzy set theory to estimate the subjective uncertainty associated with the distance error. A simplified approach of applying this fuzzy set theory has been proposed in the quantification of uncertainty associated with the distance error. In order to express the uncertainty in the framework of fuzzy sets, the uncertainty index was estimated and was found to be within 2.5%, which further indicates that the possibility of error in measuring such distance may be of this order. It is observed that the relative distance li estimated by analytical method and fuzzy set theoretic approach are consistent with each other. The crisp values of li estimated using analytical method lie within the bounds computed using fuzzy set theory. This indicates that li values estimated using analytical methods are within 2.5% uncertainty. This value of uncertainty in distance measurement should be incorporated in the uncertainty budget, while estimating the expanded uncertainty in HDR 192Ir source strength measurement. (author)

  8. Estimation of distance error by fuzzy set theory required for strength determination of HDR (192)Ir brachytherapy sources.

    Science.gov (United States)

    Kumar, Sudhir; Datta, D; Sharma, S D; Chourasiya, G; Babu, D A R; Sharma, D N

    2014-04-01

    Verification of the strength of high dose rate (HDR) (192)Ir brachytherapy sources on receipt from the vendor is an important component of institutional quality assurance program. Either reference air-kerma rate (RAKR) or air-kerma strength (AKS) is the recommended quantity to specify the strength of gamma-emitting brachytherapy sources. The use of Farmer-type cylindrical ionization chamber of sensitive volume 0.6 cm(3) is one of the recommended methods for measuring RAKR of HDR (192)Ir brachytherapy sources. While using the cylindrical chamber method, it is required to determine the positioning error of the ionization chamber with respect to the source which is called the distance error. An attempt has been made to apply the fuzzy set theory to estimate the subjective uncertainty associated with the distance error. A simplified approach of applying this fuzzy set theory has been proposed in the quantification of uncertainty associated with the distance error. In order to express the uncertainty in the framework of fuzzy sets, the uncertainty index was estimated and was found to be within 2.5%, which further indicates that the possibility of error in measuring such distance may be of this order. It is observed that the relative distance li estimated by analytical method and fuzzy set theoretic approach are consistent with each other. The crisp values of li estimated using analytical method lie within the bounds computed using fuzzy set theory. This indicates that li values estimated using analytical methods are within 2.5% uncertainty. This value of uncertainty in distance measurement should be incorporated in the uncertainty budget, while estimating the expanded uncertainty in HDR (192)Ir source strength measurement. PMID:24872605

  9. Estimation of distance error by fuzzy set theory required for strength determination of HDR 192Ir brachytherapy sources

    Science.gov (United States)

    Kumar, Sudhir; Datta, D.; Sharma, S. D.; Chourasiya, G.; Babu, D. A. R.; Sharma, D. N.

    2014-01-01

    Verification of the strength of high dose rate (HDR) 192Ir brachytherapy sources on receipt from the vendor is an important component of institutional quality assurance program. Either reference air-kerma rate (RAKR) or air-kerma strength (AKS) is the recommended quantity to specify the strength of gamma-emitting brachytherapy sources. The use of Farmer-type cylindrical ionization chamber of sensitive volume 0.6 cm3 is one of the recommended methods for measuring RAKR of HDR 192Ir brachytherapy sources. While using the cylindrical chamber method, it is required to determine the positioning error of the ionization chamber with respect to the source which is called the distance error. An attempt has been made to apply the fuzzy set theory to estimate the subjective uncertainty associated with the distance error. A simplified approach of applying this fuzzy set theory has been proposed in the quantification of uncertainty associated with the distance error. In order to express the uncertainty in the framework of fuzzy sets, the uncertainty index was estimated and was found to be within 2.5%, which further indicates that the possibility of error in measuring such distance may be of this order. It is observed that the relative distance li estimated by analytical method and fuzzy set theoretic approach are consistent with each other. The crisp values of li estimated using analytical method lie within the bounds computed using fuzzy set theory. This indicates that li values estimated using analytical methods are within 2.5% uncertainty. This value of uncertainty in distance measurement should be incorporated in the uncertainty budget, while estimating the expanded uncertainty in HDR 192Ir source strength measurement. PMID:24872605

  10. Study of dose distributions in voxel phantoms for brachytherapy sources using the GEANT4 Monte Carlo toolkit

    International Nuclear Information System (INIS)

    This work studies the effects of corrections in the calculation of dose distribution for brachytherapy sources when they are inserted in a male human voxel phantom. The sources studied here are the Best Industries 125I 2301 model for low dose rate and the Amersham Buchler G0814 model 192Ir seed for high dose rate, in the simulation of prostate treatments. The presence of organs around the interest point scatters radiation in a different form than a water cube, the situation that is usually configured in these calculations. The insertion of the sources in an anthropomorphic phantom brings results closer to the real situation. The chosen phantom was the head and torso voxel phantom created by Zubal. The Geant4 Monte Carlo toolkit was used to simulate the radiation transportation along the source shielding and the human organs of the voxel phantom. After inserting the source in the phantom, the energy deposition in each voxel is computed, allowing the construction of isodose curves. The source insertion in the anthropomorphic phantom aims also at a further knowledge about the brachytherapy treatment planning and additional information such as the target volume dose and in neighbor organs, data that will be useful for medical staff working with this technique. (author)

  11. Determination of the intrinsic energy dependence of LiF:Mg,Ti thermoluminescent dosimeters for 125I and 103Pd brachytherapy sources relative to 60Co

    International Nuclear Information System (INIS)

    Purpose: To determine the intrinsic energy dependence of LiF:Mg,Ti thermoluminescent dosimeters (TLD-100) for 125I and 103Pd brachytherapy sources relative to 60Co. Methods: LiF:Mg,Ti TLDs were irradiated with low-energy brachytherapy sources and with a 60Co teletherapy source. The brachytherapy sources measured were the Best 2301 125I seed, the OncoSeed 6711 125I seed, and the Best 2335 103Pd seed. The TLD light output per measured air-kerma strength was determined for the brachytherapy source irradiations, and the TLD light output per air kerma was determined for the 60Co irradiations. Monte Carlo (MC) simulations were used to calculate the dose-to-TLD rate per air-kerma strength for the brachytherapy source irradiations and the dose to TLD per air kerma for the 60Co irradiations. The measured and MC-calculated results for all irradiations were used to determine the TLD intrinsic energy dependence for 125I and 103Pd relative to 60Co. Results: The relative TLD intrinsic energy dependences (relative to 60Co) and associated uncertainties (k = 1) were determined to be 0.883 ± 1.3%, 0.870 ± 1.4%, and 0.871 ± 1.5% for the Best 2301 seed, OncoSeed 6711 seed, and Best 2335 seed, respectively. Conclusions: The intrinsic energy dependence of TLD-100 is dependent on photon energy, exhibiting changes of 13%–15% for 125I and 103Pd sources relative to 60Co. TLD measurements of absolute dose around 125I and 103Pd brachytherapy sources should explicitly account for the relative TLD intrinsic energy dependence in order to improve dosimetric accuracy

  12. Investigation of Dosimetric Parameters of $^{192}$Ir MicroSelectron v2 HDR Brachytherapy Source Using EGSnrc Monte Carlo Code

    CERN Document Server

    Naeem, Hamza; Zheng, Huaqing; Cao, Ruifen; Pei, Xi; Hu, Liqin; Wu, Yican

    2016-01-01

    The $^{192}$Ir sources are widely used for high dose rate (HDR) brachytherapy treatments. The aim of this study is to simulate $^{192}$Ir MicroSelectron v2 HDR brachytherapy source and calculate the air kerma strength, dose rate constant, radial dose function and anisotropy function established in the updated AAPM Task Group 43 protocol. The EGSnrc Monte Carlo (MC) code package is used to calculate these dosimetric parameters, including dose contribution from secondary electron source and also contribution of bremsstrahlung photons to air kerma strength. The Air kerma strength, dose rate constant and radial dose function while anisotropy functions for the distance greater than 0.5 cm away from the source center are in good agreement with previous published studies. Obtained value from MC simulation for air kerma strength is $9.762\\times 10^{-8} \\textrm{UBq}^{-1}$and dose rate constant is $1.108\\pm 0.13\\%\\textrm{cGyh}^{-1} \\textrm{U}^{-1}$.

  13. Interstitial brachytherapy dosimetry update

    International Nuclear Information System (INIS)

    In March 2004, the American Association of Physicists in Medicine (AAPM) published an update to the AAPM Task Group No. 43 Report (TG-43) which was initially published in 1995. This update was pursued primarily due to the marked increase in permanent implantation of low-energy photon-emitting brachytherapy sources in the United States over the past decade, and clinical rationale for the need of accurate dosimetry in the implementation of interstitial brachytherapy. Additionally, there were substantial improvements in the brachytherapy dosimetry formalism, accuracy of related parameters and methods for determining these parameters. With salient background, these improvements are discussed in the context of radiation dosimetry. As an example, the impact of this update on the administered dose is assessed for the model 200 103Pd brachytherapy source. (authors)

  14. Comparison of TG-43 dosimetric parameters of brachytherapy sources obtained by three different versions of MCNP codes.

    Science.gov (United States)

    Zaker, Neda; Zehtabian, Mehdi; Sina, Sedigheh; Koontz, Craig; S Meigooni, Ali

    2016-01-01

    Monte Carlo simulations are widely used for calculation of the dosimetric param-eters of brachytherapy sources. MCNP4C2, MCNP5, MCNPX, EGS4, EGSnrc, PTRAN, and GEANT4 are among the most commonly used codes in this field. Each of these codes utilizes a cross-sectional library for the purpose of simulat-ing different elements and materials with complex chemical compositions. The accuracies of the final outcomes of these simulations are very sensitive to the accuracies of the cross-sectional libraries. Several investigators have shown that inaccuracies of some of the cross section files have led to errors in 125I and 103Pd parameters. The purpose of this study is to compare the dosimetric parameters of sample brachytherapy sources, calculated with three different versions of the MCNP code - MCNP4C, MCNP5, and MCNPX. In these simulations for each source type, the source and phantom geometries, as well as the number of the photons, were kept identical, thus eliminating the possible uncertainties. The results of these investigations indicate that for low-energy sources such as 125I and 103Pd there are discrepancies in gL(r) values. Discrepancies up to 21.7% and 28% are observed between MCNP4C and other codes at a distance of 6 cm for 103Pd and 10 cm for 125I from the source, respectively. However, for higher energy sources, the discrepancies in gL(r) values are less than 1.1% for 192Ir and less than 1.2% for 137Cs between the three codes. PMID:27074460

  15. Dosimetric prerequisites for routine clinical use of photon emitting brachytherapy sources with average energy higher than 50 kev

    International Nuclear Information System (INIS)

    This paper presents the recommendations of the American Association of Physicists in Medicine (AAPM) and the European Society for Therapeutic Radiology and Oncology (ESTRO) on the dosimetric parameters to be characterized, and dosimetric studies to be performed to obtain them, for brachytherapy sources with average energy higher than 50 keV that are intended for routine clinical use. In addition, this document makes recommendations on procedures to be used to maintain vendor source strength calibration accuracy. These recommendations reflect the guidance of the AAPM and the ESTRO for its members, and may also be used as guidance to vendors and regulatory agencies in developing good manufacturing practices for sources used in routine clinical treatments

  16. Implementation of GaN based real-time source position monitoring in HDR brachytherapy

    International Nuclear Information System (INIS)

    For High Dose Rate (HDR) brachytherapy Quality Assurance (QA), we propose a seed position verification method by using two GaN dosimetric probes integrated in an instrumented phantom. As dose rate measured from one probe is related to the seed distance, seed position inside catheter can be determined. The proposed two-probe method extends measureable range and improves accuracy in comparison with the use of one single probe. One instrumented phantom implementing the method was designed, fabricated and tested in clinical conditions. The measureable range of the two-probe method is 105 mm compared to 36 mm using single probe. The validity of the method was experimentally verified. - Highlights: • A simple brachytherapy QA phantom has been instrumented. • Dwell positions have been estimated according to measured dose rate by GaN probes. • Measured dose rate shows 1% average deviation from calculated results. • Determined dwell position precision and measureable range was studied

  17. A comparison of the relative biological effectiveness of low energy electronic brachytherapy sources in breast tissue: a Monte Carlo study

    Science.gov (United States)

    White, Shane A.; Reniers, Brigitte; de Jong, Evelyn E. C.; Rusch, Thomas; Verhaegen, Frank

    2016-01-01

    Electronic brachytherapy sources use low energy photons to treat the tumor bed during or after breast-conserving surgery. The relative biological effectiveness of two electronic brachytherapy sources was explored to determine if spectral differences due to source design influenced radiation quality and if radiation quality decreased with distance in the breast. The RBE was calculated through the number of DNA double strand breaks (RBEDSB) using the Monte Carlo damage simulator (MCDS) in combination with other Monte Carlo electron/photon spectrum calculations. 50kVp photons from the Intrabeam (Carl Zeiss Surgical) and Axxent (Xoft) through 40-mm spherical applicators were simulated to account for applicator and tissue attenuation in a variety of breast tissue compositions. 40kVp Axxent photons were also simulated. Secondary electrons (known to be responsible for most DNA damage) spectra at different distance were inputted into MCDS to calculate the RBEDSB. All RBEDSB used a cobalt-60 reference. RBEDSB data was combined with corresponding average photon spectrum energy for the Axxent and applied to model-based average photon energy distributions to produce an RBEDSB map of an accelerated partial breast irradiation (APBI) patient. Both Axxent and Intrabeam 50kVp spectra were shown to have a comparable RBEDSB of between 1.4 and 1.6 at all distances in spite of progressive beam hardening. The Axxent 40kVp also demonstrated a similar RBEDSB at distances. Most RBEDSB variability was dependent on the tissue type as was seen in rib (RBEDSB  ≈  1.4), gland (≈1.55), adipose (≈1.59), skin (≈1.52) and lung (≈1.50). RBEDSB variability between both sources was within 2%. A correlation was shown between RBEDSB and average photon energy and used to produce an RBEDSB map of a dose distribution in an APBI patient dataset. Radiation quality is very similar between electronic brachytherapy sources studied. No significant reductions in RBEDSB were observed with

  18. A fibre optic scintillator dosemeter for absorbed dose measurements of low-energy X-ray-emitting brachytherapy sources

    International Nuclear Information System (INIS)

    A newly developed dosemeter using a 0.5 mm diameter x 0.5 mm thick cylindrical plastic scintillator coupled to the end of a fibre optic cable is capable of measuring the absorbed dose rate in water around low-activity, low-energy X-ray emitters typically used in prostate brachytherapy. Recent tests of this dosemeter showed that it is possible to measure the dose rate as a function of distance in water from 2 to 30 mm of a 103Pd source of air-kerma strength 3.4 U (1 U = 1 μGy m2h-1), or 97 MBq (2.6 mCi) apparent activity, with good signal-to-noise ratio. The signal-to-noise ratio is only dependent on the integration time and background subtraction. The detector volume is enclosed in optically opaque, nearly water-equivalent materials so that there is no polar response other than that due to the shape of the scintillator volume chosen, in this case cylindrical. The absorbed dose rate very close to commercial brachytherapy sources can be mapped in an automated water phantom, providing a 3-D dose distribution with sub-millimeter spatial resolution. The sensitive volume of the detector is 0.5 mm from the end of the optically opaque waterproof housing, enabling measurements at very close distances to sources. The sensitive detector electronics allow the measurement of very low dose rates, as exist at centimeter distances from these sources. The detector is also applicable to mapping dose distributions from more complex source geometries such as eye applicators for treating macular degeneration. (authors)

  19. The non-uniformity correction factor for the cylindrical ionization chambers in dosimetry of an HDR 192Ir brachytherapy source

    Directory of Open Access Journals (Sweden)

    Majumdar Bishnu

    2006-01-01

    Full Text Available The aim of this study is to derive the non-uniformity correction factor for the two therapy ionization chambers for the dose measurement near the brachytherapy source. The two ionization chambers of 0.6 cc and 0.1 cc volume were used. The measurement in air was performed for distances between 0.8 cm and 20 cm from the source in specially designed measurement jig. The non-uniformity correction factors were derived from the measured values. The experimentally derived factors were compared with the theoretically calculated non-uniformity correction factors and a close agreement was found between these two studies. The experimentally derived non-uniformity correction factor supports the anisotropic theory.

  20. Verification and analysis of the positioning of a source of brachytherapy high dose within an applicator gynecological interstitial fletcher Utrecht TC/RM

    International Nuclear Information System (INIS)

    Applicators are guides that circulate and are located within the patient brachytherapy sources. Applicators can suffer mechanical deformations due to processes of sterilization or shock, which may result in that the source do not place within these very precise and coincides with the planned. In these cases the planned treatment deviate actually managed. The object of this study is to verify that the position of the source into the dispenser coincides with the planned position, with a procedure that is described. (Author)

  1. Determination of surface dose rate of indigenous 32P patch brachytherapy source by experimental and Monte Carlo methods

    International Nuclear Information System (INIS)

    Isotope production and Application Division of Bhabha Atomic Research Center developed 32P patch sources for treatment of superficial tumors. Surface dose rate of a newly developed 32P patch source of nominal diameter 25 mm was measured experimentally using standard extrapolation ionization chamber and Gafchromic EBT film. Monte Carlo model of the 32P patch source along with the extrapolation chamber was also developed to estimate the surface dose rates from these sources. The surface dose rates to tissue (cGy/min) measured using extrapolation chamber and radiochromic films are 82.03±4.18 (k=2) and 79.13±2.53 (k=2) respectively. The two values of the surface dose rates measured using the two independent experimental methods are in good agreement to each other within a variation of 3.5%. The surface dose rate to tissue (cGy/min) estimated using the MCNP Monte Carlo code works out to be 77.78±1.16 (k=2). The maximum deviation between the surface dose rates to tissue obtained by Monte Carlo and the extrapolation chamber method is 5.2% whereas the difference between the surface dose rates obtained by radiochromic film measurement and the Monte Carlo simulation is 1.7%. The three values of the surface dose rates of the 32P patch source obtained by three independent methods are in good agreement to one another within the uncertainties associated with their measurements and calculation. This work has demonstrated that MCNP based electron transport simulations are accurate enough for determining the dosimetry parameters of the indigenously developed 32P patch sources for contact brachytherapy applications. - Highlights: • Surface dose rates of 25 mm nominal diameter newly developed 32P patch sources were measured experimentally using extrapolation chamber and Gafchromic EBT2 film. Monte Carlo model of the 32P patch source along with the extrapolation chamber was also developed. • The surface dose rates to tissue (cGy/min) measured using extrapolation chamber and

  2. Calibration of photon and beta ray sources used in brachytherapy. Guidelines on standardized procedures at Secondary Standards Dosimetry Laboratories (SSDLs) and hospitals

    International Nuclear Information System (INIS)

    It has generally been recognized that international harmonization in radiotherapy dosimetry is essential. Consequently, the IAEA has given much effort to this, for example by publishing a number of reports in the Technical Reports Series (TRS) for external beam dosimetry, most notably TRS-277 and more recently TRS-398. Both of these reports describe in detail the steps to be taken for absorbed dose determination in water and they are often referred to as 'dosimetry protocols'. Similar to TRS-277, it is expected that TRS-398 will be adopted or used as a model by a large number of countries as their national protocol. In 1996, the IAEA established a calibration service for low dose rate (LDR) 137 Cs brachytherapy sources, which is the most widely used source for treatment of gynecological cancer. To further enhance harmonization in brachytherapy dosimetry, the IAEA published in 1999 IAEA-TECDOC-1079 entitled 'Calibration of Brachytherapy Sources. Guidelines on Standardized Procedures for the Calibration of Brachytherapy Sources at Secondary Standard Dosimetry Laboratories (SSDLs) and Hospitals'. The report was well received and was distributed in a large number of copies to the members of the IAEA/WHO network of SSDLs and to medical physicists working with brachytherapy. The present report is an update of the aforementioned TECDOC. Whereas TECDOC-1079 described methods for calibrating brachytherapy sources with photon energies at or above those of 192Ir, the current report has a wider scope in that it deals with standardization of calibration of all the most commonly used brachytherapy sources, including both photon and beta emitting sources. The latter sources have been in use for a few decades already, but their calibration methods have been unclear. Methods are also described for calibrating sources used in the rapidly growing field of cardiovascular angioplasty. In this application, irradiation of the vessel wall is done in an attempt to prevent restenosis after

  3. A brachytherapy procedure for carcinoma of the mobile tongue with small source high dose rate remote afterloading method

    International Nuclear Information System (INIS)

    Interstitial brachytherapy was conducted for mobile tongue carcinoma using a new high dose rate remote afterloading machine (microSelectron-HDR) with small 192Ir source. A detailed method was described, approaching from submandibular skin by open-ended stainless steel needles to the tongue lesion, and replacing each needle into flexible nylon tube from the oral cavity. We deal with a new Linked Double-Button technique and treatment policy in this paper. Complete local control was obtained in all 7 patients applied as of February 1992, up to 9-months follow-up, and quality of life of patients after this method was proved as good as that in low dose rate procedure. (author)

  4. Dosimetry of iridium-192 sources used in brachytherapy; Dosimetria de fontes de iridio-192 utilizadas em braquiterapia

    Energy Technology Data Exchange (ETDEWEB)

    Henn, Keli Cristina

    1999-09-01

    The use of high dose rate brachytherapy (HDR) has been increasing in recent years, due to several advantages relative to conventional low dose rate brachytherapy, such as: shorter treatment times, the ability to fractionate treatment (and thus perform many treatments on an outpatient basis) and reduced worker exposures. Most HDR equipment uses small, high activity {sup 192} Ir sources, which are introduced into the patient using a remote system. The dose distribution around these sources is strongly dependent on the size and shape of the active volume and on the encapsulation of the source. The objective of this work is to compare two methods of calibrating sources of {sup 192} Ir, mamely, measurements in air with an ionization thimble chamber or with a well-type ionization chamber. In addition, we measured the anisotropy of the sources and made comparisons with values supplied by the manufacturer, since this factor is taken into account in the planning system algorithm when dose distributions are calculated. The dose was also evaluated at points of clinical interest (i.e. in the rectum and bladder) and compared to values obtained with the Nucletron PLATO-BPS planning system. The use of lead for rectal protection was evaluated in a cylindrical applicator, aiming the further development of a gynecological applicator. The results of the calibration of seven sources showed that the uncertainty in the calibration in a 'jig' system is smaller than 1%, compared to the value supplied by the source manufacturer. The differences between the results obtained with the well-type ionization camera and the 'jig' system were around 2%. The anisotropy showed good agreement with the values supplied by the manufacturer. The results show that the anisotropy factors, in air and water, are approximately constant and equal to 1.0, for angles between 70 deg and 150 deg. For angles smaller than 70 deg the anisotropy factor in water is larger than in air. Results are

  5. A dosimetric uncertainty analysis for photon-emitting brachytherapy sources: Report of AAPM Task Group No. 138 and GEC-ESTRO

    International Nuclear Information System (INIS)

    This report addresses uncertainties pertaining to brachytherapy single-source dosimetry preceding clinical use. The International Organization for Standardization (ISO) Guide to the Expression of Uncertainty in Measurement (GUM) and the National Institute of Standards and Technology (NIST) Technical Note 1297 are taken as reference standards for uncertainty formalism. Uncertainties in using detectors to measure or utilizing Monte Carlo methods to estimate brachytherapy dose distributions are provided with discussion of the components intrinsic to the overall dosimetric assessment. Uncertainties provided are based on published observations and cited when available. The uncertainty propagation from the primary calibration standard through transfer to the clinic for air-kerma strength is covered first. Uncertainties in each of the brachytherapy dosimetry parameters of the TG-43 formalism are then explored, ending with transfer to the clinic and recommended approaches. Dosimetric uncertainties during treatment delivery are considered briefly but are not included in the detailed analysis. For low- and high-energy brachytherapy sources of low dose rate and high dose rate, a combined dosimetric uncertainty <5% (k=1) is estimated, which is consistent with prior literature estimates. Recommendations are provided for clinical medical physicists, dosimetry investigators, and source and treatment planning system manufacturers. These recommendations include the use of the GUM and NIST reports, a requirement of constancy of manufacturer source design, dosimetry investigator guidelines, provision of the lowest uncertainty for patient treatment dosimetry, and the establishment of an action level based on dosimetric uncertainty. These recommendations reflect the guidance of the American Association of Physicists in Medicine (AAPM) and the Groupe Europeen de Curietherapie-European Society for Therapeutic Radiology and Oncology (GEC-ESTRO) for their members and may also be used as

  6. A dosimetric uncertainty analysis for photon-emitting brachytherapy sources: Report of AAPM Task Group No. 138 and GEC-ESTRO

    Energy Technology Data Exchange (ETDEWEB)

    DeWerd, Larry A.; Ibbott, Geoffrey S.; Meigooni, Ali S.; Mitch, Michael G.; Rivard, Mark J.; Stump, Kurt E.; Thomadsen, Bruce R.; Venselaar, Jack L. M. [Department of Medical Physics and Accredited Dosimetry Calibration Laboratory, University of Wisconsin, Madison, Wisconsin 53706 (United States); Department of Radiation Physics, M. D. Anderson Cancer Center, Houston, Texas 77030 (United States); Department of Radiation Oncology, Comprehensive Cancer Center of Nevada, Las Vegas, Nevada 89169 (United States); Ionizing Radiation Division, National Institute of Standards and Technology, Gaithersburg, Maryland 20899 (United States); Department of Radiation Oncology, Tufts University School of Medicine, Boston, Massachusetts 02111 (United States); Santa Maria Radiation Oncology Center, Santa Maria, California 93454 (United States); Departments of Medical Physics and Human Oncology, University of Wisconsin, Madison, Wisconsin 53706 (United States); Department of Medical Physics and Engineering, Instituut Verbeeten, 5042 SB Tilburg (Netherlands)

    2011-02-15

    This report addresses uncertainties pertaining to brachytherapy single-source dosimetry preceding clinical use. The International Organization for Standardization (ISO) Guide to the Expression of Uncertainty in Measurement (GUM) and the National Institute of Standards and Technology (NIST) Technical Note 1297 are taken as reference standards for uncertainty formalism. Uncertainties in using detectors to measure or utilizing Monte Carlo methods to estimate brachytherapy dose distributions are provided with discussion of the components intrinsic to the overall dosimetric assessment. Uncertainties provided are based on published observations and cited when available. The uncertainty propagation from the primary calibration standard through transfer to the clinic for air-kerma strength is covered first. Uncertainties in each of the brachytherapy dosimetry parameters of the TG-43 formalism are then explored, ending with transfer to the clinic and recommended approaches. Dosimetric uncertainties during treatment delivery are considered briefly but are not included in the detailed analysis. For low- and high-energy brachytherapy sources of low dose rate and high dose rate, a combined dosimetric uncertainty <5% (k=1) is estimated, which is consistent with prior literature estimates. Recommendations are provided for clinical medical physicists, dosimetry investigators, and source and treatment planning system manufacturers. These recommendations include the use of the GUM and NIST reports, a requirement of constancy of manufacturer source design, dosimetry investigator guidelines, provision of the lowest uncertainty for patient treatment dosimetry, and the establishment of an action level based on dosimetric uncertainty. These recommendations reflect the guidance of the American Association of Physicists in Medicine (AAPM) and the Groupe Europeen de Curietherapie-European Society for Therapeutic Radiology and Oncology (GEC-ESTRO) for their members and may also be used as

  7. Absorbed dose simulations in near-surface regions using high dose rate Iridium-192 sources applied for brachytherapy

    International Nuclear Information System (INIS)

    Brachytherapy treatment with Iridium-192 high dose rate (HDR) sources is widely used for various tumours and it could be developed in many anatomic regions. Iridium-192 sources are inserted inside or close to the region that will be treated. Usually, the treatment is performed in prostate, gynaecological, lung, breast and oral cavity regions for a better clinical dose coverage compared with other techniques, such as, high energy photons and Cobalt-60 machines. This work will evaluate absorbed dose distributions in near-surface regions around Ir-192 HDR sources. Near-surface dose measurements are a complex task, due to the contribution of beta particles in the near-surface regions. These dose distributions should be useful for non-tumour treatments, such as keloids, and other non-intracavitary technique. For the absorbed dose distribution simulations the Monte Carlo code PENELOPE with the general code penEasy was used. Ir-192 source geometry and a Polymethylmethacrylate (PMMA) tube, for beta particles shield were modelled to yield the percentage depth dose (PDD) on a cubic water phantom. Absorbed dose simulations were realized at the central axis to yield the Ir-192 dose fall-off along central axis. The results showed that more than 99.2% of the absorbed doses (relative to the surface) are deposited in 5 cm depth but with slower rate at higher distances. Near-surface treatments with Ir-192 HDR sources yields achievable measurements and with proper clinical technique and accessories should apply as an alternative for treatment of lesions where only beta sources were used. - Highlights: ► A PMMA (polymethylmethacrylate) tube was used to surround the HDR Ir-192 to shield the beta particles. ► 99.2% of the absorbed doses (relative to the surface) are deposited in 5 cm depth. ► Near-surface treatments with Ir-192 HDR sources yields achievable measurements

  8. Absorbed dose assessment of cardiac and other tissues around the cardiovascular system in brachytherapy with 90Sr/90Y source by Monte Carlo simulation

    International Nuclear Information System (INIS)

    Cardiac disease is one of the most important causes of death in the world. Coronary artery stenosis is a very common cardiac disease. Intravascular brachytherapy (IVBT) is one of the radiotherapy methods which have been used recently in coronary artery radiation therapy for the treatment of restenosis. 90Sr/90Y, a beta-emitting source, is a proper option for cardiovascular brachytherapy. In this research, a Monte Carlo simulation was done to calculate dosimetry parameters and effective equivalent doses to the heart and its surrounding tissues during IVBT. The results of this study were compared with the published experimental data and other simulations performed by different programs but with the same source of radiation. A very good agreement was found between results of this work and the published data. An assessment of the risk for cardiac and other sensitive soft tissues surrounding the treated vessel during 90Sr/90Y IVBT was also performed in the study. (authors)

  9. A systematic evaluation of the dose-rate constant determined by photon spectrometry for 21 different models of low-energy photon-emitting brachytherapy sources

    International Nuclear Information System (INIS)

    The aim of this study was to perform a systematic comparison of the dose-rate constant (Λ) determined by the photon spectrometry technique (PST) with the consensus value (CONΛ) recommended by the American Association of Physicists in Medicine (AAPM) for 21 low-energy photon-emitting interstitial brachytherapy sources. A total of 63 interstitial brachytherapy sources (21 different models with 3 sources per model) containing either 125I (14 models), 103Pd (6 models) or 131Cs (1 model) were included in this study. A PST described by Chen and Nath (2007 Med. Phys. 34 1412-30) was used to determine the dose-rate constant (PSTΛ) for each source model. Source-dependent variations in PSTΛ were analyzed systematically against the spectral characteristics of the emitted photons and the consensus values recommended by the AAPM brachytherapy subcommittee. The values of PSTΛ for the encapsulated sources of 103Pd, 125I and 131Cs varied from 0.661 to 0.678 cGyh-1 U-1, 0.959 to 1.024 cGyh-1U-1 and 1.066 to 1.073 cGyh-1U-1, respectively. The relative variation in PSTΛ among the six 103Pd source models, caused by variations in photon attenuation and in spatial distributions of radioactivity among the source models, was less than 3%. Greater variations in PSTΛ were observed among the 14 125I source models; the maximum relative difference was over 6%. These variations were caused primarily by the presence of silver in some 125I source models and, to a lesser degree, by the variations in photon attenuation and in spatial distribution of radioactivity among the source models. The presence of silver generates additional fluorescent x-rays with lower photon energies which caused the PSTΛ value to vary from 0.959 to 1.019 cGyh-1U-1 depending on the amount of silver used by a given source model. For those 125I sources that contain no silver, their PSTΛ was less variable and had values within 1% of 1.024 cGyh-1U-1. For the 16 source models that currently have an AAPM recommended

  10. Dosimetric characterization of the GammaClip™169Yb low dose rate permanent implant brachytherapy source for the treatment of nonsmall cell lung cancer postwedge resection

    International Nuclear Information System (INIS)

    Purpose: A novel 169Yb low dose rate permanent implant brachytherapy source, the GammaClip™, was developed by Source Production and Equipment Co. (New Orleans, LA) which is designed similar to a surgical staple while delivering therapeutic radiation. In this report, the brachytherapy source was characterized in terms of “Dose calculation for photon-emitting brachytherapy sources with average energy higher than 50 keV: Report of the AAPM and ESTRO” by Perez-Calatayud et al. [Med. Phys. 39, 2904–2929 (2012)] using the updated AAPM Task Group Report No. 43 formalism.Methods: Monte Carlo calculations were performed using Monte Carlo N-Particle 5, version 1.6 in water and air, the in-air photon spectrum filtered to remove photon energies below 10 keV in accordance with TG-43U1 recommendations and previously reviewed 169Yb energy cutoff levels [D. C. Medich, M. A. Tries, and J. M. Munro, “Monte Carlo characterization of an Ytterbium-169 high dose rate brachytherapy source with analysis of statistical uncertainty,” Med. Phys. 33, 163–172 (2006)]. TG-43U1 dosimetric data, including SK, D-dot (r,θ), Λ, gL(r), F(r, θ), φan(r), and φan were calculated along with their statistical uncertainties. Since the source is not axially symmetric, an additional set of calculations were performed to assess the resulting axial anisotropy.Results: The brachytherapy source's dose rate constant was calculated to be (1.22 ± 0.03) cGy h−1 U−1. The uncertainty in the dose to water calculations, D-dot (r,θ), was determined to be 2.5%, dominated by the uncertainties in the cross sections. The anisotropy constant, φan, was calculated to be 0.960 ± 0.011 and was obtained by integrating the anisotropy factor between 1 and 10 cm using a weighting factor proportional to r−2. The radial dose function was calculated at distances between 0.5 and 12 cm, with a maximum value of 1.20 at 5.15 ± 0.03 cm. Radial dose values were fit to a fifth order polynomial and dual exponential

  11. A simplified analytical approach to estimate the parameters required for strength determination of HDR 192Ir brachytherapy sources using a Farmer-type ionization chamber

    International Nuclear Information System (INIS)

    Measuring the strength of high dose rate (HDR) 192Ir brachytherapy sources on receipt from the vendor is an important component of a quality assurance program. Owing to their ready availability in radiotherapy departments, the Farmer-type ionization chambers are also used to determine the strength of HDR 192Ir brachytherapy sources. The use of a Farmer-type ionization chamber requires the estimation of the scatter correction factor along with positioning error (c) and the constant of proportionality (f) to determine the strength of HDR 192Ir brachytherapy sources. A simplified approach based on a least squares method was developed for estimating the values of f and Ms. The seven distance method was followed to record the ionization chamber readings for parameterization of f and Ms. Analytically calculated values of Ms were used to determine the room scatter correction factor (Ksc). The Monte Carlo simulations were also carried out to calculate f and Ksc to verify the magnitude of the parameters determined by the proposed analytical approach. The value of f determined using the simplified analytical approach was found to be in excellent agreement with the Monte Carlo simulated value (within 0.7%). Analytically derived values of Ksc were also found to be in good agreement with the Monte Carlo calculated values (within 1.47%). Being far simpler than the presently available methods of evaluating f, the proposed analytical approach can be adopted for routine use by clinical medical physicists to estimate f by hand calculations. - Highlights: ► RAKR measurement of a brachytherapy source by 7 distance method requires the evaluation of ‘f’. ► A simplified analytical approach based on least square method to evaluate ‘f’ and ‘Ms’ was developed. ► Parameter ‘f’ calculated by proposed analytical approach was verified using the Monte Carlo method. ► Proposed analytical approach can be adopted for routine use to estimate ‘f’.

  12. Prostate brachytherapy

    Science.gov (United States)

    Implant therapy - prostate cancer; Radioactive seed placement; Internal radiation therapy - prostate; High dose radiation (HDR) ... Brachytherapy takes 30 minutes or more, depending on the type of therapy you have. Before the procedure, ...

  13. Determination of surface dose rate of indigenous (32)P patch brachytherapy source by experimental and Monte Carlo methods.

    Science.gov (United States)

    Kumar, Sudhir; Srinivasan, P; Sharma, S D; Saxena, Sanjay Kumar; Bakshi, A K; Dash, Ashutosh; Babu, D A R; Sharma, D N

    2015-09-01

    Isotope production and Application Division of Bhabha Atomic Research Center developed (32)P patch sources for treatment of superficial tumors. Surface dose rate of a newly developed (32)P patch source of nominal diameter 25 mm was measured experimentally using standard extrapolation ionization chamber and Gafchromic EBT film. Monte Carlo model of the (32)P patch source along with the extrapolation chamber was also developed to estimate the surface dose rates from these sources. The surface dose rates to tissue (cGy/min) measured using extrapolation chamber and radiochromic films are 82.03±4.18 (k=2) and 79.13±2.53 (k=2) respectively. The two values of the surface dose rates measured using the two independent experimental methods are in good agreement to each other within a variation of 3.5%. The surface dose rate to tissue (cGy/min) estimated using the MCNP Monte Carlo code works out to be 77.78±1.16 (k=2). The maximum deviation between the surface dose rates to tissue obtained by Monte Carlo and the extrapolation chamber method is 5.2% whereas the difference between the surface dose rates obtained by radiochromic film measurement and the Monte Carlo simulation is 1.7%. The three values of the surface dose rates of the (32)P patch source obtained by three independent methods are in good agreement to one another within the uncertainties associated with their measurements and calculation. This work has demonstrated that MCNP based electron transport simulations are accurate enough for determining the dosimetry parameters of the indigenously developed (32)P patch sources for contact brachytherapy applications. PMID:26086681

  14. Absorbed dose simulations in near-surface regions using high dose rate Iridium-192 sources applied for brachytherapy

    Science.gov (United States)

    Moura, E. S.; Zeituni, C. A.; Sakuraba, R. K.; Gonçalves, V. D.; Cruz, J. C.; Júnior, D. K.; Souza, C. D.; Rostelato, M. E. C. M.

    2014-02-01

    Brachytherapy treatment with Iridium-192 high dose rate (HDR) sources is widely used for various tumours and it could be developed in many anatomic regions. Iridium-192 sources are inserted inside or close to the region that will be treated. Usually, the treatment is performed in prostate, gynaecological, lung, breast and oral cavity regions for a better clinical dose coverage compared with other techniques, such as, high energy photons and Cobalt-60 machines. This work will evaluate absorbed dose distributions in near-surface regions around Ir-192 HDR sources. Near-surface dose measurements are a complex task, due to the contribution of beta particles in the near-surface regions. These dose distributions should be useful for non-tumour treatments, such as keloids, and other non-intracavitary technique. For the absorbed dose distribution simulations the Monte Carlo code PENELOPE with the general code penEasy was used. Ir-192 source geometry and a Polymethylmethacrylate (PMMA) tube, for beta particles shield were modelled to yield the percentage depth dose (PDD) on a cubic water phantom. Absorbed dose simulations were realized at the central axis to yield the Ir-192 dose fall-off along central axis. The results showed that more than 99.2% of the absorbed doses (relative to the surface) are deposited in 5 cm depth but with slower rate at higher distances. Near-surface treatments with Ir-192 HDR sources yields achievable measurements and with proper clinical technique and accessories should apply as an alternative for treatment of lesions where only beta sources were used.

  15. New Brachytherapy Standards Paradigm Shift

    International Nuclear Information System (INIS)

    The absorbed dose to water rate at short distances in water is the quantity of interest for dosimetry in radiotherapy, but no absorbed dose to water primary standards have been available to date for dosimetry of brachytherapy sources. Currently, the procedures to determine the absorbed dose imparted to the patient in brachytherapy treatments are based on measurements traceable to air kerma standards. These procedures are affected by an uncertainty that is larger than the limit recommended by the IAEA dosimetry protocol (IAEA TRS 398 (2000)). Based on this protocol, the goal for the uncertainty of the dose delivered to the target volume should be within 5% (at the level of one standard deviation) to assure the effectiveness of a radiotherapy treatment. The international protocols for the calibration of brachytherapy gamma ray sources are based on the reference air kerma rate or the air kerma strength. The absorbed dose to water, in water at the reference position around a brachytherapy source is then calculated by applying the formalism of the protocols based on a conversion constant, the dose rate constant Λ, specific for the characteristics and geometry of the brachytherapy source. The determination of this constant relies on Monte Carlo simulations and relative measurements performed with passive dosimeters, and therefore it is typically affected by large uncertainties, larger than 5% (at the level of one standard deviation). The conversion procedure needed for brachytherapy dosimetry is a source of additional uncertainty on the final value of the absorbed dose imparted to the patient. It is due to a lack of metrology standards that makes dosimetry of brachytherapy sources less accurate than dosimetry of external radiation beams produced by 60Co sources and accelerators currently used in external beam radiotherapy. This paper reviews the current developments of absorbed dose to water primary standards for brachytherapy and the rationale for the choice of the

  16. Radiological Characterization Technical Report on Californium-252 Sealed Source Transuranic Debris Waste for the Off-Site Source Recovery Project at Los Alamos National Laboratory

    Energy Technology Data Exchange (ETDEWEB)

    Feldman, Alexander [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2014-04-24

    This document describes the development and approach for the radiological characterization of Cf-252 sealed sources for shipment to the Waste Isolation Pilot Plant. The report combines information on the nuclear material content of each individual source (mass or activity and date of manufacture) with information and data on the radionuclide distributions within the originating nuclear material. This approach allows for complete and accurate characterization of the waste container without the need to take additional measurements. The radionuclide uncertainties, developed from acceptable knowledge (AK) information regarding the source material, are applied to the summed activities in the drum. The AK information used in the characterization of Cf-252 sealed sources has been qualified by the peer review process, which has been reviewed and accepted by the Environmental Protection Agency.

  17. Stem effect of a Ce3+ doped SiO2 optical dosimeter irradiated with a 192Ir HDR brachytherapy source

    International Nuclear Information System (INIS)

    Fiber-optic-coupled scintillation dosimeters are characterized by their small active volume if compared to other existing systems. However, they potentially show a greater stem effect, especially in external beam radiotherapy where the Cerenkov effect is not negligible. In brachytherapy, due to the lower energies and the shorter high dose range of the employed sources, the impact of the stem effect to the detector accuracy might be low. In this work, the stem effect of a Ce3+ doped SiO2 scintillation detector coupled to a SiO2 optical fiber was studied for high dose rate brachytherapy applications. Measurements were performed in a water phantom at changing source-detector mutual positions. The same irradiations were performed with a passive optical fiber, which doesn't have the dosimeter at its end. The relative contribution of the passive fiber with respect to the uncorrected readings of the detector in each one of the investigated source dwell positions was evaluated. Furthermore, the dosimeter was calibrated both neglecting and correcting its response for the passive fiber readings. The obtained absolute dose measurements were then compared to the dose calculations resulting from the treatment planning system. Dosimeter uncertainties with and without taking into account the passive fiber readings were generally below 2.8% and 4.3%, respectively. However, a particular exception results when the source is positioned near to the optical fiber, where the detector underestimates the dose (−8%) or at source-detector longitudinal distances higher than 3 cm. The obtained results show that the proposed dosimeter might be adopted in high dose rate prostate brachytherapy with satisfactory accuracy, without the need for any stem effect correction. However, accuracy further improves by subtraction of the noise signal produced by the passive optical fiber. - Highlights: • A scintillation detector with 0.9 mm diameter was developed for in vivo dosimetry in

  18. WE-A-17A-02: BEST IN PHYSICS (THERAPY) - Development of a Calorimeter for the Measurement of the Power Emitted From LDR Brachytherapy Sources

    International Nuclear Information System (INIS)

    Purpose: Model-based dose calculation algorithms for brachytherapy sources are designed to compute dose per particle or dose per unit energy leaving the encapsulation of a brachytherapy source. As such, the power leaving the encapsulation of a source, called emitted power (EP), would be a natural source strength metric for these new algorithms. However, no instrument is currently capable of an absolute measurement of EP. A calorimeter operating with a liquid helium thermal sink was designed and constructed to measure the EP of low-dose rate (LDR) I-125 and Pd-103 brachytherapy sources. Methods: Calorimeter design was optimized through thermal and Monte Carlo (MC) modeling. Thermal modeling showed that specific thermal conditions would be necessary for accurate calorimeter measurements. These conditions were experimentally verified. The EP of two LDR I-125 source models was measured. An air-kermastrength (AKS)-to-EP conversion coefficient was determined through MC simulations and applied to well-type ionization chamber measurements of AKS to enable comparison with EP measurements. Results: MCdetermined EP per unit AKS conversion coefficients were source model dependent and are on the order of 0.1 μW/U. The signal-to-noise ratio was a function of source strength, and was 294 for a 0.5 μW source. Measurements were repeatable to within 3.6% for a 0.5 μW source. Initial EP measurements were made with two I-125 source models, a 5.7 U Oncura 6711 and a 2.9 U Best Medical 2301. Model 2301 results agreed with the MC-converted AKS value to within the measurement uncertainty of 4.3% at k=1. The Model 6711 results were systematically high and are under investigation. Conclusion: A calorimeter was designed to provide an absolute measurement of the EP for LDR brachytherapy sources and preliminary EP measurements have been made. This new calorimeter design shows promise of providing a more fundamentally useful source strength standard

  19. Study and parameters survey for iodine-125 source dosimetry to be applied in brachytherapy

    International Nuclear Information System (INIS)

    The use of brachytherapy technique with iodine-125 seeds to prostate cancer treatment has been used for decades with good clinical outcomes. To aim the Brazilian population necessities, IPEN-CNEN/SP developed the iodine-125 seed prototype with national technology. The objectives of this work are the development and the study of dosimetric procedures associates with the experimental acquisition of the useful parameters for the iodine-125 dosimetric characterization and to evaluate if the developed procedures, in this work, have the basic conditions to determinate the dosimetric analysis, that are fundamental for clinical procedures. The dosimeters selected for the analysis are the TLD-100 (LiF:Mg,Ti), initially these dosimeters were submitted for two selection steps to choose the dosimeters more reproducible for the dosimetric analysis. The two steps were the selection by the mass of the dosimeters and the reproducibility after four irradiation series in a Cobalt-60 irradiator (CTR-IPEN). Afterwards these steps, the dosimeters were irradiated in linear accelerator with 6 MV energy (Service of Radiotherapy - Hospital Israelita Albert Einstein) to yield the individual calibration factors to each dosimeter. After, the dosimeters were used to the irradiations with iodine-125 seed, 6711 model, (GE-Healthcare). The irradiations and others analysis with iodine-125 seeds yield the useful values for the determination of the parameters suggested by the AAPM (American Association of Physicists in Medicine): constant of dose rate, geometry function, dose radial function and anisotropy function. The results showed good agreement with the values published by the literature, for the same iodine- 125 model, this fact confirms that the realized parameters will be able to be used for the IPEN-CNEN iodine-125 seeds dosimetry and quality control. (author)

  20. Quantification of iodine in porous hydroxyapatite matrices for application as radioactive sources in brachytherapy

    Directory of Open Access Journals (Sweden)

    Kássio André Lacerda

    2007-07-01

    Full Text Available In this study, non-radioactive iodine was incorporated in two types of biodegradable hydroxyapatite-based porous matrices (HA and HACL through impregnation process from sodium iodine aqueous solutions with varying concentrations (0.5 and 1.0 mol/L . The results revealed that both systems presented a high capacity of incorporating iodine into their matrices. The quantity of incorporated iodine was measured through Neutron Activation Analysis (NAA. The porous ceramic matrices based on hydroxyapatite demonstrated a great potential for uses in low dose rate (LDR brachytherapy.Materiais cerâmicos porosos à base de compostos de fosfatos de cálcio (CFC vêm sendo estudados e desenvolvidos para várias aplicações biomédicas tais como implantes, sistemas para liberação de drogas e fontes radioativas para braquiterapia. Dois tipos de matrizes porosas biodegradáveis de hidroxiapatita (HA e HACL foram avaliadas em termos da capacidade de incorporação de iodo em suas estruturas. Resultados revelaram que as matrizes porosas a base de hidroxiapatita apresentaram alta capacidade de incorporar iodo em sua estrutura. A quantidade de iodo foi mensurada através da técnica de Análise por Ativação Nêutronica (AAN. As matrizes cerâmicas porosas à base de hidroxiapatita demostraram ter grande potencial para aplicação em braquiterapia de baixa taxa de dose (LDR - Low Dose Rate.

  1. Cluster pattern analysis of energy deposition sites for the brachytherapy sources 103Pd, 125I, 192Ir, 137Cs, and 60Co

    International Nuclear Information System (INIS)

    Analysing the pattern of energy depositions may help elucidate differences in the severity of radiation-induced DNA strand breakage for different radiation qualities. It is often claimed that energy deposition (ED) sites from photon radiation form a uniform random pattern, but there is indication of differences in RBE values among different photon sources used in brachytherapy. The aim of this work is to analyse the spatial patterns of EDs from 103Pd, 125I, 192Ir, 137Cs sources commonly used in brachytherapy and a 60Co source as a reference radiation. The results suggest that there is both a non-uniform and a uniform random component to the frequency distribution of distances to the nearest neighbour ED. The closest neighbouring EDs show high spatial correlation for all investigated radiation qualities, whilst the uniform random component dominates for neighbours with longer distances for the three higher mean photon energy sources (192Ir, 137Cs, and 60Co). The two lower energy photon emitters (103Pd and 125I) present a very small uniform random component. The ratio of frequencies of clusters with respect to 60Co differs up to 15% for the lower energy sources and less than 2% for the higher energy sources when the maximum distance between each pair of EDs is 2 nm. At distances relevant to DNA damage, cluster patterns can be differentiated between the lower and higher energy sources. This may be part of the explanation to the reported difference in RBE values with initial DSB yields as an endpoint for these brachytherapy sources. (paper)

  2. Comparison of organ doses for patients undergoing balloon brachytherapy of the breast with HDR 192Ir or electronic sources using Monte Carlo simulations in a heterogeneous human phantom

    International Nuclear Information System (INIS)

    Purpose: Accelerated partial breast irradiation via interstitial balloon brachytherapy is a fast and effective treatment method for certain early stage breast cancers. The radiation can be delivered using a conventional high-dose rate (HDR) 192Ir gamma-emitting source or a novel electronic brachytherapy (eBx) source which uses lower energy x rays that do not penetrate as far within the patient. A previous study [A. Dickler, M. C. Kirk, N. Seif, K. Griem, K. Dowlatshahi, D. Francescatti, and R. A. Abrams, ''A dosimetric comparison of MammoSite high-dose-rate brachytherapy and Xoft Axxent electronic brachytherapy,'' Brachytherapy 6, 164-168 (2007)] showed that the target dose is similar for HDR 192Ir and eBx. This study compares these sources based on the dose received by healthy organs and tissues away from the treatment site. Methods: A virtual patient with left breast cancer was represented by a whole-body, tissue-heterogeneous female voxel phantom. Monte Carlo methods were used to calculate the dose to healthy organs in a virtual patient undergoing balloon brachytherapy of the left breast with HDR 192Ir or eBx sources. The dose-volume histograms for a few organs which received large doses were also calculated. Additional simulations were performed with all tissues in the phantom defined as water to study the effect of tissue inhomogeneities. Results: For both HDR 192Ir and eBx, the largest mean organ doses were received by the ribs, thymus gland, left lung, heart, and sternum which were close to the brachytherapy source in the left breast. eBx yielded mean healthy organ doses that were more than a factor of ∼1.4 smaller than for HDR 192Ir for all organs considered, except for the three closest ribs. Excluding these ribs, the average and median dose-reduction factors were ∼28 and ∼11, respectively. The volume distribution of doses in nearby soft tissue organs that were outside the PTV were also improved with eBx. However, the maximum dose to the closest rib

  3. Study and methodology development for quality control in the production process of iodine-125 radioactive sealed sources applied to brachytherapy

    International Nuclear Information System (INIS)

    Today cancer is the second cause of death by disease in several countries, including Brazil. Excluding skin cancer, prostate cancer is the most incident in the population. Prostate tumor can be treated by several ways, including brachytherapy, which consists in introducing sealed radioactive sources (Iodine - 125 seeds) inside the tumor. The target region of treatment receives a high radiation dose, but healthy neighbor tissues receive a significantly reduced radiation dose. The seed is made of a welding sealed titanium capsule, 0.8 mm external diameter and 4.5 mm length, enclosing a 0.5 mm diameter silver wire with Iodine-125 adsorbed. After welded, the seeds have to be submitted to a leak test to prevent any radioactive material release. The aims of this work were: (a) the study of the different leakage test methods applied to radioactive seeds and recommended by the ISO 997820, (b) the choice of the appropriate method and (c) the flowchart determination of the process to be used during the seeds production. The essays exceeded the standards with the use of ultra-sound during immersion and the corresponding benefits to leakage detection. Best results were obtained with the immersion in distilled water at 20 degree C for 24 hours and distilled water at 70 degree C for 30 minutes. These methods will be used during seed production. The process flowchart has all the phases of the leakage tests according to the sequence determined in the experiments. (author)

  4. On source models for (192)Ir HDR brachytherapy dosimetry using model based algorithms.

    Science.gov (United States)

    Pantelis, Evaggelos; Zourari, Kyveli; Zoros, Emmanouil; Lahanas, Vasileios; Karaiskos, Pantelis; Papagiannis, Panagiotis

    2016-06-01

    A source model is a prerequisite of all model based dose calculation algorithms. Besides direct simulation, the use of pre-calculated phase space files (phsp source models) and parameterized phsp source models has been proposed for Monte Carlo (MC) to promote efficiency and ease of implementation in obtaining photon energy, position and direction. In this work, a phsp file for a generic (192)Ir source design (Ballester et al 2015) is obtained from MC simulation. This is used to configure a parameterized phsp source model comprising appropriate probability density functions (PDFs) and a sampling procedure. According to phsp data analysis 15.6% of the generated photons are absorbed within the source, and 90.4% of the emergent photons are primary. The PDFs for sampling photon energy and direction relative to the source long axis, depend on the position of photon emergence. Photons emerge mainly from the cylindrical source surface with a constant probability over  ±0.1 cm from the center of the 0.35 cm long source core, and only 1.7% and 0.2% emerge from the source tip and drive wire, respectively. Based on these findings, an analytical parameterized source model is prepared for the calculation of the PDFs from data of source geometry and materials, without the need for a phsp file. The PDFs from the analytical parameterized source model are in close agreement with those employed in the parameterized phsp source model. This agreement prompted the proposal of a purely analytical source model based on isotropic emission of photons generated homogeneously within the source core with energy sampled from the (192)Ir spectrum, and the assignment of a weight according to attenuation within the source. Comparison of single source dosimetry data obtained from detailed MC simulation and the proposed analytical source model show agreement better than 2% except for points lying close to the source longitudinal axis. PMID:27191179

  5. On source models for 192Ir HDR brachytherapy dosimetry using model based algorithms

    Science.gov (United States)

    Pantelis, Evaggelos; Zourari, Kyveli; Zoros, Emmanouil; Lahanas, Vasileios; Karaiskos, Pantelis; Papagiannis, Panagiotis

    2016-06-01

    A source model is a prerequisite of all model based dose calculation algorithms. Besides direct simulation, the use of pre-calculated phase space files (phsp source models) and parameterized phsp source models has been proposed for Monte Carlo (MC) to promote efficiency and ease of implementation in obtaining photon energy, position and direction. In this work, a phsp file for a generic 192Ir source design (Ballester et al 2015) is obtained from MC simulation. This is used to configure a parameterized phsp source model comprising appropriate probability density functions (PDFs) and a sampling procedure. According to phsp data analysis 15.6% of the generated photons are absorbed within the source, and 90.4% of the emergent photons are primary. The PDFs for sampling photon energy and direction relative to the source long axis, depend on the position of photon emergence. Photons emerge mainly from the cylindrical source surface with a constant probability over  ±0.1 cm from the center of the 0.35 cm long source core, and only 1.7% and 0.2% emerge from the source tip and drive wire, respectively. Based on these findings, an analytical parameterized source model is prepared for the calculation of the PDFs from data of source geometry and materials, without the need for a phsp file. The PDFs from the analytical parameterized source model are in close agreement with those employed in the parameterized phsp source model. This agreement prompted the proposal of a purely analytical source model based on isotropic emission of photons generated homogeneously within the source core with energy sampled from the 192Ir spectrum, and the assignment of a weight according to attenuation within the source. Comparison of single source dosimetry data obtained from detailed MC simulation and the proposed analytical source model show agreement better than 2% except for points lying close to the source longitudinal axis.

  6. A dual-plane co-RASOR technique for accurate and rapid tracking and position verification of an Ir-192 source for single fraction HDR brachytherapy

    Science.gov (United States)

    de Leeuw, Hendrik; Moerland, Marinus A.; van Vulpen, Marco; Seevinck, Peter R.; Bakker, Chris J. G.

    2013-11-01

    Effective high-dose-rate (HDR) treatment requires accurate and independent treatment verification to ensure that the treatment proceeds as prescribed, in particular if a high dose is given, as in single fraction therapy. Contrary to CT imaging and fluoroscopy, MR imaging provides high soft tissue contrast. Conventional MR techniques, however, do not offer the temporal resolution in combination with the 3D spatial resolution required for accurate brachytherapy source localization. We have developed an MR imaging method (center-out RAdial Sampling with Off-Resonance (co-RASOR)) that generates high positive contrast in the geometrical center of field perturbing objects, such as HDR brachytherapy sources. co-RASOR generates high positive contrast in the geometric center of an Ir-192 source by applying a frequency offset to center-out encoded data. To obtain high spatial accuracy in 3D with adequate temporal resolution, two orthogonal center-out encoded 2D images are applied instead of a full 3D acquisition. Its accuracy in 3D is demonstrated by 3D MRI and CT. The 2D images show high positive contrast in the geometric center of non-radioactive Ir-192 sources, with signal intensities up to 160% of the average signal intensity in the surrounding medium. The accuracy with which the center of the Ir-192 source is located by the dual-plane MRI acquisition corresponds closely to the accuracy obtained by 3D MRI and CT imaging. The positive contrast is shown to be obtained in homogeneous and in heterogeneous tissue. The dual-plane MRI technique allows the brachytherapy source to be tracked in 3D with millimeter accuracy with a temporal resolution of approximately 4 s.

  7. Radiological protection on interstitial brachytherapy and dose determination and exposure rate of an Ir-192 source through the MCNP-4B

    International Nuclear Information System (INIS)

    The present work was carried out in the Neurological Sciences Institute having as objective to determine the dose and the rate of exhibition of the sources of Iridium 192, Iodine 125 and Palladium 103; which are used to carry out implant in the Interstitial Brachytherapy according to the TG43. For it we carry out a theoretical calculation, its are defined in the enter file: the geometry, materials of the problem and the radiation source, etc; in the MCNP-4B Monte Carlo code, considering a punctual source and for the dose determination we simulate thermoluminescent dosemeters (TLD): at 5 cm, 50 cm, 100 cm and 200 cm of the source. Our purpose is to analyze the radioprotection measures that should take into account in this Institute in which are carried out brain biopsies using a Micro mar stereotactic mark, and in a near future with the collaboration of a doctor and a cuban physique seeks to be carried out the Interstitial Brachytherapy technique with sources of Ir-192 for patient with tumors like glioblastoma, astrocytoma, etc. (Author)

  8. Determination of dosimetric characteristics of 125I-103Pd brachytherapy source with Monte-Carlo method

    International Nuclear Information System (INIS)

    According to dose parameters calculation formula of seed source recommended by AAPM TG43U1, 125I-103Pd seed source dose parameters calculation formula and a variety of radionuclides composite seed source of dose parameters calculation formula can be obtain. Dose rate constant, radial dose function and anisotropy function of 125I-103Pd composite seed source are calculated by Monte-Carlo method, Empiric equations are obtained for radial dose function and anisotropy function by curve fitting. Comparisons with the relative data recommend by AAPM are performed. For the single source, the deviation of dose rate constant is 0.959 (cGy·h-1·U-1), and with 0.6093% from the AAPM. (authors)

  9. Numerical calculation of relative dose rates from spherical 106Ru beta sources used in ophthalmic brachytherapy

    Directory of Open Access Journals (Sweden)

    Eduardo de Paiva

    2015-01-01

    Full Text Available Concave beta sources of 106Ru/106Rh are used in radiotherapy to treat ophthalmic tumors. However, a problem that arises is the difficult determination of absorbed dose distributions around such sources mainly because of the small range of the electrons and the steep dose gradients. In this sense, numerical methods have been developed to calculate the dose distributions around the beta applicators. In this work a simple code in Fortran language is developed to estimate the dose rates along the central axis of 106Ru/106Rh curved plaques by numerical integration of the beta point source function and results are compared with other calculated data.

  10. Numerical calculation of relative dose rates from spherical 106Ru beta sources used in ophthalmic brachytherapy

    Science.gov (United States)

    de Paiva, Eduardo

    Concave beta sources of 106Ru/106Rh are used in radiotherapy to treat ophthalmic tumors. However, a problem that arises is the difficult determination of absorbed dose distributions around such sources mainly because of the small range of the electrons and the steep dose gradients. In this sense, numerical methods have been developed to calculate the dose distributions around the beta applicators. In this work a simple code in Fortran language is developed to estimate the dose rates along the central axis of 106Ru/106Rh curved plaques by numerical integration of the beta point source function and results are compared with other calculated data.

  11. Preparation and evaluation of various 32P sources for intravascular brachytherapy

    International Nuclear Information System (INIS)

    A relatively high per cent of restenoses, being a long-term complication of percutaneous transluminal coronary angioplasty (PTCA), can be significantly reduced by short-range ionizing radiation applied locally, immediately after PTCA. In search for dosimetrically favourable and easy to handle radiation sources for this purpose, we tried a pure β- emitter 32P (t1/2=14.3 days). Ways of preparation of 32 P sources were the following: (1) Neutron activation of 31P layers implanted into metallic surfaces by ionic methods; (2) Conversion coating of metallic surfaces in aqueous solutions containing 32PO43- ions; (3) Direct application of Na2H32 PO4 solutions in the angioplasty balloon. It was shown that: (1) 32 P sources obtained by 31 P ion implantation followed by neutron activation can be useful, but only if activation of the support material by thermal neutrons is negligible; (2) Phosphate layers on stainless steel surface exhibit rather poor adhesion. Similar layers on titanium require further studies; (3) Liquid 32 P sources ensure very good radial dose distribution but only utmost care in filling the balloon can give a reliable activity-dose dependence. Dosimetry of liquid sources, performed in a PMMA phantom by thermoluminescence method showed that 32 P sources of radioactive concentration of 200 MBq/cm3 can deposit therapeutic dose during about 12 min of exposition. TL detectors manufactured for this purpose in our laboratory show very good spatial resolution and can be recommended for similar studies. (author)

  12. Development of an asymmetric multiple-position neutron source (AMPNS) method to monitor the criticality of a degraded reactor core

    International Nuclear Information System (INIS)

    An analytical/experimental method has been developed to monitor the subcritical reactivity and unfold the k/sub infinity/ distribution of a degraded reactor core. The method uses several fixed neutron detectors and a Cf-252 neutron source placed sequentially in multiple positions in the core. Therefore, it is called the Asymmetric Multiple Position Neutron Source (AMPNS) method. The AMPNS method employs nucleonic codes to analyze the neutron multiplication of a Cf-252 neutron source. An optimization program, GPM, is utilized to unfold the k/sub infinity/ distribution of the degraded core, in which the desired performance measure minimizes the error between the calculated and the measured count rates of the degraded reactor core. The analytical/experimental approach is validated by performing experiments using the Penn State Breazeale TRIGA Reactor (PSBR). A significant result of this study is that it provides a method to monitor the criticality of a damaged core during the recovery period

  13. The theoretical basis and clinical methodology for stereotactic interstitial brain tumor irradiation using iododeoxyuridine as a radiation sensitizer and samarium-145 as a brachytherapy source

    International Nuclear Information System (INIS)

    High grade astrocytomas have proven resistant to all conventional therapy. A technique to produce radiation enhancement during interstitial brain tumor irradiation by using a radiation sensitizer (IdUrd) and by stimulation of Auger electron cascades through absorption of low energy photons in iodine (Photon activation) is described. Clinical studies using IdUrd, 192Ir as a brachytherapy source, and external radiation have produced promising results. Substituting samarium-145 for 192Ir in this protocol is expected to produce enhanced results. 15 refs

  14. A photon spectrometric dose-rate constant determination for the Advantage Pd-103 brachytherapy source

    International Nuclear Information System (INIS)

    Purpose: Although several dosimetric characterizations using Monte Carlo simulation and thermoluminescent dosimetry (TLD) have been reported for the new Advantage Pd-103 source (IsoAid, LLC, Port Richey, FL), no AAPM consensus value has been established for the dosimetric parameters of the source. The aim of this work was to perform an additional dose-rate constant (Λ) determination using a recently established photon spectrometry technique (PST) that is independent of the published TLD and Monte Carlo techniques. Methods: Three Model IAPD-103A Advantage Pd-103 sources were used in this study. The relative photon energy spectrum emitted by each source along the transverse axis was measured using a high-resolution germanium spectrometer designed for low-energy photons. For each source, the dose-rate constant was determined from its emitted energy spectrum. The PST-determined dose-rate constant (PSTΛ) was then compared to those determined by TLD (TLDΛ) and Monte Carlo (MCΛ) techniques. A likely consensus Λ value was estimated as the arithmetic mean of the average Λ values determined by each of three different techniques. Results: The average PSTΛ value for the three Advantage sources was found to be (0.676±0.026) cGyh-1 U-1. Intersource variation in PSTΛ was less than 0.01%. The PSTΛ was within 2% of the reported MCΛ values determined by PTRAN, EGSnrc, and MCNP5 codes. It was 3.4% lower than the reported TLDΛ. A likely consensus Λ value was estimated to be (0.688±0.026) cGyh-1 U-1, similar to the AAPM consensus values recommended currently for the Theragenics (Buford, GA) Model 200 (0.686±0.033) cGyh-1 U-1, the NASI (Chatsworth, CA) Model MED3633 (0.688±0.033) cGyh-1 U-1, and the Best Medical (Springfield, VA) Model 2335 (0.685±0.033) cGyh-1 U-1103Pd sources. Conclusions: An independent Λ determination has been performed for the Advantage Pd-103 source. The PSTΛ obtained in this work provides additional information needed for establishing a more

  15. Impact of the differential fluence distribution of brachytherapy sources on the spectroscopic dose-rate constant

    Energy Technology Data Exchange (ETDEWEB)

    Malin, Martha J.; Bartol, Laura J.; DeWerd, Larry A., E-mail: mmalin@wisc.edu, E-mail: ladewerd@wisc.edu [Department of Medical Physics, University of Wisconsin - Madison, Madison, Wisconsin 53705 (United States)

    2015-05-15

    Purpose: To investigate why dose-rate constants for {sup 125}I and {sup 103}Pd seeds computed using the spectroscopic technique, Λ{sub spec}, differ from those computed with standard Monte Carlo (MC) techniques. A potential cause of these discrepancies is the spectroscopic technique’s use of approximations of the true fluence distribution leaving the source, φ{sub full}. In particular, the fluence distribution used in the spectroscopic technique, φ{sub spec}, approximates the spatial, angular, and energy distributions of φ{sub full}. This work quantified the extent to which each of these approximations affects the accuracy of Λ{sub spec}. Additionally, this study investigated how the simplified water-only model used in the spectroscopic technique impacts the accuracy of Λ{sub spec}. Methods: Dose-rate constants as described in the AAPM TG-43U1 report, Λ{sub full}, were computed with MC simulations using the full source geometry for each of 14 different {sup 125}I and 6 different {sup 103}Pd source models. In addition, the spectrum emitted along the perpendicular bisector of each source was simulated in vacuum using the full source model and used to compute Λ{sub spec}. Λ{sub spec} was compared to Λ{sub full} to verify the discrepancy reported by Rodriguez and Rogers. Using MC simulations, a phase space of the fluence leaving the encapsulation of each full source model was created. The spatial and angular distributions of φ{sub full} were extracted from the phase spaces and were qualitatively compared to those used by φ{sub spec}. Additionally, each phase space was modified to reflect one of the approximated distributions (spatial, angular, or energy) used by φ{sub spec}. The dose-rate constant resulting from using approximated distribution i, Λ{sub approx,i}, was computed using the modified phase space and compared to Λ{sub full}. For each source, this process was repeated for each approximation in order to determine which approximations used in

  16. Low dose rate 137Cs Brachytherapy source calibration with farmer type ionisation chamber and specialised fabricated jig in Korle-Bu Teaching Hospital

    International Nuclear Information System (INIS)

    An important part of a general quality assurance (QA) program for brachytherapy dosimetry is the source calibration because wide ranges of uncertainties are quoted by manufactures. This research is aimed at calibrating LDR 137Cs brachytherapy source in the Korle-Bu Teaching Hospital by multiple-distance air kerma measurement technique using a specialized designed jig and a calibrated therapy ionization chamber. Specialized jig was fabricated with source holder positions and ionization chamber positions on the jig. Farmer type ionization chamber of volume 0.6cm3 was used with and without build up cap. The results were validated using well type ionization chamber on channels on 1 and 5 taking into account decay correction. Air Kerma rates were determined at multiple distances between 8cm to 12cm from measured charges recorded by Max 4000 electrometer. The scatter dose relationship described by Ezzell [1992] was used to determine scattered radiation. The analytical method of determining air kerma calibration factor of 137Cs described by Sharma et.al [2011] was used to determine beam quality correction factor for the 137Cs. Beam attenuation was determined. Experimental data were compared with manufacturer's quoted source strength for verification. Well type ionization chamber results and experimental results on channel V1 and V5 deviated by 2.39% and 1.58% respectively. Experimental data deviated by 4.73% and 1.24% from theoretical data on channels V1 and V5 respectively. The mean of the experimental data deviated from the theoretical data by ±3.1% and from the well type measurements data by ±1.98%. The well type chamber results compared well with the experimental data. This is an indication that the method used for source calibration is a reliable alternative method of source calibration. The method used in this work has proven to be an efficient way of determining the actual source strength of the LDR brachytherapy 137Cs source in Korle-Bu Radiotherapy Centre

  17. Development of a well- type chamber for measurement of source activation in brachytherapy

    International Nuclear Information System (INIS)

    Objective: To develop a well-type chamber for measuring air kerma strength of source and improve accuracy for source activity. Methods: By drawing advanced experience from abroad and combining the condition of our country, the authors designed a plan, drew the blueprint, selected the material, processed and assembled the well- type chamber, and carried out a performance test. Result: The imported and self-made well- type chambers were measured in the same condition for comparison. The results should be that the long- term stability of the self-made well- type chamber is 0.4 %, and the technique index is 2%; the recombination rate of ionized charges is 0.9995% and the technique index is 1.000; the measurement accuracy of the well-type chamber is 0.02%, and the technique index is 0.5%. For the self-made well-type chamber, the flat response of peak sensitivity is fixed while for imported one the flat response changes around 0.1% within 5 mm of peak sensitivity. Conclusions: The strong points of the self-made well-type chamber are quick speed and accuracy in measurement and can measure for 192Ir, 125I and 103 Pd sources. Its measurement range is from 3. 7 MBq to 7. 4 x 105 MBq. The development of the well-type chamber fills the gaps of on -site measurement instruments and becomes a product with independent intellectual property right in our country. (authors)

  18. Definition study of the project Dosimetry Brachytherapy

    International Nuclear Information System (INIS)

    The purpose of the research project Dosimetry Brachytherapy is the standardization of calibration methods and quality control procedures used for Brachytherapy sources. Proposals to develop measurement standards and methods for calibrating these sources are presented. Brachytherapy sources will be calibrated in terms of reference airkerma rate or in terms of absorbed dose in water. Therefore, in this project, special attention will be given to the in-phantom measurement method described by Meertens and the use of re-entrant ionisation chambers as transfer standards. In this report, a workplan and time schedule is included. (author). 19 refs.; 1 fig

  19. Evaluation of Gafchromic EBT2 film for the measurement of anisotropy function for high-dose-rate 192Ir brachytherapy source with respect to thermoluminescent dosimetry

    International Nuclear Information System (INIS)

    Aim: The aim of this work was to assess the suitability of the use of a Gafchromic EBT2 film for the measurement of anisotropy function for micro Selectron HDR 192Ir (classic) source with a comparative dosimetry method using a Gafchromic EBT2 film and thermoluminescence dosimeters (TLDs). Background: Sealed linear radiation sources are commonly used for high dose rate (HDR) brachytherapy treatments. Due to self-absorption and oblique filtration of radiation in the source capsule material, an inherent anisotropy is present in the dose distribution around the source which can be described by a measurable two-dimensional anisotropy function, F(γ, Θ ). Materials and methods: Measurements were carried out in a specially designed and locally fabricated PMMA phantom with provisions to accommodate miniature LiF TLD rods and EBT2 film dosimeters at identical radial distances with respect to the 192Ir source. Results: The data of anisotropy function generated by the use of the Gafchromic EBT2 film method are in agreement with their TLD measured values within 4%. The produced data are also consistent with their experimental and Monte Carlo calculated results for this source available in the literature. Conclusion: Gafchromic EBT2 film was found to be a feasible dosimeter in determining anisotropy in the dose distribution of 192Ir source. It offers high resolution and is a viable alternative to TLD dosimetry at discrete points. The method described in this paper is useful for comparing the performances of detectors and can be applied for other brachytherapy sources as well. (authors)

  20. Evaluation of a lithium formate EPR dosimetry system for dose measurements around Ir-192 brachytherapy sources

    OpenAIRE

    Antonovic, Laura; Gustafsson, Håkan; Alm Carlsson, Gudrun; Carlsson Tedgren, Åsa

    2009-01-01

    A dosimetry system using lithium formate monohydrate (HCO2Li center dot H2O) as detector material and electron paramagnetic resonance (EPR) spectroscopy for readout has been used to measure absorbed dose distributions around clinical Ir-192 sources. Cylindrical tablets with diameter of 4.5 mm, height of 4.8 mm, and density of 1.26 g/cm(3) were manufactured. Homogeneity test and calibration of the dosimeters were performed in a 6 MV photon beam. Ir-192 irradiations were performed in a PMMA pha...

  1. Dose distribution in water for monoenergetic photon point sources in the energy range of interest in brachytherapy: Monte Carlo simulations with PENELOPE and GEANT4

    CERN Document Server

    Almansa, J F; Anguiano, M; Guerrero, R; Lallena, A M; Al-Dweri, Feras M.O.; Almansa, Julio F.; Guerrero, Rafael

    2006-01-01

    Monte Carlo calculations using the codes PENELOPE and GEANT4 have been performed to characterize the dosimetric properties of monoenergetic photon point sources in water. The dose rate in water has been calculated for energies of interest in brachytherapy, ranging between 10 keV and 2 MeV. A comparison of the results obtained using the two codes with the available data calculated with other Monte Carlo codes is carried out. A chi2-like statistical test is proposed for these comparisons. PENELOPE and GEANT4 show a reasonable agreement for all energies analyzed and distances to the source larger than 1 cm. Significant differences are found at distances from the source up to 1 cm. A similar situation occurs between PENELOPE and EGS4.

  2. An absorbed dose to water standard for HDR 192Ir brachytherapy sources based on water calorimetry: Numerical and experimental proof-of-principle

    International Nuclear Information System (INIS)

    Water calorimetry is an established technique for absorbed dose to water measurements in external beams. In this paper, the feasibility of direct absorbed dose measurements for high dose rate (HDR) iridium-192 (192Ir) sources using water calorimetry is established. Feasibility is determined primarily by a balance between the need to obtain sufficient signal to perform a reproducible measurement, the effect of heat loss on the measured signal, and the positioning uncertainty affecting the source-detector distance. The heat conduction pattern generated in water by the Nucletron microSelectron-HDR 192Ir brachytherapy source was simulated using COMSOL MULTIPHYSICSTM software. Source heating due to radiation self-absorption was calculated using EGSnrcMP. A heat-loss correction kc was calculated as the ratio of the temperature rise under ideal conditions to temperature rise under realistic conditions. The calorimeter setup used a parallel-plate calorimeter vessel of 79 mm diameter and 1.12 mm thick front and rear glass windows located 24 mm apart. Absorbed dose was measured with two sources with nominal air kerma strengths of 38 000 and 21 000 U, at source-detector separations ranging from 24.7 to 27.6 mm and irradiation times of 36.0 to 80.0 s. The preliminary measured dose rate per unit air kerma strength of (0.502±0.007) μGy/(s U) compares well with the TG-43 derived 0.505 μGy/(s U). This work shows that combined dose uncertainties of significantly less than 5% can be achieved with only modest modifications of current water calorimetry techniques and instruments. This work forms the basis of a potential future absolute dose to water standard for HDR 192Ir brachytherapy

  3. An absorbed dose to water standard for HDR 192Ir brachytherapy sources based on water calorimetry: numerical and experimental proof-of-principle.

    Science.gov (United States)

    Sarfehnia, Arman; Stewart, Kristin; Seuntjens, Jan

    2007-12-01

    Water calorimetry is an established technique for absorbed dose to water measurements in external beams. In this paper, the feasibility of direct absorbed dose measurements for high dose rate (HDR) iridium-192 (192Ir) sources using water calorimetry is established. Feasibility is determined primarily by a balance between the need to obtain sufficient signal to perform a reproducible measurement, the effect of heat loss on the measured signal, and the positioning uncertainty affecting the source-detector distance. The heat conduction pattern generated in water by the Nucletron microSelectron-HDR 192Ir brachytherapy source was simulated using COMSOL MULTIPHYSICS software. Source heating due to radiation self-absorption was calculated using EGSnrcMP. A heat-loss correction k(c) was calculated as the ratio of the temperature rise under ideal conditions to temperature rise under realistic conditions. The calorimeter setup used a parallel-plate calorimeter vessel of 79 mm diameter and 1.12 mm thick front and rear glass windows located 24 mm apart. Absorbed dose was measured with two sources with nominal air kerma strengths of 38 000 and 21 000 U, at source-detector separations ranging from 24.7 to 27.6 mm and irradiation times of 36.0 to 80.0 s. The preliminary measured dose rate per unit air kerma strength of (0.502 +/- 0.007) microGy/(s U) compares well with the TG-43 derived 0.505 microGy/(s U). This work shows that combined dose uncertainties of significantly less than 5% can be achieved with only modest modifications of current water calorimetry techniques and instruments. This work forms the basis of a potential future absolute dose to water standard for HDR 192Ir brachytherapy. PMID:18196821

  4. The use of TLDs for brachytherapy dosimetry

    International Nuclear Information System (INIS)

    Thermoluminescent dosimeters (TLDs) are routinely used to measure the dose around brachytherapy sources due to their small size and high precision. This work presents a concise overview of the use of LiF:Mg,Ti TLDs for brachytherapy dosimetry including the experimental procedures required to achieve high-precision measurements as well as new results regarding the intrinsic energy dependence with some of the commonly used brachytherapy sources. Equations to correct TLD light output to air kerma are outlined and a description of the method to determine the intrinsic energy dependence is presented. For the intrinsic energy dependence investigation, a review of previously published results is presented as well as new experimental results using 125I, 103Pd, 192Ir, and miniature x-ray brachytherapy sources at the University of Wisconsin Medical Radiation Research Center (UWMRRC). The results of these experiments are consistent with previous work and give valuable insight to investigators using TLDs for brachytherapy measurements. - Highlights: • Brachytherapy measurements with LiF:Mg,Ti TLDs performed. • Intrinsic energy dependence for several brachytherapy sources determined. • New LiF:Mg,Ti energy dependence results compared with previous data for x-ray beams. • Uncertainty of LiF:Mg,Ti TLD measurements reviewed

  5. Interstitial prostate brachytherapy. LDR-PDR-HDR

    International Nuclear Information System (INIS)

    The first comprehensive overview of interstitial brachytherapy for the management of local or locally advanced prostate cancer. Written by an interdisciplinary team who have been responsible for the successful GEC-ESTRO/EAU Teaching Course. Discusses in detail patient selection, the results of different methods, the role of imaging, and medical physics issues. Prostate brachytherapy has been the subject of heated debate among surgeons and the proponents of the various brachytherapy methods. This very first interdisciplinary book on the subject provides a comprehensive overview of innovations in low dose rate (LDR), high dose rate (HDR), and pulsed dose rate (PDR) interstitial brachytherapy for the management of local or locally advanced prostate cancer. In addition to detailed chapters on patient selection and the use of imaging in diagnostics, treatment guidance, and implantation control, background chapters are included on related medical physics issues such as treatment planning and quality assurance. The results obtained with the different treatment options and the difficult task of salvage treatment are fully discussed. All chapters have been written by internationally recognized experts in their fields who for more than a decade have formed the teaching staff responsible for the successful GEC-ESTRO/EAU Prostate Brachytherapy Teaching Course. This book will be invaluable in informing residents and others of the scientific background and potential of modern prostate brachytherapy. It will also prove a useful source of up-to-date information for those who specialize in prostate brachytherapy or intend to start an interstitial brachytherapy service.

  6. Verification of the dose from an Iridium-192 (192Ir) sealed source absorbed by an implantable cardioverter defibrillator (ICD) during uterine intracavitary brachytherapy

    International Nuclear Information System (INIS)

    The purpose of this study was to verify the dose absorbed by an implantable cardioverter defibrillator (ICD) from an 192Ir sealed source during uterine intracavitary brachytherapy, and to confirm its immunity to radiation effects. First, prior to treatment, the doses around the ICD position of an anthromorphic phantom were evaluated. Next, we also measured the dose at the ICD position using a fluorescent glass dosimeter and silicon diode dosimeter during the treatment of intracavitary brachytherapy of a patient implanted with an ICD. The results of the phantom study showed the dose percentage at the ICD location, 2 cm deep, to be 0.074% of the prescribed dose. The results of a treatment study similarly showed the dose, measured using a fluorescent glass dosimeter in the ICD position, to be 0.071% of the prescribed dose. During the application of the total prescribed dose, 30 Gy/5 fraction, the dose at the surface of the ICD position was estimated to be 21.2 mGy, well below the 1 Gy maximum recommended in the JASTRO guidelines. We regard dose verification and monitoring during treatment to be both necessary and useful in the treatment of individual cases. (author)

  7. Using LiF:Mg,Cu,P TLDs to estimate the absorbed dose to water in liquid water around an 192Ir brachytherapy source

    International Nuclear Information System (INIS)

    Purpose: The absorbed dose to water is the fundamental reference quantity for brachytherapy treatment planning systems and thermoluminescence dosimeters (TLDs) have been recognized as the most validated detectors for measurement of such a dosimetric descriptor. The detector response in a wide energy spectrum as that of an192Ir brachytherapy source as well as the specific measurement medium which surrounds the TLD need to be accounted for when estimating the absorbed dose. This paper develops a methodology based on highly sensitive LiF:Mg,Cu,P TLDs to directly estimate the absorbed dose to water in liquid water around a high dose rate 192Ir brachytherapy source. Methods: Different experimental designs in liquid water and air were constructed to study the response of LiF:Mg,Cu,P TLDs when irradiated in several standard photon beams of the LNE-LNHB (French national metrology laboratory for ionizing radiation). Measurement strategies and Monte Carlo techniques were developed to calibrate the LiF:Mg,Cu,P detectors in the energy interval characteristic of that found when TLDs are immersed in water around an192Ir source. Finally, an experimental system was designed to irradiate TLDs at different angles between 1 and 11 cm away from an 192Ir source in liquid water. Monte Carlo simulations were performed to correct measured results to provide estimates of the absorbed dose to water in water around the 192Ir source. Results: The dose response dependence of LiF:Mg,Cu,P TLDs with the linear energy transfer of secondary electrons followed the same variations as those of published results. The calibration strategy which used TLDs in air exposed to a standard N-250 ISO x-ray beam and TLDs in water irradiated with a standard137Cs beam provided an estimated mean uncertainty of 2.8% (k = 1) in the TLD calibration coefficient for irradiations by the 192Ir source in water. The 3D TLD measurements performed in liquid water were obtained with a maximum uncertainty of 11% (k = 1) found

  8. Neutron monitor calibration with 241AmBe(α, n), 252Cf , 252Cf+D2O and 238PuBe(α, n) used in dose evaluation near Linac

    International Nuclear Information System (INIS)

    The use of linear accelerators in Radiotherapy is becoming increasingly more common. From the Radiation Protection point of view, these instruments represent an advance relative to cobalt and caesium irradiators, mainly due to the absence of radioactive material. On the other hand, accelerators with energies over 10 MeV contaminate with neutrons the therapeutic beam. These neutrons are generated when high-energy photons interact with high-atomic-number materials such as tungsten and lead present in the accelerator itself. Photo-neutrons can also interact with other materials, present in the treatment room, consequently modifying the initial spectrum and causing other types of interactions which privilege the gamma capture. In this way, the measurement of the photo-neutron spectrum can be necessary in a radiometric survey. The present work carries through measurements in a linear accelerator of 15 MeV using three neutron area monitors calibrated using four radioactive sources: three ISO reference sources, 241AmBe (α, n), 252Cf (f, n) and 252Cf+D2O, and a 238PuBe(α, n) source. As the three first sources, this last one was standardized in the LMNRI/IRD manganese bath system. Comparison and evaluation of the response of these instruments were thereby made, analyzing whether the reading of the detectors using standard sources is adequate. In conclusion, the analysis of the response of neutron area calibrated detectors enable the use of them in an environment containing medical linear accelerator. (author)

  9. Brachytherapy applications and techniques

    CERN Document Server

    Devlin, Phillip M

    2015-01-01

    Written by the foremost experts in the field, this volume is a comprehensive text and practical reference on contemporary brachytherapy. The book provides detailed, site-specific information on applications and techniques of brachytherapy in the head and neck, central nervous system, breast, thorax, gastrointestinal tract, and genitourinary tract, as well as on gynecologic brachytherapy, low dose rate and high dose rate sarcoma brachytherapy, vascular brachytherapy, and pediatric applications. The book thoroughly describes and compares the four major techniques used in brachytherapy-intraca

  10. Dosimetric accuracy of a deterministic radiation transport based 192Ir brachytherapy treatment planning system. Part I: Single sources and bounded homogeneous geometries

    International Nuclear Information System (INIS)

    Purpose: The aim of this work is to validate a deterministic radiation transport based treatment planning system (TPS) for single 192Ir brachytherapy source dosimetry in homogeneous water geometries. Methods: TPS results were obtained using the deterministic radiation transport option of a BRACHYVISION v. 8.8 system for three characteristic source designs (VS2000, GMPlus HDR, and GMPlus PDR) with each source either centered in a 15 cm radius spherical water phantom, or positioned at varying distance away from the phantom center. Corresponding MC simulations were performed using the MCNPX code v.2.5.0 and source geometry models prepared using information provided by the manufacturers. Results: Comparison in terms of the AAPM TG-43 dosimetric formalism quantities, as well as dose rate distributions per unit air kerma strength with a spatial resolution of 0.1 cm, yielded close agreement between TPS and MC results for the sources centered in the phantom. Besides some regions close to the source longitudinal axes where discrepancies could be characterized as systematic, overall agreement for all three sources studied is comparable to the statistical (type A) uncertainty of MC simulations (1% at the majority of points in the geometry increasing to 2%-3% at points lying both away from the source center and close to the source longitudinal axis). A corresponding good agreement was also found between TPS and MC results for the sources positioned away from the phantom center. Conclusions: Results of this work attest the capability of the TPS to accurately account for the scatter conditions regardless of the size or shape of a given geometry of dosimetric interest, and the position of a source within it. This is important since, as shown in the literature and summarized also in this work, these factors could introduce a significant dosimetric effect that is currently ignored in clinical treatment planning. It is concluded that the implementation of the deterministic radiation

  11. Use of Monte Carlo Methods in brachytherapy

    International Nuclear Information System (INIS)

    The Monte Carlo method has become a fundamental tool for brachytherapy dosimetry mainly because no difficulties associated with experimental dosimetry. In brachytherapy the main handicap of experimental dosimetry is the high dose gradient near the present sources making small uncertainties in the positioning of the detectors lead to large uncertainties in the dose. This presentation will review mainly the procedure for calculating dose distributions around a fountain using the Monte Carlo method showing the difficulties inherent in these calculations. In addition we will briefly review other applications of the method of Monte Carlo in brachytherapy dosimetry, as its use in advanced calculation algorithms, calculating barriers or obtaining dose applicators around. (Author)

  12. Study and development of methodology for radioactive iodine fixation in polymeric substrate for manufacturing sources used in brachytherapy

    International Nuclear Information System (INIS)

    According global estimates of Globocan 2012 project of the International Agency for Research of Cancer, of the World Health Organization, there were 14,1 million new cases of cancer and a total of 8,2 million deaths from cancer. Also show that in 2030, the overall load will be 21,4 million new cases and 13,2 million cancer deaths. One of the prostate cancer therapy is brachytherapy, used in early and middle stages of the disease. It is made with the introduction of seeds with radioactive material within the tumor or in nearby regions, affecting the minimum surrounding tissues. The aim of this work is the study and developing the deposition of radioactive iodine on the polymeric substrate method, and an analysis relating the efficiency of the method to implementation in the laboratory of brachytherapy from IPEN. Iodine-125 is adsorbed on an epoxy resin solution. The objective of this study is to offer a new proposal for seeds. The results will give the data for the radiation protection and the procedures for radioactive waste management

  13. Dosimetric characterization of low dose rate Iridium 192 wires used in interstitial brachytherapy, produced by Brachytherapy Sources Laboratory the CTRS/IPEN/CNEN-SP, Brazil

    International Nuclear Information System (INIS)

    In this work they were some dosimetric parameters established by the dosimetry protocol AAPM TG-43 for the thread of 192Ir with the purpose of complementing the dosimetric specifications of an original source produced at the country. For so much quantities such as the constant of dose rate, A , function of radial dose, g(r), and anisotropy function, F(r,θ), they were experimentally determined and the geometry function, G(r,θ), it was calculated. Measurements with TLD of LiF, with dimensions of 1 mm X 1 mm X 1 mm, was made in a phantom made of 5 plates of solid water RW3 material with dimensions of 300 mm X 300 mm X 10 mm, where it was obtained values of dose rate for some radial distances of the source, between 10 and 100 mm, to for an angle of 90 deg, for g(r), and also for other angles between 0 deg and 180 deg for F(r,θ). Threads of 192Ir were studied in the lengths of 10 mm, 20 mm, 30 mm, 50 mm and 100 mm. The stored energy on the thermoluminescent dosimeters was integrated by means of a TLD reader Harshaw 2000 meantime into a cycle of thermal treatment to which the thermoluminescent dosimeters was submitted being, 400 C in an interval of time of 1 hour proceeded immediately for more 2 hours to 105 C, after this treatment the thermoluminescent dosimeters was irradiated; even so, before the reading the detectors was still warm to 105 deg C for 10 minutes. The constant of dose rate for the threads of 192Ir of 10 mm, 20 mm, 30 mm, 50 mm and 100 mm are (1,076 =- 3,7%); (0,931 =- 3,7%); (0,714 =- 3,7%); (0,589 =-3,7%) and (0,271 =- 3,7%) cGyh-1 U-1, respectively (1U = unit of kerma intensity in the air = 1mGy m2 h-1 = 1cGy cm2 h-1). The results obtained for g(r) and F(r,θ) have uncertainties of (=- 4,5%) and they are compared with values obtained by Monte Carlo simulation and also for other values presented in the literature. (author)

  14. Characterization of TLD-100 in powders for dosimetric quality control of 192 Ir sources used in brachytherapy of high dose rate

    International Nuclear Information System (INIS)

    The Secondary Standard Dosimetric at the National Institute of Nuclear Research (ININ) calibrated a lot of powdered TLD-100 (LiF:Mg,Ti) in terms of absorbed dose to water Dw for the energy of: 60Co, 137Cs, X rays of 250 and 50 kVp. Later on, it is carried out an interpolation of the calibration for the energy of the 192Ir. This calibration is part of a dosimetric quality control program, to solve the problems of traceability for the measurements carried out by the users of 192Ir sources employed in the treatments of High Dose Rate Brachytherapy (HDR) at the Mexican Republic. The calibrations of the radiation beams are made with the following protocols: IAEA TRS-398 for the 60Co for Dw, using a secondary standard ionization chamber PTW N30013 calibrated in Dw by the National Research Council (NRC, Canada). AAPM TG-43 for Dw in terms of the strength kerma Sk, calibrating this last one quantity for the 137Cs radioactive source, with a well chamber HDR 1000 PLUS traceable to the University of Wisconsin (US). AAPM TG-61 for X ray of 250 and 50 kVp for Dw start to Ka using field standard a Farmer chamber PTW 30001 traceable to K for the Central Laboratory of Electric Industries (CLEI, France). The calibration curves (CC) they built for the response of the powder TLD: RTLD vs Dw: For the energy of 60Co, 137Cs, X rays of 250 and 50 kVp. Fitting them with the least square method weighed by means of a polynomial of second grade that corrects the supra linearity of the response. iii. Each one of the curves was validated with a test by lack of fitting and for the Anderson Darling normality test, using the software MINITAB in both cases. iv. The sensibility factor (Fs) for each energy corresponds to the slope of the CC, v. The Fs for the two 192Ir sources used are interpolated: one for a Micro Selectron source and the other one a Vari Source source. Finally, a couple of capsules were sent to two hospitals that have the HDR Brachytherapy with sources of 192Ir and that

  15. Radiation Protection in Brachytherapy. Report of the SEFM Task Group on Brachytherapy

    International Nuclear Information System (INIS)

    This document presents the report of the Brachytherapy Task Group of the Spanish Society of Medical Physics. It is dedicated to the radiation protection aspects involved in brachytherapy. The aim of this work is to include the more relevant aspects related to radiation protection issues that appear in clinical practice, and for the current equipment in Spain. Basically this report focuses on the typical contents associated with high dose rate brachytherapy with 192Ir and 60Co sources, and permanent seed implants with 125I, 103Pd and 131Cs, which are the most current and widespread modalities. Ophthalmic brachytherapy (COMS with 125I, 106Ru, 90Sr) is also included due to its availability in a significant number of spanish hospitals. The purpose of this report is to assist to the medical physicist community in establishing a radiation protection program for brachytherapy procedures, trying to solve some ambiguities in the application of legal requirements and recommendations in clinical practice. (Author)

  16. Brachytherapy: Physical and clinical aspects

    International Nuclear Information System (INIS)

    Brachytherapy is a term used to describe the short distance treatment of cancer with radiation from small, encapsulated radionuclide sources. This type of treatment is given by placing sources directly into or near the volume to be treated. The dose is then delivered continuously, either over a short period of time (temporary implants) or over the lifetime of the source to a complete decay (permanent implants). Most common brachytherapy sources emit photons; however, in a few specialized situations b or neutron emitting sources are used. There are two main types of brachytherapy treatment: 1) Intracavitary, in which the sources are placed in body cavities close to the tumour volume; 2) Interstitial, in which the sources are implanted within the tumour volume. Intracavitary treatments are always temporary, of short duration, while interstitial treatments may be temporary or permanent. Temporary implants are inserted using either manual or remote afterloading procedures. Other, less common forms of brachytherapy treatments include surface plaque, intraluminal, intraoperative and intravascular source applications; for these treatments either g or b emitting sources are used. The physical advantage of brachytherapy treatments compared with external beam radiotherapy is the improved localized delivery of dose to the target volume of interest. The disadvantage is that brachytherapy can only be used in cases in which the tumour is well localized and relatively small. In a typical radiotherapy department about 10-20% of all radiotherapy patients are treated with brachytherapy. Several aspects must be considered when giving brachytherapy treatments. Of importance is the way in which the sources are positioned relative to the volume to be treated, and several different models have been developed over the past decades for this purpose. The advantage of using a well established model is that one benefits from the long experience associated with such models and that one can

  17. A practical implementation of the 2010 IPEM high dose rate brachytherapy code of practice for the calibration of {sup 192}Ir sources

    Energy Technology Data Exchange (ETDEWEB)

    Awunor, O A; Lecomber, A R; Richmond, N; Walker, C, E-mail: Onuora.Awunor@stees.nhs.uk [Regional Medical Physics Department, James Cook University Hospital, Marton Road, Middlesbrough, TS4 3BW (United Kingdom)

    2011-08-21

    This paper details a practical method for deriving the reference air kerma rate calibration coefficient for Farmer NE2571 chambers using the UK Institute of Physics and Engineering in Medicine (IPEM) code of practice for the determination of the reference air kerma rate for HDR {sup 192}Ir brachytherapy sources based on the National Physical Laboratory (NPL) air kerma standard. The reference air kerma rate calibration coefficient was derived using pressure, temperature and source decay corrected ionization chamber response measurements over three successive {sup 192}Ir source clinical cycles. A secondary standard instrument (a Standard Imaging 1000 Plus well chamber) and four tertiary standard instruments (one additional Standard Imaging 1000 Plus well chamber and three Farmer NE2571 chambers housed in a perspex phantom) were used to provide traceability to the NPL primary standard and enable comparison of performance between the chambers. Conservative and optimized estimates on the expanded uncertainties (k = 2) associated with chamber response, ion recombination and reference air kerma rate calibration coefficient were determined. This was seen to be 2.3% and 0.4% respectively for chamber response, 0.2% and 0.08% respectively for ion recombination and 2.6% and 1.2% respectively for the calibration coefficient. No significant change in ion recombination with source decay was observed over the duration of clinical use of the respective {sup 192}Ir sources.

  18. Intra coronary brachytherapy

    International Nuclear Information System (INIS)

    Despite the initial promise of vasculopathy intervention restenosis- a consequence of the (normal) would healing process-has emerged as a major problem. Angiographic restenosis has been reported in 40-60% of patients after successful P TCA. The basic mechanism of restenosis, (acute recoil, negative remodeling and neo intimal hyperplasia), are only partially counteracted by endovascular prosthetic devices (s tents). The rate of in-s tent restenosis, which is primarily caused by neo intimal hyperplasia due to the (micro) trauma of the arterial wall by the s tent struts, has been reduced to 18-32%. Ionizing (beta or gamma) radiations has been established as a potent treatment for malignant disorders. In recent years, there has also been increasing interest among clinicians in the management of benign lesions with radiation. Over the past several years, there has been a growing body of evidence that endovascular brachytherapy has a major impact on the biology of the restenosis. It must be underlined that understanding the biology and pathophysiology of restenosis and assessing various treatment options should preferably be a team effort, with the three gracesbeing interventional cardiologist, nuclear oncologist, and industrial partners. The vast amount of data in over 20000 patients from a wide range of randomized controlled trials, has shown that brachytherapy is the only effective treatment for in-s tent restenosis. We are learning more and more about how to improve brachytherapy. While the new coated s tents that we heard about today is fascinating and extremely promising, brachytherapy still has a very important place in difficult patients, such as those with total occlusions, osti al lesions, left main lesions, multivessel disease and diabetes. Regarding to above mentioned tips, we (a research team work, in the Nuclear Research Center Of the Atomic Energy Organization Of Iran), focused on synthesis and preparation of radioactive materials for use in I c-B T. We

  19. SU-E-T-102: Determination of Dose Distributions and Water-Equivalence of MAGIC-F Polymer Gel for 60Co and 192Ir Brachytherapy Sources

    Energy Technology Data Exchange (ETDEWEB)

    Quevedo, A; Nicolucci, P [University of Sao Paulo, Ribeirao Preto, SP (Brazil)

    2014-06-01

    Purpose: Analyse the water-equivalence of MAGIC-f polymer gel for {sup 60}Co and {sup 192}Ir clinical brachytherapy sources, through dose distributions simulated with PENELOPE Monte Carlo code. Methods: The real geometry of {sup 60} (BEBIG, modelo Co0.A86) and {sup 192}192Ir (Varian, model GammaMed Plus) clinical brachytherapy sources were modelled on PENELOPE Monte Carlo simulation code. The most probable emission lines of photons were used for both sources: 17 emission lines for {sup 192}Ir and 12 lines for {sup 60}. The dose distributions were obtained in a cubic water or gel homogeneous phantom (30 × 30 × 30 cm{sup 3}), with the source positioned in the middle of the phantom. In all cases the number of simulation showers remained constant at 10{sup 9} particles. A specific material for gel was constructed in PENELOPE using weight fraction components of MAGIC-f: wH = 0,1062, wC = 0,0751, wN = 0,0139, wO = 0,8021, wS = 2,58×10{sup −6} e wCu = 5,08 × 10{sup −6}. The voxel size in the dose distributions was 0.6 mm. Dose distribution maps on the longitudinal and radial direction through the centre of the source were used to analyse the water-equivalence of MAGIC-f. Results: For the {sup 60} source, the maximum diferences in relative doses obtained in the gel and water were 0,65% and 1,90%, for radial and longitudinal direction, respectively. For {sup 192}Ir, the maximum difereces in relative doses were 0,30% and 1,05%, for radial and longitudinal direction, respectively. The materials equivalence can also be verified through the effective atomic number and density of each material: Zef-MAGIC-f = 7,07 e .MAGIC-f = 1,060 g/cm{sup 3} and Zef-water = 7,22. Conclusion: The results showed that MAGIC-f is water equivalent, consequently being suitable to simulate soft tissue, for Cobalt and Iridium energies. Hence, gel can be used as a dosimeter in clinical applications. Further investigation to its use in a clinical protocol is needed.

  20. Influence of radioactive sources discretization in the Monte Carlo computational simulations of brachytherapy procedures: a case study on the procedures for treatment of prostate cancer; Influencia da discretizacao das fontes radioativas nas simulacoes computacionais Monte Carlo de procedimentos de braquiterapia: um estudo de caso sobre os procedimentos para tratamento do cancer de prostata

    Energy Technology Data Exchange (ETDEWEB)

    Barbosa, Antonio Konrado de Santana; Vieira, Jose Wilson [Instituto Federal de Educacao, Ciencia e Tecnologia (IFPE), Recife, PE (Brazil); Costa, Kleber Souza Silva [Faculdade Integrada de Pernambuco (FACIPE), Recife, PE (Brazil); Lima, Fernando Roberto de Andrade, E-mail: falima@cnen.gov.b [Centro Regional de Ciencias Nucleares do Nordeste (CRCN-NE/CNEN-PE), Recife, PE (Brazil)

    2011-07-01

    Radiotherapy computational simulation procedures using Monte Carlo (MC) methods have shown to be increasingly important to the improvement of cancer fighting strategies. One of the biases in this practice is the discretization of the radioactive source in brachytherapy simulations, which often do not match with a real situation. This study had the aim to identify and to measure the influence of radioactive sources discretization in brachytherapy MC simulations when compared to those that do not present discretization, using prostate brachytherapy with Iodine-125 radionuclide as model. Simulations were carried out with 108 events with both types of sources to compare them using EGSnrc code associated to MASH phantom in orthostatic and supine positions with some anatomic adaptations. Significant alterations were found, especially regarding bladder, rectum and the prostate itself. It can be concluded that there is a need to discretized sources in brachytherapy simulations to ensure its representativeness. (author)

  1. HDR endobronchial brachytherapy

    International Nuclear Information System (INIS)

    Introduction: This is a restrospective study to review the palliation rate, survival rate and complications of high dose rate (HDR) endobronchial brachytherapy in the treatment of airway obstruction of recurrent lung cancer or metastasis. Material and method: Between september 1992 and may 1995 it has been treated forty (40) patients with endobronchial lesions. 38 patients with unique endobronchial lesion and 2 patients with double lesions. 32 had primary lung carcinoma: 27 with epidermoid carcinoma (1 bilateral), 2 with adenocarcinoma, 1 with small cell carcinoma, 1 with undifferentiated carcinoma and 1 with primary double (adenocarcinoma and large cell carcinoma). 8 patients had endobronchial metastasis: 2 hypernefroma, 3 breast carcinoma, 1 colon cancer, 1 seminoma and 1 Ewing sarcoma. 33 patients were male (82.5%) and 7 female (17.5%). The treatment was carried out in three weekly fractions with a dose of 750 cGy per fraction at 1 cm from the source. An afterloaded equipment was used (microselectron HDR). The most frequent sites were: right main stem bronchus 9 patients (22.5%), left main stem bronchus 7 patients (17.5%), and right middle bronchus 5 patients (12.5%). Results and discussion: The endoscopic global response assessed after three weeks was of 70%. The symptomatic response was 95% hemoptysis control, 87% dysnea control, 80% obstructive pneumonia control and 70% cough control. The minimum follow up was one year. There were three cases of massive hemoptysis and three patients developed local recurrence (one received a second brachytherapy treatment). Conclusion: HDR brachytherapy offers an excellent long term palliation for any of the obstructing symptoms, being effective in more than 70% in patients with recurrence lung primary cancer or endobronchial metastasis with a low complication rate

  2. Evolution of different reaction methods resulting in the formation of AgI125 for use in brachytherapy sources

    International Nuclear Information System (INIS)

    Prostate cancer represents about 10% of all cases of cancer in the world. Brachytherapy has been extensively used in the early and intermediate stages of the illness. The radiotherapy method reduces the damage probability to surrounding healthy tissues. The present study compares several deposition methods of iodine-125 on silver substrate (seed core), in order to choose the most suitable one to be implemented at IPEN. Four methods were selected: method 1 (assay based on electrodeposition) which presented efficiency of 65.16%; method 2 (assay based on chemical reactions, developed by David Kubiatowicz) which presented efficiency of 70.80%; method 3 (chemical reaction based on the methodology developed by Dr. Maria Elisa Rostelato) which presented efficiency of 55.80%; new method developed by IPEN with 90.5% efficiency. Based on the results, the new method is the suggested one to be implemented. (authors)

  3. A revised dosimetric characterization of the model S700 electronic brachytherapy source containing an anode-centering plastic insert and other components not included in the 2006 model

    Energy Technology Data Exchange (ETDEWEB)

    Hiatt, Jessica R. [Department of Radiation Oncology, Rhode Island Hospital, The Warren Alpert Medical School of Brown University, Providence, Rhode Island 02903 (United States); Davis, Stephen D. [Department of Medical Physics, McGill University Health Centre, Montreal, Quebec H3G 1A4 (Canada); Rivard, Mark J., E-mail: mark.j.rivard@gmail.com [Department of Radiation Oncology, Tufts University School of Medicine, Boston, Massachusetts 02111 (United States)

    2015-06-15

    Purpose: The model S700 Axxent electronic brachytherapy source by Xoft, Inc., was characterized by Rivard et al. in 2006. Since then, the source design was modified to include a new insert at the source tip. Current study objectives were to establish an accurate source model for simulation purposes, dosimetrically characterize the new source and obtain its TG-43 brachytherapy dosimetry parameters, and determine dose differences between the original simulation model and the current model S700 source design. Methods: Design information from measurements of dissected model S700 sources and from vendor-supplied CAD drawings was used to aid establishment of an updated Monte Carlo source model, which included the complex-shaped plastic source-centering insert intended to promote water flow for cooling the source anode. These data were used to create a model for subsequent radiation transport simulations in a water phantom. Compared to the 2006 simulation geometry, the influence of volume averaging close to the source was substantially reduced. A track-length estimator was used to evaluate collision kerma as a function of radial distance and polar angle for determination of TG-43 dosimetry parameters. Results for the 50 kV source were determined every 0.1 cm from 0.3 to 15 cm and every 1° from 0° to 180°. Photon spectra in water with 0.1 keV resolution were also obtained from 0.5 to 15 cm and polar angles from 0° to 165°. Simulations were run for 10{sup 10} histories, resulting in statistical uncertainties on the transverse plane of 0.04% at r = 1 cm and 0.06% at r = 5 cm. Results: The dose-rate distribution ratio for the model S700 source as compared to the 2006 model exceeded unity by more than 5% for roughly one quarter of the solid angle surrounding the source, i.e., θ ≥ 120°. The radial dose function diminished in a similar manner as for an {sup 125}I seed, with values of 1.434, 0.636, 0.283, and 0.0975 at 0.5, 2, 5, and 10 cm, respectively. The radial dose

  4. SU-C-16A-01: In Vivo Source Position Verification in High Dose Rate (HDR) Prostate Brachytherapy Using a Flat Panel Imager: Initial Clinical Experience

    International Nuclear Information System (INIS)

    Purpose: We report our initial clinical experience with a novel position-sensitive source-tracking system based on a flat panel imager. The system has been trialled with 4 prostate HDR brachytherapy patients (8 treatment fractions) in this initial study. Methods: The flat panel imaging system was mounted under a customised carbon fibre couch top assembly (Figure 1). Three gold fiducial markers were implanted into the prostate of each patient at the time of catheter placement. X-ray dwell position markers were inserted into three catheters and a radiograph acquired to locate the implant relative to the imaging device. During treatment, as the HDR source dwells were delivered, images were acquired and processed to determine the position of the source in the patient. Source positions measured by the imaging device were compared to the treatment plan for verification of treatment delivery. Results: Measured dwell positions provided verification of relative dwell spacing within and between catheters, in the coronal plane. Measurements were typically within 2.0mm (0.2mm – 3.3mm, s.d. 0.8mm) of the planned positions over 60 dwells (Figure 2). Discrimination between larger dwell intervals and catheter differentiation were clear. This confirms important delivery attributes such as correct transfer tube connection, source step size, relative catheter positions and therefore overall correct plan selection and delivery. The fiducial markers, visible on the radiograph, provided verification of treatment delivery to the correct anatomical location. The absolute position of the dwells was determined by comparing the measured dwell positions with the x-ray markers from the radiograph, validating the programmed treatment indexer length. The total impact on procedure time was less than 5 minutes. Conclusion: The novel, noninvasive HDR brachytherapy treatment verification system was used clinically with minor impact on workflow. The system allows verification of correct treatment

  5. Proposal of a postal system for Ir-192 sources calibration used in high dose rate brachytherapy with LiF:Mn:Ti thermoluminescent dosemeters; Proposta de um sistema postal para a calibracao de fontes de {sup 192} Ir, utilizadas em braquiterapia de alta taxa de dose, com dosimetros termoluminescentes de LiF: Mn: Ti

    Energy Technology Data Exchange (ETDEWEB)

    Vieira, W.S.; Borges, J.C.; Almeida, C.E.V. [Instituto de Radioprotecao e Dosimetria. CNEN Caixa Postal 37750, 22780-160, Rio de Janeiro (Brazil)

    1998-12-31

    A proposal in order to improve the brachytherapy quality control and to allow postal intercomparison of Ir-192 sources used in high dose rate brachytherapy has been presented. The LiF: Mn: Ti (TLD 100) detector has been selected for such purpose. The experimental array and the TLDs irradiation and calibration techniques, at the treatment units, have been specified in the light of more recent methodology of Ir-192 calibration sources. (Author)

  6. The American Brachytherapy Society recommendations for low-dose-rate brachytherapy for carcinoma of the cervix

    International Nuclear Information System (INIS)

    Purpose: This report presents guidelines for using low-dose-rate (LDR) brachytherapy in the management of patients with cervical cancer. Methods: Members of the American Brachytherapy Society (ABS) with expertise in LDR brachytherapy for cervical cancer performed a literature review, supplemented by their clinical experience, to formulate guidelines for LDR brachytherapy of cervical cancer. Results: The ABS strongly recommends that radiation treatment for cervical carcinoma (with or without chemotherapy) should include brachytherapy as a component. Precise applicator placement is essential for improved local control and reduced morbidity. The outcome of brachytherapy depends, in part, on the skill of the brachytherapist. Doses given by external beam radiotherapy and brachytherapy depend upon the initial volume of disease, the ability to displace the bladder and rectum, the degree of tumor regression during pelvic irradiation, and institutional practice. The ABS recognizes that intracavitary brachytherapy is the standard technique for brachytherapy for cervical carcinoma. Interstitial brachytherapy should be considered for patients with disease that cannot be optimally encompassed by intracavitary brachytherapy. The ABS recommends completion of treatment within 8 weeks, when possible. Prolonging total treatment duration can adversely affect local control and survival. Recommendations are made for definitive and postoperative therapy after hysterectomy. Although recognizing that many efficacious LDR dose schedules exist, the ABS presents suggested dose and fractionation schemes for combining external beam radiotherapy with LDR brachytherapy for each stage of disease. The dose prescription point (point A) is defined for intracavitary insertions. Dose rates of 0.50 to 0.65 Gy/h are suggested for intracavitary brachytherapy. Dose rates of 0.50 to 0.70 Gy/h to the periphery of the implant are suggested for interstitial implant. Use of differential source activity or

  7. The role of brachytherapy in radiation and isotopes centre of Khartoum (RICK)

    CERN Document Server

    Ali, A M

    2000-01-01

    As there are many efforts devoted in order to manage the cancer, here the researcher handle one of these efforts that play a major part in treating the cancer internationally, it is a brachytherapy system. Brachytherapy was carried out mostly with radium sources, but recently some artificial sources are incorporated in this mode of treatment such as Cs-137, Ir-192, Au-198, P-32, Sr-90 and I-125. The research cover history of brachytherapy and radioactive sources used in, techniques of implementation, radiation protection and methods of brachytherapy dose calculation, as well as brachytherapy in radiation and isotopes centre in Khartoum.

  8. Comprehensive brachytherapy physical and clinical aspects

    CERN Document Server

    Baltas, Dimos; Meigooni, Ali S; Hoskin, Peter J

    2013-01-01

    Modern brachytherapy is one of the most important oncological treatment modalities requiring an integrated approach that utilizes new technologies, advanced clinical imaging facilities, and a thorough understanding of the radiobiological effects on different tissues, the principles of physics, dosimetry techniques and protocols, and clinical expertise. A complete overview of the field, Comprehensive Brachytherapy: Physical and Clinical Aspects is a landmark publication, presenting a detailed account of the underlying physics, design, and implementation of the techniques, along with practical guidance for practitioners. Bridging the gap between research and application, this single source brings together the technological basis, radiation dosimetry, quality assurance, and fundamentals of brachytherapy. In addition, it presents discussion of the most recent clinical practice in brachytherapy including prostate, gynecology, breast, and other clinical treatment sites. Along with exploring new clinical protocols, ...

  9. Microscopic description of Cf-252 cold fission yields

    CERN Document Server

    Mirea, M; Sandulescu, A

    2009-01-01

    We investigate the cold fission of 252Cf within the two center shell model to compute the potential energy surface. The fission yields are estimated by using the semiclassical penetration approach. It turns out that the inner cold valley of the total potential energy is strongly connected with Z=50 magic number. The agreement with experimental values is very much improved only by considering mass and charge asymmetry degrees of freedom. Thus, indeed cold fission of 252Cf is a Sn-like radioactivity, related the other two "magic radioactivities", namely alpha-decay and heavy-cluster decay, called also Pb-like radioactivity. This calculation provides the necessary theoretical confidence to estimate the penetration cross section in producing superheavy nuclei, by using the inverse fusion process.

  10. Microscopic description of Cf-252 cold fission yields

    OpenAIRE

    Mirea, M.; Delion, D. S.; Sandulescu, A.

    2009-01-01

    We investigate the cold fission of 252Cf within the two center shell model to compute the potential energy surface. The fission yields are estimated by using the semiclassical penetration approach. It turns out that the inner cold valley of the total potential energy is strongly connected with Z=50 magic number. The agreement with experimental values is very much improved only by considering mass and charge asymmetry degrees of freedom. Thus, indeed cold fission of 252Cf is a Sn-like radioact...

  11. Image guided Brachytherapy: The paradigm of Gynecologic and Partial Breast HDR Brachytherapy

    Science.gov (United States)

    Diamantopoulos, S.; Kantemiris, I.; Konidari, A.; Zaverdinos, P.

    2015-09-01

    High dose rate (HDR) brachytherapy uses high strength radioactive sources and temporary interstitial implants to conform the dose to target and minimize the treatment time. The advances of imaging technology enable accurate reconstruction of the implant and exact delineation of high-risk CTV and the surrounding critical structures. Furthermore, with sophisticated treatment planning systems, applicator devices and stepping source afterloaders, brachytherapy evolved to a more precise, safe and individualized treatment. At the Radiation Oncology Department of Metropolitan Hospital Athens, MRI guided HDR gynecologic (GYN) brachytherapy and accelerated partial breast irradiation (APBI) with brachytherapy are performed routinely. Contouring and treatment planning are based on the recommendations of the GEC - ESTRO Working group. The task of this presentation is to reveal the advantages of 3D image guided brachytherapy over 2D brachytherapy. Thus, two patients treated at our department (one GYN and one APBI) will be presented. The advantage of having adequate dose coverage of the high risk CTV and simultaneous low doses to the OARs when using 3D image- based brachytherapy will be presented. The treatment techniques, equipment issues, as well as implantation, imaging and treatment planning procedures will be described. Quality assurance checks will be treated separately.

  12. Verification and source-position error analysis of film reconstruction techniques used in the brachytherapy planning systems

    International Nuclear Information System (INIS)

    A method was presented that employs standard linac QA tools to verify the accuracy of film reconstruction algorithms used in the brachytherapy planning system. Verification of reconstruction techniques is important as suggested in the ESTRO booklet 8: ''The institution should verify the full process of any reconstruction technique employed clinically.'' Error modeling was also performed to analyze seed-position errors. The ''isocentric beam checker'' device was used in this work. It has a two-dimensional array of steel balls embedded on its surface. The checker was placed on the simulator couch with its center ball coincident with the simulator isocenter, and one axis of its cross marks parallel to the axis of gantry rotation. The gantry of the simulator was rotated to make the checker behave like a three-dimensional array of balls. Three algorithms used in the ABACUS treatment planning system: orthogonal film, 2-films-with-variable-angle, and 3-films-with-variable-angle were tested. After exposing and digitizing the films, the position of each steel ball on the checker was reconstructed and compared to its true position, which can be accurately calculated. The results showed that the error is dependent on the object-isocenter distance, but not the magnification of the object. The averaged errors were less than 1 mm within the tolerance level defined by Roueet al. [''The EQUAL-ESTRO audit on geometric reconstruction techniques in brachytherapy,'' Radiother. Oncol. 78, 78-83 (2006)]. However, according to the error modeling, the theoretical error would be greater than 2 mm if the objects were located more than 20 cm away from the isocenter with a 0.5 deg. reading error of the gantry and collimator angles. Thus, in addition to carefully performing the QA of the gantry and collimator angle indicators, it is suggested that the patient, together with the applicators or seeds inside, should be placed close to the isocenter as much as possible. This method could be used

  13. A generic high-dose rate {sup 192}Ir brachytherapy source for evaluation of model-based dose calculations beyond the TG-43 formalism

    Energy Technology Data Exchange (ETDEWEB)

    Ballester, Facundo, E-mail: Facundo.Ballester@uv.es [Department of Atomic, Molecular and Nuclear Physics, University of Valencia, Burjassot 46100 (Spain); Carlsson Tedgren, Åsa [Department of Medical and Health Sciences (IMH), Radiation Physics, Faculty of Health Sciences, Linköping University, Linköping SE-581 85, Sweden and Department of Medical Physics, Karolinska University Hospital, Stockholm SE-171 76 (Sweden); Granero, Domingo [Department of Radiation Physics, ERESA, Hospital General Universitario, Valencia E-46014 (Spain); Haworth, Annette [Department of Physical Sciences, Peter MacCallum Cancer Centre and Royal Melbourne Institute of Technology, Melbourne, Victoria 3000 (Australia); Mourtada, Firas [Department of Radiation Oncology, Helen F. Graham Cancer Center, Christiana Care Health System, Newark, Delaware 19713 (United States); Fonseca, Gabriel Paiva [Instituto de Pesquisas Energéticas e Nucleares – IPEN-CNEN/SP, São Paulo 05508-000, Brazil and Department of Radiation Oncology (MAASTRO), GROW, School for Oncology and Developmental Biology, Maastricht University Medical Center, Maastricht 6201 BN (Netherlands); Zourari, Kyveli; Papagiannis, Panagiotis [Medical Physics Laboratory, Medical School, University of Athens, 75 MikrasAsias, Athens 115 27 (Greece); Rivard, Mark J. [Department of Radiation Oncology, Tufts University School of Medicine, Boston, Massachusetts 02111 (United States); Siebert, Frank-André [Clinic of Radiotherapy, University Hospital of Schleswig-Holstein, Campus Kiel, Kiel 24105 (Germany); Sloboda, Ron S. [Department of Medical Physics, Cross Cancer Institute, Edmonton, Alberta T6G 1Z2, Canada and Department of Oncology, University of Alberta, Edmonton, Alberta T6G 2R3 (Canada); and others

    2015-06-15

    Purpose: In order to facilitate a smooth transition for brachytherapy dose calculations from the American Association of Physicists in Medicine (AAPM) Task Group No. 43 (TG-43) formalism to model-based dose calculation algorithms (MBDCAs), treatment planning systems (TPSs) using a MBDCA require a set of well-defined test case plans characterized by Monte Carlo (MC) methods. This also permits direct dose comparison to TG-43 reference data. Such test case plans should be made available for use in the software commissioning process performed by clinical end users. To this end, a hypothetical, generic high-dose rate (HDR) {sup 192}Ir source and a virtual water phantom were designed, which can be imported into a TPS. Methods: A hypothetical, generic HDR {sup 192}Ir source was designed based on commercially available sources as well as a virtual, cubic water phantom that can be imported into any TPS in DICOM format. The dose distribution of the generic {sup 192}Ir source when placed at the center of the cubic phantom, and away from the center under altered scatter conditions, was evaluated using two commercial MBDCAs [Oncentra{sup ®} Brachy with advanced collapsed-cone engine (ACE) and BrachyVision ACUROS{sup TM}]. Dose comparisons were performed using state-of-the-art MC codes for radiation transport, including ALGEBRA, BrachyDose, GEANT4, MCNP5, MCNP6, and PENELOPE2008. The methodologies adhered to recommendations in the AAPM TG-229 report on high-energy brachytherapy source dosimetry. TG-43 dosimetry parameters, an along-away dose-rate table, and primary and scatter separated (PSS) data were obtained. The virtual water phantom of (201){sup 3} voxels (1 mm sides) was used to evaluate the calculated dose distributions. Two test case plans involving a single position of the generic HDR {sup 192}Ir source in this phantom were prepared: (i) source centered in the phantom and (ii) source displaced 7 cm laterally from the center. Datasets were independently produced by

  14. Physical aspects of radioisotope brachytherapy

    International Nuclear Information System (INIS)

    The present report represents an attempt to provide, within a necessarily limited compass, an authoritative guide to all important physical aspects of the use of sealed gamma sources in radiotherapy. Within the report, reference is made wherever necessary to the more extensive but scattered literature on this subject. While this report attempts to cover all the physical aspects of radioisotope 'brachytherapy' it does not, of course, deal exhaustively with any one part of the subject. 384 refs, 3 figs, 6 tabs

  15. Clinical committee report: Recommendation for further clinical trials-patient studies

    International Nuclear Information System (INIS)

    The Cf-252 (Cf) neutron brachytherapy (NT) trials should continue to explore the feasibility of Cf-NT treatment of a variety of bulky human cancers. Results hitherto from the USA (Lexington), Japan, USSR, and England justify trials on a research basis. The term ''bulky'' is imprecise and in future studies should be specified by measurement. U.S. Department of Energy and other suppliers need to be advised to fabricate Cf-252 sources in more appropriate sizes, strengths and configurations for clinical therapy. Study of facility design and development should continue with special attention to: 1) treatment centers, 2) afterloading devices, 3) automated/robotics and other specialized equipment for handling Cf-252, 4) shields and shielding material, 5) controlled duration treatments, 6) necessary specialized equipment for conducting Cf-NT trials and 7) safety for personnel. In addition to the aforementioned, the report makes recommendations in several other areas such as doses and schedules, randomized trials, and records

  16. Characteristics of miniature electronic brachytherapy x-ray sources based on TG-43U1 formalism using Monte Carlo simulation techniques

    Energy Technology Data Exchange (ETDEWEB)

    Safigholi, Habib; Faghihi, Reza; Jashni, Somaye Karimi; Meigooni, Ali S. [Faculty of Engineering, Science and Research Branch, Islamic Azad University, Fars, 73481-13111, Persepolis (Iran, Islamic Republic of); Department of Nuclear Engineering and Radiation Research Center, Shiraz University, 71936-16548, Shiraz (Iran, Islamic Republic of); Shiraz University of Medical Sciences, 71348-14336, Shiraz (Iran, Islamic Republic of); Department of Radiation therapy, Comprehensive Cancer Center of Nevada, 3730 South Eastern Avenue, Las Vegas, Nevada 89169 (United States)

    2012-04-15

    Purpose: The goal of this study is to determine a method for Monte Carlo (MC) characterization of the miniature electronic brachytherapy x-ray sources (MEBXS) and to set dosimetric parameters according to TG-43U1 formalism. TG-43U1 parameters were used to get optimal designs of MEBXS. Parameters that affect the dose distribution such as anode shapes, target thickness, target angles, and electron beam source characteristics were evaluated. Optimized MEBXS designs were obtained and used to determine radial dose functions and 2D anisotropy functions in the electron energy range of 25-80 keV. Methods: Tungsten anode material was considered in two different geometries, hemispherical and conical-hemisphere. These configurations were analyzed by the 4C MC code with several different optimization techniques. The first optimization compared target thickness layers versus electron energy. These optimized thicknesses were compared with published results by Ihsan et al.[Nucl. Instrum. Methods Phys. Res. B 264, 371-377 (2007)]. The second optimization evaluated electron source characteristics by changing the cathode shapes and electron energies. Electron sources studied included; (1) point sources, (2) uniform cylinders, and (3) nonuniform cylindrical shell geometries. The third optimization was used to assess the apex angle of the conical-hemisphere target. The goal of these optimizations was to produce 2D-dose anisotropy functions closer to unity. An overall optimized MEBXS was developed from this analysis. The results obtained from this model were compared to known characteristics of HDR {sup 125}I, LDR {sup 103}Pd, and Xoft Axxent electronic brachytherapy source (XAEBS) [Med. Phys. 33, 4020-4032 (2006)]. Results: The optimized anode thicknesses as a function of electron energy is fitted by the linear equation Y ({mu}m) = 0.0459X (keV)-0.7342. The optimized electron source geometry is obtained for a disk-shaped parallel beam (uniform cylinder) with 0.9 mm radius. The TG-43

  17. Prostate cancer brachytherapy

    International Nuclear Information System (INIS)

    The transperineal brachytherapy with 125I/Pd103 seed implantation guided by transurethral ultrasound must be presented as therapeutical option of low urinary morbidity in patients with localized prostate cancer. The combined clinical staging - including Gleason and initial PSA - must be encouraged, for definition of a group of low risk and indication of exclusive brachytherapy. Random prospective studies are necessary in order to define the best role of brachytherapy, surgery and external beam radiation therapy

  18. Prototypes of phosphorus-32 sealed sources for use in Brachytherapy; Prototipo de fuente radiactiva de fosforo para uso medico en braquiterapia

    Energy Technology Data Exchange (ETDEWEB)

    Anaya Garro, Olgger; Vela Mora, Mariano; Revilla Silva, Angel Revilla [Instituto Peruano de Energia Nuclear (IPEN), Lima (Peru)]. E-mail: oanaya@ipen.gob.pe; mvela@ipen.gob.pe; arevilla@ipen.gob.pe

    2005-07-01

    It has developed prototypes of phosphorus-32 sealed sources for use in Brachytherapy. This one was made in two stages, at the first one, we designed and constructed the container (capsule), the filling system and the sealed system; at the second one, we made the irradiation of the capsules containing the 'target'. The prototypes was made of aluminum in cylindrical geometry. During the irradiation test was made using two different dimensions: one of 1 mm outer diameter and 1 cm length and another one of 0.8 mm outer diameter and 5 mm length. They were radiated in the core of the RP-10 research reactor, at 7.93 x10{sup 13} n/cm{sup 2}.s thermal neutron flux during 27 operation cycles. Activities of 144.53 MBq (3.91 mCi) and 107.67 MBq (2.91 mCi) was obtained for each case. This activities are adequate to restenosis and for some tumors treatment. We can observed that the capsules irradiated passed visual inspection in its physical integrity (leakage and geometry). It has been demonstrated, that the beta radiation for his minor power of penetration and its high interaction, causes major local damage to the malignant tissue, minimizing the damage of the healthy surrounding tissues. It has been advisable to use for the treatment of illnesses of the circulatory system and some tumors. At the present, the source of strontium-90 are the most beta ray source used, but of this one are obtained as fission product of uranium target, where valuable radioactive waste is generated, whereas if we were using phosphorus-32 that we propose, radioactive waste would not be generated since it would take place directly as sealed source, for reaction (n, {beta}). (author)

  19. SU-F-19A-05: Experimental and Monte Carlo Characterization of the 1 Cm CivaString 103Pd Brachytherapy Source

    International Nuclear Information System (INIS)

    Purpose: To determine the in-air azimuthal anisotropy and in-water dose distribution for the 1 cm length of the CivaString 103Pd brachytherapy source through measurements and Monte Carlo (MC) simulations. American Association of Physicists in Medicine Task Group No. 43 (TG-43) dosimetry parameters were also determined for this source. Methods: The in-air azimuthal anisotropy of the source was measured with a NaI scintillation detector and simulated with the MCNP5 radiation transport code. Measured and simulated results were normalized to their respective mean values and compared. The TG-43 dose-rate constant, line-source radial dose function, and 2D anisotropy function for this source were determined from LiF:Mg,Ti thermoluminescent dosimeter (TLD) measurements and MC simulations. The impact of 103Pd well-loading variability on the in-water dose distribution was investigated using MC simulations by comparing the dose distribution for a source model with four wells of equal strength to that for a source model with strengths increased by 1% for two of the four wells. Results: NaI scintillation detector measurements and MC simulations of the in-air azimuthal anisotropy showed that ≥95% of the normalized data were within 1.2% of the mean value. TLD measurements and MC simulations of the TG-43 dose-rate constant, line-source radial dose function, and 2D anisotropy function agreed to within the experimental TLD uncertainties (k=2). MC simulations showed that a 1% variability in 103Pd well-loading resulted in changes of <0.1%, <0.1%, and <0.3% in the TG-43 dose-rate constant, radial dose distribution, and polar dose distribution, respectively. Conclusion: The CivaString source has a high degree of azimuthal symmetry as indicated by the NaI scintillation detector measurements and MC simulations of the in-air azimuthal anisotropy. TG-43 dosimetry parameters for this source were determined from TLD measurements and MC simulations. 103Pd well-loading variability results in

  20. Optimization of deterministic transport parameters for the calculation of the dose distribution around a high dose-rate 192Ir brachytherapy source

    International Nuclear Information System (INIS)

    The goal of this work was to calculate the dose distribution around a high dose-rate 192Ir brachytherapy source using a multi-group discrete ordinates code and then to compare the results with a Monte Carlo calculated dose distribution. The unstructured tetrahedral mesh discrete ordinates code Attila version 6.1.1 was used to calculate the photon kerma rate distribution in water around the Nucletron microSelectron mHDRv2 source. MCNPX 2.5.c was used to compute the Monte Carlo water photon kerma rate distribution. Two hundred million histories were simulated, resulting in standard errors of the mean of less than 3% overall. The number of energy groups, Sn (angular order), Pn (scattering order), and mesh elements were varied in addition to the method of analytic ray tracing to assess their effects on the deterministic solution. Water photon kerma rate matrices were exported from both codes into an in-house data analysis software. This software quantified the percent dose difference distribution, the number of points within ±3% and ±5%, and the mean percent difference between the two codes. The data demonstrated that a 5 energy-group cross-section set calculated results to within 0.5% of a 15 group cross-section set. S12 was sufficient to resolve the solution in angle. P2 expansion of the scattering cross-section was necessary to compute accurate distributions. A computational mesh with 55 064 tetrahedral elements in a 30 cm diameter phantom resolved the solution spatially. An efficiency factor of 110 with the above parameters was realized in comparison to MC methods. The Attila code provided an accurate and efficient solution of the Boltzmann transport equation for the mHDRv2 source

  1. Post-stenting Intravascular Brachytherapy Trials on Hypercholesterolemic Rabbits Using 32P Liquid Sources: Implications for Prevention of In-Stent Restenosis

    International Nuclear Information System (INIS)

    Purpose: Liquid sources of radiation delivered in angioplasty balloons may be a convenient self-centering device used for prevention of in-stent restenosis. To test the effectiveness of this method an intravascular brachytherapy study was performed using 32P liquid sources in an animal model. Methods: The radial dose distribution around angioplasty balloons filled with solutions of Na2H32PO4 was calibrated by thermoluminescence dosimetry. The animal experiments were performed in rabbits with induced hypercholesterolemia. The balloons containing 32P were introduced into iliac arteries immediately after stent implantation. Estimated 7-49 Gy doses required 30-100 minirradiations. Radiation effects were evaluated by comparing the thickness of various components of the artery wall. Results:Doses of 7, 12, 16 or 49 Gy on the internal artery surface required 30-100 min of irradiation. The dose of 49 Gy at 'zero' distance corresponding to 16 Gy at 1.0 mm from the balloon surface reduced hypertrophy in every layer of the arterial wall: in the intima the cross-sectional areas were 0.13 versus 0.91 mm2, in the media were 0.5 versus 0.46 mm2 and in the adventitia were 0.04 versus 0.3 mm2 (p <0.05). A dose of 7 Gyat the balloon surface produced adverse irradiation effects: the intimal area of the artery was 2.087 versus 0.857 mm2, the medial area was 0.59 versus 0.282 mm2 and the adventitial area was 0.033 versus 0.209 mm2 in treated and control arteries, respectively.Conclusion: Application of a 49 Gy irradiation dose to the internal arterial surface effectively prevented in-stentrestenosis

  2. Evolution of dose distribution calculations in brachytherapy

    International Nuclear Information System (INIS)

    In this report the evolution of dose distribution calculations is revised in detail, considering the simplest case (a point source in free space) and the more complex situation of a real encapsulated line source embedded in a scattering medium. The most recent formalism to perform the dosimetry of interstitial brachytherapy sources is presented, where measured or measurable dose rates from actual sources in a tissue equivalent phantom are required as input data

  3. Dynamic rotating-shield brachytherapy

    International Nuclear Information System (INIS)

    Purpose: To present dynamic rotating shield brachytherapy (D-RSBT), a novel form of high-dose-rate brachytherapy (HDR-BT) with electronic brachytherapy source, where the radiation shield is capable of changing emission angles during the radiation delivery process.Methods: A D-RSBT system uses two layers of independently rotating tungsten alloy shields, each with a 180° azimuthal emission angle. The D-RSBT planning is separated into two stages: anchor plan optimization and optimal sequencing. In the anchor plan optimization, anchor plans are generated by maximizing the D90 for the high-risk clinical-tumor-volume (HR-CTV) assuming a fixed azimuthal emission angle of 11.25°. In the optimal sequencing, treatment plans that most closely approximate the anchor plans under the delivery-time constraint will be efficiently computed. Treatment plans for five cervical cancer patients were generated for D-RSBT, single-shield RSBT (S-RSBT), and 192Ir-based intracavitary brachytherapy with supplementary interstitial brachytherapy (IS + ICBT) assuming five treatment fractions. External beam radiotherapy doses of 45 Gy in 25 fractions of 1.8 Gy each were accounted for. The high-risk clinical target volume (HR-CTV) doses were escalated such that the D2cc of the rectum, sigmoid colon, or bladder reached its tolerance equivalent dose in 2 Gy fractions (EQD2 with α/β= 3 Gy) of 75 Gy, 75 Gy, or 90 Gy, respectively.Results: For the patients considered, IS + ICBT had an average total dwell time of 5.7 minutes/fraction (min/fx) assuming a 10 Ci192Ir source, and the average HR-CTV D90 was 78.9 Gy. In order to match the HR-CTV D90 of IS + ICBT, D-RSBT required an average of 10.1 min/fx more delivery time, and S-RSBT required 6.7 min/fx more. If an additional 20 min/fx of delivery time is allowed beyond that of the IS + ICBT case, D-RSBT and S-RSBT increased the HR-CTV D90 above IS + ICBT by an average of 16.3 Gy and 9.1 Gy, respectively.Conclusions: For cervical cancer patients, D

  4. Dynamic rotating-shield brachytherapy

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Yunlong [Department of Electrical and Computer Engineering, University of Iowa, 4016 Seamans Center, Iowa City, Iowa 52242 (United States); Flynn, Ryan T.; Kim, Yusung [Department of Radiation Oncology, University of Iowa, 200 Hawkins Drive, Iowa City, Iowa 52242 (United States); Yang, Wenjun [Department of Medical Physics, University of Wisconsin-Madison, 1111 Highland Avenue, Madison, Wisconsin 53705 (United States); Wu, Xiaodong [Department of Electrical and Computer Engineering, University of Iowa, 4016 Seamans Center, Iowa City, Iowa 52242 and Department of Radiation Oncology, University of Iowa, 200 Hawkins Drive, Iowa City, Iowa 52242 (United States)

    2013-12-15

    Purpose: To present dynamic rotating shield brachytherapy (D-RSBT), a novel form of high-dose-rate brachytherapy (HDR-BT) with electronic brachytherapy source, where the radiation shield is capable of changing emission angles during the radiation delivery process.Methods: A D-RSBT system uses two layers of independently rotating tungsten alloy shields, each with a 180° azimuthal emission angle. The D-RSBT planning is separated into two stages: anchor plan optimization and optimal sequencing. In the anchor plan optimization, anchor plans are generated by maximizing the D{sub 90} for the high-risk clinical-tumor-volume (HR-CTV) assuming a fixed azimuthal emission angle of 11.25°. In the optimal sequencing, treatment plans that most closely approximate the anchor plans under the delivery-time constraint will be efficiently computed. Treatment plans for five cervical cancer patients were generated for D-RSBT, single-shield RSBT (S-RSBT), and {sup 192}Ir-based intracavitary brachytherapy with supplementary interstitial brachytherapy (IS + ICBT) assuming five treatment fractions. External beam radiotherapy doses of 45 Gy in 25 fractions of 1.8 Gy each were accounted for. The high-risk clinical target volume (HR-CTV) doses were escalated such that the D{sub 2cc} of the rectum, sigmoid colon, or bladder reached its tolerance equivalent dose in 2 Gy fractions (EQD2 with α/β= 3 Gy) of 75 Gy, 75 Gy, or 90 Gy, respectively.Results: For the patients considered, IS + ICBT had an average total dwell time of 5.7 minutes/fraction (min/fx) assuming a 10 Ci{sup 192}Ir source, and the average HR-CTV D{sub 90} was 78.9 Gy. In order to match the HR-CTV D{sub 90} of IS + ICBT, D-RSBT required an average of 10.1 min/fx more delivery time, and S-RSBT required 6.7 min/fx more. If an additional 20 min/fx of delivery time is allowed beyond that of the IS + ICBT case, D-RSBT and S-RSBT increased the HR-CTV D{sub 90} above IS + ICBT by an average of 16.3 Gy and 9.1 Gy, respectively

  5. Divergence of Cs-137 sources fluence used in brachytherapy; Divergencia da fluencia de fontes de Cs-137 usadas em braquiterapia

    Energy Technology Data Exchange (ETDEWEB)

    Vianello, E.A.; Almeida, C.E. de [Laboratorio de Ciencias Radiologicas- LCR-DBB (UERJ). R. Sao Francisco Xavier, 524- Pav. HLC, sala 136 terreo- CEP 20.550- 013. Rio de Janeiro (Brazil)

    1998-12-31

    In this work the experimental determination of correction factor for fluence divergence (kln) of linear Cs-137 sources CDCS J4, with Farmer ionization chamber model 2571 in a central and perpendicular plan to source axis, for distances range from 1 to 7 cm., has been presented. The experimental results were compared to calculating by Kondo and Randolph (1960) isotropic theory and Bielajew (1990) anisotropic theory. (Author)

  6. Dose optimisation in single plane interstitial brachytherapy

    DEFF Research Database (Denmark)

    Tanderup, Kari; Hellebust, Taran Paulsen; Honoré, Henriette H;

    2006-01-01

    BACKGROUND AND PURPOSE: Brachytherapy dose distributions can be optimised       by modulation of source dwell times. In this study dose optimisation in       single planar interstitial implants was evaluated in order to quantify the       potential benefit in patients. MATERIAL AND METHODS: In 14...

  7. Dose calculation in brachytherapy with microcomputers

    International Nuclear Information System (INIS)

    The computer algorithms, that allow the calculation of brachytherapy doses and its graphic representation for implants, using programs developed for Pc microcomputers are presented. These algorithms allow to localized the sources in space, from their projection in radiographics images and trace isodose counter. (C.G.C.)

  8. Dosimetry characterization of $^{32}$P intravascular brachytherapy source wires using Monte Carlo codes PENELOPE and GEANT4

    CERN Document Server

    Torres, J; Almansa, J F; Guerrero, R; Lallena, A M; Torres, Javier; Buades, Manuel J.; Almansa, Julio F.; Guerrero, Rafael; Lallena, Antonio M.

    2003-01-01

    Monte Carlo calculations using the codes PENELOPE and GEANT4 have been performed to characterize the dosimetric parameters of the new 20 mm long catheter based $^{32}$P beta source manufactured by Guidant Corporation. The dose distribution along the transverse axis and the two dimensional dose rate table have been calculated. Also, the dose rate at the reference point, the radial dose function and the anisotropy function were evaluated according to the adapted TG-60 formalism for cylindrical sources. PENELOPE and GEANT4 codes were first verified against previous results corresponding to the old 27 mm Guidant $^{32}$P beta source. The dose rate at the reference point for the unsheathed 27 mm source in water was calculated to be $0.215 \\pm 0.001$ cGy s$^{-1}$ mCi$^{-1}$, for PENELOPE, and $0.2312 \\pm 0.0008$ cGy s$^{-1}$ mCi$^{-1}$, for GEANT4. For the unsheathed 20 mm source these values were $0.2908 \\pm 0.0009$ cGy s$^{-1}$ mCi$^{-1}$ and $0.311 \\pm 0.001$ cGy s$^{-1}$ mCi$^{-1}$, respectively. Also, a compar...

  9. An assessment of the radiological impact of brachytherapy application in Metro Manila hospitals

    International Nuclear Information System (INIS)

    One of the most important uses of radioactive sources in medicine is the application of brachytherapy technology. Brachytherapy is a method of radiation therapy where an encapsulated radioactive source delivers gamma or beta radiation into a tumor site. The paper describes different categories of brachytherapy applications involving manual insertion or afterloading and remote afterloading techniques. A list of five hospitals in Metro Manila practicing different techniques of brachytherapy are enumerated. Because of the widespread uses of radioactive sources in brachytherapy technology in medicine, inadequate control in its use had led to a number of incidents resulting to unnecessary exposure of radiation workers, patients and general public. This study was initiated to determine the radilogical hazards involved in brachytherapy applications. It presents contingency scenarios and their projected radiological consequences. (author). 7 refs., 2 tabs

  10. Study of photon angular distribution from a new Best 2300 series 125I source for interstitial brachytherapy

    International Nuclear Information System (INIS)

    125I seeds employed for permanent and temporary interstitial implants exhibit significant radiation fluence anisotropy due to self absorption in the marker and oblique filtration through the encapsulation jacket. A silver wire 125I seed (Model 6711), introduced in 1983 by 3M Company, failed to improve the photon distribution anisotropy. In addition to the known 125I photon spectrum, the new seed emitted two silver characteristic x-rays, lowering the mean photon energy from 28.4 to 27.4 keV. A double wall uniform thickness encapsulated 125I source, laser welded at one end, has been developed for clinical use. The source uses a carbon coated thin tungsten filament for enhanced radiographic visualization. Measurements made by NaI and intrinsic Ge detectors indicate that the 2300 series 125I source emits a pure 125I spectrum. The angular dependence of individual photon peaks and total photon spectrum as well as the corresponding anisotropy factors were measured. The 4π averaged anisotropy factor for the total radiation fluence is 0.92 compared to 0.87 for model 6711 seed. The dose distribution around the new 125I source in water is very isotropic. (author). 11 refs., 8 figs., 2 tabs

  11. Dosimetry in intravascular brachytherapy

    International Nuclear Information System (INIS)

    Among the cardiovascular diseases responsible for deaths in the adult population in almost all countries of the world, the most common is acute myocardial infarction, which generally occurs because of the occlusion of one or more coronary arteries. Several diagnostic techniques and therapies are being tested for the treatment of coronary artery disease. Balloon angioplasty has been a popular treatment which is less invasive than traditional 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).Recently, the idea of delivering high radiation doses to coronary arteries to avoid or delay restenosis has been suggested. 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 some patient populations. In order to study the radiation dosimetry in the patient and radiological protection for the attending staff for this therapy, radiation dose distributions for monoenergetic electrons and photons (at nine discrete energies) were calculated for blood vessels of diameter 0.15, o,30 and 0.45 cm with balloon and wire sources using the radiation transport code MCNP4B. Specific calculations were carried out for several candidate radionuclides as well. Two s tent sources (metallic prosthesis that put inside of patient's artery through angioplasty) employing 32 P are also simulated. Advantages and disadvantages of the various radionuclides and source geometries are discussed. The dosimetry developed here will aid in the realization of the benefits obtained in patients for this promising new technology. (author)

  12. Dosimetric impact of an 192Ir brachytherapy source cable length modeled using a grid-based Boltzmann transport equation solver

    International Nuclear Information System (INIS)

    Purpose: To evaluate the dose distributions of an 192Ir source (model VS2000) in homogeneous water geometry calculated using a deterministic grid-based Boltzmann transport equation solver (GBBS) in the commercial treatment planning system (TPS) (BRACHYVISION-ACUROS v8.8). Methods: Using percent dose differences (%ΔD), the GBBS (BV-ACUROS) was compared to the (1) published TG-43 data, (2) MCNPX Monte Carlo (MC) simulations of the 192Ir source centered in a 15 cm radius water sphere, and (3) TG-43 output from the TPS using vendor supplied (BV-TG43-vendor) and user extended (BV-TG43-extended) 2D anisotropy functions F(r,θ). BV-ACUROS assumes 1 mm of NiTi cable, while the TPS TG-43 algorithm uses data based on a 15 cm cable. MC models of various cable lengths were simulated. Results: The MC simulations resulted in >20% dose deviations along the cable for 1, 2, and 3 mm cable lengths relative to 15 cm. BV-ACUROS comparisons with BV-TG43-vendor and BV-TG43-extended yielded magnitude of differences, consistent with those seen in MC simulations. However, differences >20% extended further (θ≤10 deg.) when using the vendor supplied anisotropy function Fven(r,θ). These differences were also seen in comparisons of F(r,θ) derived from the TPS output. Conclusions: The results suggest that %ΔD near the cable region is larger than previously estimated. The spatial distribution of the dose deviation is highly dependent on the reference TG-43 data used to compare to GBBS. The differences observed, while important to realize, should not have an impact on clinical dosimetry in homogeneous water.

  13. The dosimetry of brachytherapy-induced erectile dysfunction

    International Nuclear Information System (INIS)

    There is emerging evidence that brachytherapy-induced erectile dysfunction (ED) is technique-related and may be minimized by careful attention to source placement. Herein, we review the relationship between radiation doses to the prostate gland/surrounding structures and the development of brachytherapy-induced ED. The permanent prostate brachytherapy literature was reviewed using MEDLINE searches to ensure completeness. Although the site-specific structure associated with brachytherapy-induced ED remains unknown, there is an increasing body of data implicating the proximal penis. With day 0 CT-based dosimetry, the dose to 50% (D50) and 25% (D25) of the bulb of the penis should be maintained below 40% and 60% mPD, respectively, while the crura D50 should be maintained below 28% mPD to maximize post-brachytherapy potency. To date, there is no data to suggest that either radiation doses to the neurovascular bundles or choice of isotope is associated with brachytherapy-induced ED, while conflicting data has been reported regarding radiation dose to the prostate and the use of supplemental external beam radiation therapy. Although the etiology of brachytherapy-induced ED is likely multifactorial, the available data supports the proximal penis as an important site-specific structure. Refinements in implant technique, including preplanning and intraoperative seed placement, will result in lower radiation doses to the proximal penis with potential improvement in potency preservation

  14. SU-E-T-548: Modeling of Breast IORT Using the Xoft 50 KV Brachytherapy Source and 316L Steel Rigid Shield

    International Nuclear Information System (INIS)

    Purpose: Xoft provides a set of 316L Stainless Steel Rigid Shields to be used with their 50 kV X-ray source for Breast IORT treatments. Modeling the different shield sizes in MCNP provides information to help make clinical decisions for selecting the appropriate shield size. Methods: The Xoft Axxent 50 kV Electronic Brachytherapy System has several applications in radiation therapy, one of which is treating cancer of the breast intraoperatively by placing the miniaturized X-ray tube inside an applicator balloon that is expanded to fill the lumpectomy bed immediately following tumor removal. The ribs, lung, and muscular chest wall are all regions at risk to receive undesired dose during the treatment. A Xoft 316L Stainless Steel Rigid Shield can be placed between the intracostal muscles of the chest wall and the remaining breast tissue near the balloon to attenuate the beam and protect these organs. These shields are provided in 5 different sizes, and the effects on dose to the surrounding tissues vary with shield size. MCNP was used to model this environment and tally dose rate to certain regions of interest. Results: The average rib dose rate calculated using 0cm (i.e., no shield), 3cm, and 5cm diameter shields were 26.89, 15.43, and 8.91 Gy/hr respectively. The maximum dose rates within the rib reached 94.74 Gy/hr, 53.56 Gy/hr, and 31.44 Gy/hr for the 0cm, 3cm, and 5cm cases respectively. The shadowing effect caused by the steel shields was seen in the 3-D meshes and line profiles. Conclusion: This model predicts a higher dose rate to the underlying rib region with the 3cm shield compared to the 5cm shield; it may be useful to select the largest possible diameter when choosing a shield size for a particular IORT patient. The ability to attenuate the beam to reduce rib dose was also confirmed. Research sponsored by Xoft Inc, a subsidiary of iCAD

  15. SU-E-T-548: Modeling of Breast IORT Using the Xoft 50 KV Brachytherapy Source and 316L Steel Rigid Shield

    Energy Technology Data Exchange (ETDEWEB)

    Burnside, W [Mountain View, CA (United States)

    2015-06-15

    Purpose: Xoft provides a set of 316L Stainless Steel Rigid Shields to be used with their 50 kV X-ray source for Breast IORT treatments. Modeling the different shield sizes in MCNP provides information to help make clinical decisions for selecting the appropriate shield size. Methods: The Xoft Axxent 50 kV Electronic Brachytherapy System has several applications in radiation therapy, one of which is treating cancer of the breast intraoperatively by placing the miniaturized X-ray tube inside an applicator balloon that is expanded to fill the lumpectomy bed immediately following tumor removal. The ribs, lung, and muscular chest wall are all regions at risk to receive undesired dose during the treatment. A Xoft 316L Stainless Steel Rigid Shield can be placed between the intracostal muscles of the chest wall and the remaining breast tissue near the balloon to attenuate the beam and protect these organs. These shields are provided in 5 different sizes, and the effects on dose to the surrounding tissues vary with shield size. MCNP was used to model this environment and tally dose rate to certain regions of interest. Results: The average rib dose rate calculated using 0cm (i.e., no shield), 3cm, and 5cm diameter shields were 26.89, 15.43, and 8.91 Gy/hr respectively. The maximum dose rates within the rib reached 94.74 Gy/hr, 53.56 Gy/hr, and 31.44 Gy/hr for the 0cm, 3cm, and 5cm cases respectively. The shadowing effect caused by the steel shields was seen in the 3-D meshes and line profiles. Conclusion: This model predicts a higher dose rate to the underlying rib region with the 3cm shield compared to the 5cm shield; it may be useful to select the largest possible diameter when choosing a shield size for a particular IORT patient. The ability to attenuate the beam to reduce rib dose was also confirmed. Research sponsored by Xoft Inc, a subsidiary of iCAD.

  16. Integer Programs for High Dose Rate Brachytherapy Needle and Dose Planning that Directly Optimize Clinical Objectives

    OpenAIRE

    Siauw, Ko-Ay Timmy

    2012-01-01

    High dose rate (HDR) brachytherapy is a radiation therapy for cancer in the prostate, cervix, breast, head, and neck, including other sites. In HDR brachytherapy, hollow needles are inserted or placed near the cancer site. Radiation is delivered to the patient by a radioactive source which is sequentially threaded through the needles. The dose distribution is controlled by altering the dwell times, the time spent at pre-defined positions on the needles.HDR brachytherapy has a 90\\% cancer-free...

  17. Biological effect of pulsed dose rate brachytherapy with stepping sources if short half-times of repair are present in tissues

    International Nuclear Information System (INIS)

    Purpose: To explore the possible increase of radiation effect in tissues irradiated by pulsed brachytherapy (PDR) for local tissue dose rates between those 'averaged over the whole pulse' and the instantaneous high dose rates close to the dwell positions. Increased effect is more likely for tissues with short half-times of repair of the order of a few minutes, similar to pulse durations. Methods and Materials: Calculations were done assuming the linear quadratic formula for radiation damage, in which only the dose-squared term is subject to exponential repair. The situation with two components of T(1(2)) is addressed. A constant overall time of 140 h and a constant total dose of 70 Gy were assumed throughout, the continuous low dose rate of 0.5 Gy/h (CLDR) providing the unitary standard effects for each PDR condition. Effects of dose rates ranging from 4 Gy/h to 120 Gy/h (HDR at 2 Gy/min) were studied, covering the gap in an earlier publication. Four schedules were examined: doses per pulse of 0.5, 1, 1.5, and 2 Gy given at repetition frequencies of 1, 2, 3, and 4 h, respectively, each with a range of assumed half-times of repair of 4 min to 1.5 h. Results are presented for late-responding tissues, the differences from CLDR being two or three times greater than for early-responding tissues and most tumors. Results: Curves are presented relating the ratio of increased biological effect (proportional to log cell kill) calculated for PDR relative to CLDR. Ratios as high as 1.5 can be found for large doses per pulse (2 Gy) if the half-time of repair in tissues is as short as a few minutes. The major influences on effect are dose per pulse, half-time of repair in tissue, and--when T(1(2)) is short--the instantaneous dose rate. Maximum ratios of PDR/CLDR occur when the dose rate is such that pulse duration is approximately equal to T(1(2)). As dose rate in the pulse is increased, a plateau of effect is reached, for most T(1(2))s, above 10 to 20 Gy/h, which is therefore

  18. Dosimetry in high dose rate endoluminal brachytherapy

    International Nuclear Information System (INIS)

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

  19. Comparison between methods for fixing radioactive iodine in silver substrate for manufacturing brachytherapy sources; Comparacao entre metodos de fixacao do iodo radioativo em substrato de prata para confeccao de fontes utilizadas em braquiterapia

    Energy Technology Data Exchange (ETDEWEB)

    Souza, Carla Daruich

    2012-07-01

    Among the different ways to treat prostate cancer, brachytherapy with iodine- 125 seeds is an option that provides good results and fewer side effects. In the present study several deposition methods of radioactive iodine in a silver substrate were compared in order to choose the most suitable alternative for the routine production to be implemented at IPEN's laboratory. The methodology used was chosen based on the available infrastructure and experience of the researchers present. Therefore, the {sup 131}I was used for testing (same chemical behavior as {sup 131}I). Four methods were selected: Method 1 (test based on electrodeposition method developed by D.Kubiatowicz) presented 65.16% efficiency; Method 2 (chemical reaction based on the method developed by D. Kubiatowicz - HCl) with the result of 70.80% efficiency; method 3 (chemical reaction based on the method developed by Dr. Maria Elisa Rostelato) with 55.80% efficiency; Method 4 (IQ-IPEN) resulted in 99% efficiency. Since this method has more radioactive material fixation (which represents virtually the entire cost of the seed), the final price is the cheapest. This method is the suggested one to be implemented in the IPEN's laboratory for brachytherapy sources production. Besides, the method is the fasted one. (author)

  20. Potential brachytherapy nuclides of future

    International Nuclear Information System (INIS)

    In the past there were relatively few radionuclides available for brachytherapy. But the situation is rapidly changing with the development of many new sources with properties that may be advantageous in certain clinical situations. In the choice of an acceptable, rather than an ideal radionuclide, it is important to consider the physical dose distribution, radiobiological effectiveness, ease of radiation protection, logistics and cost. Taking into account these factors, a number of radionuclides have been tried and more are being considered for specific type of applications. Presently, 137Cs is the most commonly used radionuclide for intracavitary therapy and 192Ir for interstitial therapy. 125I has more or less replaced 198Au for permanent implants. Clinical studies are being carried out to assess the feasibility of replacing 137Cs with 241Am for intracavitary applications and 125I with 103Pd and/or 169Yb for interstitial permanent implants. Other radionuclides being considered are 75Fe and 145Sm. Neutron induced brachytherapy is a new technique being tried to ensure complete radiation safety. (author). 1 tab

  1. Verification and analysis of the positioning of a source of brachytherapy high dose within an applicator gynecological interstitial fletcher Utrecht TC/RM; Verificacion y analysis del posicionamiento de una fuente de braquiterapia de alta tasa de dosis dentro de un aplicador ginecologico fletcher intersticial UTRECHT TC/RM

    Energy Technology Data Exchange (ETDEWEB)

    Panedo Cobos, J. M.; Garcia castejon, M. A.; Huertas Martinez, C.; Gomez-Tejedor Alonso, S.; Rincon Perez, M.; Luna Tirado, J.; Perez Casas, A. M.

    2013-07-01

    Applicators are guides that circulate and are located within the patient brachytherapy sources. Applicators can suffer mechanical deformations due to processes of sterilization or shock, which may result in that the source do not place within these very precise and coincides with the planned. In these cases the planned treatment deviate actually managed. The object of this study is to verify that the position of the source into the dispenser coincides with the planned position, with a procedure that is described. (Author)

  2. Dosimetric accuracy of a deterministic radiation transport based 192Ir brachytherapy treatment planning system. Part II: Monte Carlo and experimental verification of a multiple source dwell position plan employing a shielded applicator

    International Nuclear Information System (INIS)

    Purpose: The aim of this work is the dosimetric validation of a deterministic radiation transport based treatment planning system (BRACHYVISION v. 8.8, referred to as TPS in the following) for multiple 192Ir source dwell position brachytherapy applications employing a shielded applicator in homogeneous water geometries. Methods: TPS calculations for an irradiation plan employing seven VS2000 192Ir high dose rate (HDR) source dwell positions and a partially shielded applicator (GM11004380) were compared to corresponding Monte Carlo (MC) simulation results, as well as experimental results obtained using the VIP polymer gel-magnetic resonance imaging three-dimensional dosimetry method with a custom made phantom. Results: TPS and MC dose distributions were found in agreement which is mainly within ±2%. Considerable differences between TPS and MC results (greater than 2%) were observed at points in the penumbra of the shields (i.e., close to the edges of the ''shielded'' segment of the geometries). These differences were experimentally verified and therefore attributed to the TPS. Apart from these regions, experimental and TPS dose distributions were found in agreement within 2 mm distance to agreement and 5% dose difference criteria. As shown in this work, these results mark a significant improvement relative to dosimetry algorithms that disregard the presence of the shielded applicator since the use of the latter leads to dosimetry errors on the order of 20%-30% at the edge of the ''unshielded'' segment of the geometry and even 2%-6% at points corresponding to the potential location of the target volume in clinical applications using the applicator (points in the unshielded segment at short distances from the applicator). Conclusions: Results of this work attest the capability of the TPS to accurately account for the scatter conditions and the increased attenuation involved in HDR brachytherapy applications employing multiple source dwell positions and partially

  3. Dosimetric accuracy of a deterministic radiation transport based {sup 192}Ir brachytherapy treatment planning system. Part II: Monte Carlo and experimental verification of a multiple source dwell position plan employing a shielded applicator

    Energy Technology Data Exchange (ETDEWEB)

    Petrokokkinos, L.; Zourari, K.; Pantelis, E.; Moutsatsos, A.; Karaiskos, P.; Sakelliou, L.; Seimenis, I.; Georgiou, E.; Papagiannis, P. [Medical Physics Laboratory, Medical School, University of Athens, 75 Mikras Asias, 115 27 Athens (Greece); Department of Physics, Nuclear and Particle Physics Section, University of Athens, Panepistimioupolis, Ilisia, 157 71 Athens (Greece); Medical Physics Laboratory, Medical School, Democritus University of Thrace, 2nd Building of Preclinical Section, University Campus, Alexandroupolis 68100 (Greece); Medical Physics Laboratory, Medical School, University of Athens, 75 Mikras Asias, 115 27 Athens (Greece)

    2011-04-15

    Purpose: The aim of this work is the dosimetric validation of a deterministic radiation transport based treatment planning system (BRACHYVISION v. 8.8, referred to as TPS in the following) for multiple {sup 192}Ir source dwell position brachytherapy applications employing a shielded applicator in homogeneous water geometries. Methods: TPS calculations for an irradiation plan employing seven VS2000 {sup 192}Ir high dose rate (HDR) source dwell positions and a partially shielded applicator (GM11004380) were compared to corresponding Monte Carlo (MC) simulation results, as well as experimental results obtained using the VIP polymer gel-magnetic resonance imaging three-dimensional dosimetry method with a custom made phantom. Results: TPS and MC dose distributions were found in agreement which is mainly within {+-}2%. Considerable differences between TPS and MC results (greater than 2%) were observed at points in the penumbra of the shields (i.e., close to the edges of the ''shielded'' segment of the geometries). These differences were experimentally verified and therefore attributed to the TPS. Apart from these regions, experimental and TPS dose distributions were found in agreement within 2 mm distance to agreement and 5% dose difference criteria. As shown in this work, these results mark a significant improvement relative to dosimetry algorithms that disregard the presence of the shielded applicator since the use of the latter leads to dosimetry errors on the order of 20%-30% at the edge of the ''unshielded'' segment of the geometry and even 2%-6% at points corresponding to the potential location of the target volume in clinical applications using the applicator (points in the unshielded segment at short distances from the applicator). Conclusions: Results of this work attest the capability of the TPS to accurately account for the scatter conditions and the increased attenuation involved in HDR brachytherapy applications

  4. American Brachytherapy Society (ABS) recommendations for transperineal permanent brachytherapy of prostate cancer

    International Nuclear Information System (INIS)

    Purpose/Objective: To develop and disseminate the American Brachytherapy Society (ABS) recommendations for the clinical quality assurance and guidelines of permanent transperineal prostate brachytherapy with 125I or 103Pd. Methods and Materials: The ABS formed a committee of experts in prostate brachytherapy to develop consensus guidelines through a critical analysis of published data supplemented by their clinical experience. The recommendations of the panels were reviewed and approved by the Board of Directors of the ABS. Results: Patients with high probability of organ-confined disease are appropriately treated with brachytherapy alone. Brachytherapy candidates with a significant risk of extraprostatic extension should be treated with supplemental external beam radiation therapy (EBRT). Patient selection guidelines were developed. Dosimetric planning of the implant should be carried out for all patients before seed insertion. A modified peripheral loading is preferred. The AAPM TG-43 recommendations requiring a change in prescription dose for 125I sources should be universally implemented. The recommended prescription doses for monotherapy are 145 Gy for 125I and 115-120 Gy for 103Pd. The corresponding boost doses (after 40-50 Gy EBRT) are 100-110 Gy and 80-90 Gy, respectively. Clinical evidence to guide selection of radionuclide (103Pd or 125I) is lacking. Post implant dosimetry and evaluation must be performed on all patients. It is suggested that the dose that covers 90% (D90) and 100% (D100) of the prostate volume and the percentage of the prostate volume receiving the prescribed dose (V100) be obtained from a dose-volume histogram (DVH) and reported. Conclusion: Guidelines for appropriate patient selection, dose reporting, and improved quality of permanent prostate brachytherapy are presented. These broad recommendations are intended to be technical and advisory in nature, but the ultimate responsibility for the medical decisions rests with the treating

  5. Restenosis: Intracoronary Brachytherapy.

    Science.gov (United States)

    Drachman, Douglas E.; Simon, Daniel I.

    2002-04-01

    Though interventional strategies have revolutionized the management of patients with symptomatic coronary artery disease, in-stent restenosis has emerged as the single most important limitation of long-term success following percutaneous coronary intervention. Once present, in-stent restenosis is extraordinarily difficult to treat, with conventional revascularization techniques failing in 50% to 80% of patients. Intracoronary radiation, or brachytherapy, targets cellular proliferation within the culprit neointima. Clinical trials have demonstrated that brachytherapy is a highly effective treatment for in-stent restenosis, reducing angiographic restenosis by 50% to 60% and the need for target vessel revascularization by 40% to 50%. The benefits of intracoronary brachytherapy may be particularly pronounced in certain patient subgroups (eg, those with diabetes, long lesions, or lesions in saphenous vein bypass grafts), but comes at the cost of an increased rate of late stent thrombosis and the need for extended antiplatelet therapy. The role of brachytherapy in the arsenal of the interventional cardiologist will continue to evolve, particularly in light of the unprecedented recent advances with the use of drug-eluting stents for restenosis prevention. PMID:11858773

  6. Magnetite nanoparticles for nonradionuclide brachytherapy1

    OpenAIRE

    Safronov, Victor; Sozontov, Evgeny; Polikarpov, Mikhail

    2015-01-01

    Magnetite nanoparticles possess several properties that can make them useful for targeted delivery of radiation to tumors for the purpose of brachytherapy. Such particles are biodegradable and magnetic and can emit secondary radiation when irradiated by an external source. In this work, the dose distribution around a magnetite particle of 10 nm diameter being irradiated by monochromatic X-rays with energies in the range 4–60 keV is calculated.

  7. Development of a Brachytherapy Software Nomogram Equivalent

    International Nuclear Information System (INIS)

    The main objective of this project is developing a software nomogram equivalent. A nomogram is a graph typically comprised of three parallel lines. Each of the lines is graduated for a different variable, often in a non-linear scale. The lines are oriented in such a manner that if a straight line is drawn connecting two of the three variables, the value of the third variable is uniquely determined by the intersection of the connecting line and the graduated line of the third variable. The value of the third variable is determined by reading the graduated scale at the point of intersection. A nomogram as applied in brachytherapy is used for determining the required amount of radioactive material to be implanted in a diseased site. A typical brachytherapy nomogram relates the average dimension of a site, the air kerma strength per source and the number of sources required for yielding a therapeutic radiation dose to the site. More sophisticated nomograms also provide scales for recommending source and needle spacings. For decades the nomogram has been clinically employed as a brachytherapy treatment planning tool. Imaging modalities such as CT and ultrasound ushered in modern image-based brachytherapy treatment planning. These modern imaging techniques dramatically advanced the state of the art of brachytherapy, often obviating the use of nomograms. Although the routine use of nomograms has decreased, there are clinical situations where nomograms still prove useful for brachytherapy treatment planning. Often times the dimensions of a tumor or tumor bed are not known prior to surgery and delineated images of the site are not available. In such situations the tumor dimensions can be measured in the OR and a nomogram applied for rapid treatment planning. By definition a nomogram is a graphical tool, which is fixed and cannot be modified. Differences of opinion and treatment philosophies exist among physicians and institutions. These varying approaches can lead to

  8. Development of a multi-electrode extrapolation chamber as a prototype of a primary standard for the realization of the unit of the absorbed dose to water for beta brachytherapy sources

    CERN Document Server

    Bambynek, M

    2002-01-01

    The prototype of a primary standard has been developed, built and tested, which enables the realization of the unit of the absorbed dose to water for beta brachytherapy sources. In the course of the development of the prototype, the recommendations of the American Association of Physicists in Medicine (AAPM) Task Group 60 (TG60) and the Deutsche Gesellschaft fuer Medizinische Physik (DGMP) Arbeitskreis 18 (AK18) were taken into account. The prototype is based on a new multi-electrode extrapolation chamber (MEC) which meets, in particular, the requirements on high spatial resolution and small uncertainty. The central part of the MEC is a segmented collecting electrode which was manufactured in the clean room center of PTB by means of electron beam lithography on a wafer. A precise displacement device consisting of three piezoelectric macrotranslators has been incorporated to move the wafer collecting electrode against the entrance window. For adjustment of the wafer collecting electrode parallel to the entranc...

  9. Imaging method for monitoring delivery of high dose rate brachytherapy

    Science.gov (United States)

    Weisenberger, Andrew G; Majewski, Stanislaw

    2012-10-23

    A method for in-situ monitoring both the balloon/cavity and the radioactive source in brachytherapy treatment utilizing using at least one pair of miniature gamma cameras to acquire separate images of: 1) the radioactive source as it is moved in the tumor volume during brachytherapy; and 2) a relatively low intensity radiation source produced by either an injected radiopharmaceutical rendering cancerous tissue visible or from a radioactive solution filling a balloon surgically implanted into the cavity formed by the surgical resection of a tumor.

  10. Calibration of a {sup 19} {sup 2}Ir source for high dose brachytherapy using various techniques; Calibracion de una fuente de {sup 192} Ir para braquiterapia de alta tasa de dosis mediante diversas tecnicas

    Energy Technology Data Exchange (ETDEWEB)

    Montilla Prieto, Tedicel C., E-mail: tcdicel@gmaiLcam [Instituto de Oncologia Dr. Miguel Perez Carreno, Barbula (Venezuela, Bolivarian Republic of). Departamento de Fisica y Dosimetria; Padron Rivero, Alvaro D., E-mail: alvarodpadronr@yahoo.com.ve [Universidad de Carabobo, Barbula (Venezuela, Bolivarian Republic of). Facultad de Ciencias de la Salud. Departamento de Ciencias Fisiologicas

    2013-10-01

    In this research we studied three experimental procedures for calibration of a source of {sup 192}Ir to high dose rate for clinical brachytherapy use, and thus were compared and analysis of the advantages and disadvantages of each. For this study we quantified the value of the current kerma rate reference in air by three procedures: source calibration using a well chamber, with an cylindrical ionization chamber in air, and a cylindrical ionization chamber on a phantom, and this magnitude was compared with the value provided by the manufacturer of the source and thereby obtaining the deviation corresponding . Thus, it was found that the deviation corresponding to the source calibration making use of a well chamber, remained within tolerance, while the cylindrical ionization chamber in air and on phantom exceeded the standards established in some documents. However, although both the measurement in air and in the phantom are the procedures for the final calibration source, these can be used to verify that the delivered dose are in tolerance.

  11. Radiochromic dye film studies for brachytherapy applications.

    Science.gov (United States)

    Martínez-Dávalos, A; Rodríguez-Villafuerte, M; Díaz-Perches, R; Arzamendi-Pérez, S

    2002-01-01

    Commercial radiochromic dye films have been used in recent years to quantify absorbed dose in several medical applications. In this study we present the characterisation of the GafChromic MD-55-2 dye film, a double sensitive layer film suitable for photon irradiation in brachytherapy applications. Dose measurements were carried out with a low dose rate 137Cs brachytherapy source, which produces very steep dose gradients in its vicinity, and therefore requires the capability of producing high spatial resolution isodose curves. Quantification of the dose rate in water per unit air kerma strength was obtained using a high-resolution transmission commercial scanner (Agfa DuoScan T1200 with the capability of digitising up to 600 x 1200 pixels per inch using 36 bits per pixel, together with optical density measurements. The Monte Carlo calculations and experimental measurements compared well in the 0-50 Gy dose interval used in this study. PMID:12382798

  12. Radiochromic dye film studies for brachytherapy applications

    Energy Technology Data Exchange (ETDEWEB)

    Martinez-Davalos, A.; Rodriguez-Villafuerte, M.; Diaz-Perches, R.; Arzamendi-Perez, S

    2002-07-01

    Commercial radiochromic dye films have been used in recent years to quantify absorbed dose in several medical applications. In this study we present the characterisation of the GafChromic MD-55-2 dye film, a double sensitive layer film suitable for photon irradiation in brachytherapy applications. Dose measurements were carried out with a low dose rate {sup 137}Cs brachytherapy source, which produces very steep dose gradients in its vicinity, and therefore requires the capability of producing high spatial resolution isodose curves. Quantification of the dose rate in water per unit air kerma strength was obtained using a high-resolution transmission commercial scanner (Agfa DuoScan T1200) with the capability of digitising up to 600 x 1200 pixels per inch using 36 bits per pixel, together with optical density measurements. The Monte Carlo calculations and experimental measurements compared well in the 0-50 Gy dose interval used in this study. (author)

  13. Radiochromic dye film studies for brachytherapy applications

    International Nuclear Information System (INIS)

    Commercial radiochromic dye films have been used in recent years to quantify absorbed dose in several medical applications. In this study we present the characterisation of the GafChromic MD-55-2 dye film, a double sensitive layer film suitable for photon irradiation in brachytherapy applications. Dose measurements were carried out with a low dose rate 137Cs brachytherapy source, which produces very steep dose gradients in its vicinity, and therefore requires the capability of producing high spatial resolution isodose curves. Quantification of the dose rate in water per unit air kerma strength was obtained using a high-resolution transmission commercial scanner (Agfa DuoScan T1200) with the capability of digitising up to 600 x 1200 pixels per inch using 36 bits per pixel, together with optical density measurements. The Monte Carlo calculations and experimental measurements compared well in the 0-50 Gy dose interval used in this study. (author)

  14. The evolution of brachytherapy treatment planning

    International Nuclear Information System (INIS)

    Brachytherapy is a mature treatment modality that has benefited from technological advances. Treatment planning has advanced from simple lookup tables to complex, computer-based dose-calculation algorithms. The current approach is based on the AAPM TG-43 formalism with recent advances in acquiring single-source dose distributions. However, this formalism has clinically relevant limitations for calculating patient dose. Dose-calculation algorithms are being developed based on Monte Carlo methods, collapsed cone, and solving the linear Boltzmann transport equation. In addition to improved dose-calculation tools, planning systems and brachytherapy treatment planning will account for material heterogeneities, scatter conditions, radiobiology, and image guidance. The AAPM, ESTRO, and other professional societies are working to coordinate clinical integration of these advancements. This Vision 20/20 article provides insight into these endeavors.

  15. The evolution of brachytherapy treatment planning

    Energy Technology Data Exchange (ETDEWEB)

    Rivard, Mark J.; Venselaar, Jack L. M.; Beaulieu, Luc [Department of Radiation Oncology, Tufts University School of Medicine, Boston, Massachusetts 02111 (United States); Department of Medical Physics, Instituut Verbeeten, P.O. Box 90120, 5000 LA Tilburg (Netherlands); Departement de Radio-Oncologie et Centre de Recherche en Cancerologie de l' Universite Laval, Centre Hospitalier Universitaire de Quebec, 11 Cote du Palais, Quebec, Quebec G1R 2J6 (Canada) and Departement de Physique, de Genie Physique et d' Optique, Universite Laval, Quebec, Quebec G1K 7P4 (Canada)

    2009-06-15

    Brachytherapy is a mature treatment modality that has benefited from technological advances. Treatment planning has advanced from simple lookup tables to complex, computer-based dose-calculation algorithms. The current approach is based on the AAPM TG-43 formalism with recent advances in acquiring single-source dose distributions. However, this formalism has clinically relevant limitations for calculating patient dose. Dose-calculation algorithms are being developed based on Monte Carlo methods, collapsed cone, and solving the linear Boltzmann transport equation. In addition to improved dose-calculation tools, planning systems and brachytherapy treatment planning will account for material heterogeneities, scatter conditions, radiobiology, and image guidance. The AAPM, ESTRO, and other professional societies are working to coordinate clinical integration of these advancements. This Vision 20/20 article provides insight into these endeavors.

  16. Preparation and determination of kerma for Iridium 192 sources of low dose rate for brachytherapy; Preparacion y determinacion del kerma de fuentes de iridio-192 de baja tasa de dosis para braquiterapia

    Energy Technology Data Exchange (ETDEWEB)

    Tendilla, J.I.; Tovar M, V.; Mitsoura, E.; Aguilar H, F.; Alanis M, J. [Instituto Nacional de Investigaciones Nucleares, C.P. 52045-1, Salazar, Esrado de Mexico, D.F. (Mexico)

    2000-07-01

    The practice of Brachytherapy with Iridium-192 sources of low dose rate (0.4 - 0.8 Gy/h) is a technique used in the treatment of diverse illnesses. in this work the preparation, quality control and calibration are presented in terms of kerma in air of Iridium-192 using as target these recycled Iridium-Platinum wires. The targets were obtained as decayed sources of different radio therapeutical centers in the country and they were characterized by Scanning electron microscopy in order to determine their chemical composition. Subsequently it was developed an experimental design to establish the effect of neutron flux, geometrical array and irradiation time over the activity and percentage of the sources homogeneity. The homogeneity was determined by auto radiography and by Gamma spectroscopy. Once the optimal irradiation conditions were established, it is determined the apparent activity and kerma in air using a well type ionization chamber with traceability to a primary laboratory. Iridium-192 sources were obtained with an average homogeneity 96 %, apparent activity 282.129 {+-} 0.531 M Bq and kerma in air 0.03200 {+-} 0.00006 m Gy m/h A. (Author)

  17. Glass microspheres for brachytherapy

    International Nuclear Information System (INIS)

    We developed the capacity to produce glass microspheres containing in their structure one or more radioactive isotopes useful for brachytherapy. We studied the various facts related with their production: (Rare earth) alumino silicate glass making, glass characterization, microspheres production, nuclear activation through (n,γ) nuclear reactions, mechanical characterization before and after irradiation. Corrosion tests in simulated human plasma and mechanical properties characterization were done before and after irradiation. (author)

  18. Dosimetric calculus in intravascular brachytherapy

    International Nuclear Information System (INIS)

    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. Two stent sources employing 32P are also simulated. 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)

  19. Salvage Brachytherapy for Biochemically Recurrent Prostate Cancer following Primary Brachytherapy

    Science.gov (United States)

    Lacy, John M.; Wilson, William A.; Bole, Raevti; Chen, Li; Meigooni, Ali S.; Rowland, Randall G.; Clair, William H. St.

    2016-01-01

    Purpose. In this study, we evaluated our experience with salvage brachytherapy after discovery of biochemical recurrence after a prior brachytherapy procedure. Methods and Materials. From 2001 through 2012 twenty-one patients treated by brachytherapy within University of Kentucky or from outside centers developed biochemical failure and had no evidence of metastases. Computed tomography (CT) scans were evaluated; patients who had an underseeded portion of their prostate were considered for reimplantation. Results. The majority of the patients in this study (61.9%) were low risk and median presalvage PSA was 3.49 (range 17.41–1.68). Mean follow-up was 61 months. At last follow-up after reseeding, 11/21 (52.4%) were free of biochemical recurrence. There was a trend towards decreased freedom from biochemical recurrence in low risk patients (p = 0.12). International Prostate Symptom Scores (IPSS) increased at 3-month follow-up visits but decreased and were equivalent to baseline scores at 18 months. Conclusions. Salvage brachytherapy after primary brachytherapy is possible; however, in our experience the side-effect profile after the second brachytherapy procedure was higher than after the first brachytherapy procedure. In this cohort of patients we demonstrate that approximately 50% oncologic control, low risk patients appear to have better outcomes than others. PMID:27092279

  20. Postal auditing methodology used to find out the performance of high rate brachytherapy equipment

    International Nuclear Information System (INIS)

    This work describes results from a methodology implemented at the Secondary Laboratory for Dosimetric Calibration at CPHR used to check the brachytherapy performance at high doses rate using Cesium 137 or cobalt 60 sources

  1. Sealed source and device design safety testing: Technical report on the findings of task 4 -- Investigation of failed Nitinol brachytherapy wire. Volume 2

    Energy Technology Data Exchange (ETDEWEB)

    Benac, D.J.; Burghard, H.C. [Southwest Research Inst., San Antonio, TX (United States)

    1996-03-01

    This report covers an investigation of the nature and cause of failure in Nitinol brachytherapy sourcewires. The investigation was initiated after two clinical incidents in which sourcewires failed during or immediately after a treatment. The investigation determined that the two clinical Nitinol sourcewires failed in a brittle manner, which is atypical for Nitinol. There were no material anomalies or subcritical flaws to explain the brittle failures. The bend tests also demonstrated that neither moist environment, radiation, nor low-temperature structural transformation was a likely root cause of the failures. However, degradation of the PTFE was consistently evident, and those sourcewires shipped or stored with PTFE sleeves consistently failed in laboratory bend tests. On the basis of the results of this study, it was concluded that the root cause of the in-service failures of the sourcewires was environmentally induced embrittlement due to the breakdown of the PTFE protective sleeves in the presence of the high-radiation field and subsequent reaction or interaction of the breakdown products with the Nitinol alloy.

  2. Sealed source and device design safety testing: Technical report on the findings of task 4 -- Investigation of failed Nitinol brachytherapy wire. Volume 2

    International Nuclear Information System (INIS)

    This report covers an investigation of the nature and cause of failure in Nitinol brachytherapy sourcewires. The investigation was initiated after two clinical incidents in which sourcewires failed during or immediately after a treatment. The investigation determined that the two clinical Nitinol sourcewires failed in a brittle manner, which is atypical for Nitinol. There were no material anomalies or subcritical flaws to explain the brittle failures. The bend tests also demonstrated that neither moist environment, radiation, nor low-temperature structural transformation was a likely root cause of the failures. However, degradation of the PTFE was consistently evident, and those sourcewires shipped or stored with PTFE sleeves consistently failed in laboratory bend tests. On the basis of the results of this study, it was concluded that the root cause of the in-service failures of the sourcewires was environmentally induced embrittlement due to the breakdown of the PTFE protective sleeves in the presence of the high-radiation field and subsequent reaction or interaction of the breakdown products with the Nitinol alloy

  3. 106Ruthenium Brachytherapy for Retinoblastoma

    International Nuclear Information System (INIS)

    Purpose: To evaluate the efficacy of 106Ru plaque brachytherapy for the treatment of retinoblastoma. Methods and Materials: We reviewed a retrospective, noncomparative case series of 39 children with retinoblastoma treated with 106Ru plaques at the Jules-Gonin Eye Hospital between October 1992 and July 2006, with 12 months of follow-up. Results: A total of 63 tumors were treated with 106Ru brachytherapy in 41 eyes. The median patient age was 27 months. 106Ru brachytherapy was the first-line treatment for 3 tumors (4.8%), second-line treatment for 13 (20.6%), and salvage treatment for 47 tumors (74.6%) resistant to other treatment modalities. Overall tumor control was achieved in 73% at 1 year. Tumor recurrence at 12 months was observed in 2 (12.5%) of 16 tumors for which 106Ru brachytherapy was used as the first- or second-line treatment and in 15 (31.9%) of 47 tumors for which 106Ru brachytherapy was used as salvage treatment. Eye retention was achieved in 76% of cases (31 of 41 eyes). Univariate and multivariate analyses revealed no statistically significant risk factors for tumor recurrence. Radiation complications included retinal detachment in 7 (17.1%), proliferative retinopathy in 1 (2.4%), and subcapsular cataract in 4 (9.7%) of 41 eyes. Conclusion: 106Ru brachytherapy is an effective treatment for retinoblastoma, with few secondary complications. Local vitreous seeding can be successfully treated with 106Ru brachytherapy

  4. Validation of GPUMCD for low-energy brachytherapy seed dosimetry

    Energy Technology Data Exchange (ETDEWEB)

    Hissoiny, Sami; Ozell, Benoit; Despres, Philippe; Carrier, Jean-Francois [Ecole polytechnique de Montreal, Departement de genie informatique et genie logiciel, 2500 chemin de Polytechnique, Montreal, QC, H3T 1J4 (Canada); Departement de radio-oncologie, Centre hospitalier universitaire de Quebec (CHUQ), 11 Cote du Palais, Quebec, QC, G1R 2J6 (Canada); Departement de physique, Universite de Montreal, Montreal, QC (Canada) and Departement de radio-oncologie and Centre de recherche du CHUM, Centre hospitalier de l' Universite de Montreal (CHUM), Montreal, QC, H2L 4M1 (Canada)

    2011-07-15

    Purpose: To validate GPUMCD, a new package for fast Monte Carlo dose calculations based on the GPU (graphics processing unit), as a tool for low-energy single seed brachytherapy dosimetry for specific seed models. As the currently accepted method of dose calculation in low-energy brachytherapy computations relies on severe approximations, a Monte Carlo based approach would result in more accurate dose calculations, taking in to consideration the patient anatomy as well as interseed attenuation. The first step is to evaluate the capability of GPUMCD to reproduce low-energy, single source, brachytherapy calculations which could ultimately result in fast and accurate, Monte Carlo based, brachytherapy dose calculations for routine planning. Methods: A mixed geometry engine was integrated to GPUMCD capable of handling parametric as well as voxelized geometries. In order to evaluate GPUMCD for brachytherapy calculations, several dosimetry parameters were computed and compared to values found in the literature. These parameters, defined by the AAPM Task-Group No. 43, are the radial dose function, the 2D anisotropy function, and the dose rate constant. These three parameters were computed for two different brachytherapy sources: the Amersham OncoSeed 6711 and the Imagyn IsoStar IS-12501. Results: GPUMCD was shown to yield dosimetric parameters similar to those found in the literature. It reproduces radial dose functions to within 1.25% for both sources in the 0.5< r <10 cm range. The 2D anisotropy function was found to be within 3% at r = 5 cm and within 4% at r = 1 cm. The dose rate constants obtained were within the range of other values reported in the literature.Conclusion: GPUMCD was shown to be able to reproduce various TG-43 parameters for two different low-energy brachytherapy sources found in the literature. The next step is to test GPUMCD as a fast clinical Monte Carlo brachytherapy dose calculations with multiple seeds and patient geometry, potentially providing

  5. The Activity Check of Brachytherapy Isotope

    International Nuclear Information System (INIS)

    An isotope Ir-192, which is used in brachytherapy depends on import in whole quantities. There are a few ways for its activity. measurement using Welltype chamber or the way to rely on authentic decay table of manufacturer. In-air dosimetry using Farmer Chamber, etc. In this paper, let me introduce the way using Farmer chamber which is easier and simple. With the Farmer chamber and source calibration jig, take a measurement the activity of an isotope Ir-192 and compare the value with the value from decay table of manufacturer and check the activity of source. The result of measurement, compared the value from decay table, by ±2.1. (which belongs to recommendable value for AAPM ±5% as difference of error range). It is possible to use on clinical medicine. With the increase in use of brachytherapy, the increase of import is essential. And an accurate activity check of source is compulsory. For the activity check of source, it was possible to use Farmer chamber and source calibration jig without additional purchase of Well type chamber.

  6. Dose determination in breast tumor in brachytherapy using Iridium-192

    International Nuclear Information System (INIS)

    Thermoluminescent dosimetry studies in vivo and in vitro aiming to determing radiation dose in the breast tumor, in brachytherapy using Iridium-192 was done. The correlation between radiation doses in tumor and external surface of the breast was investigated for correcting the time interval of radiation source implantation. (author)

  7. Multihelix rotating shield brachytherapy for cervical cancer

    International Nuclear Information System (INIS)

    Purpose: To present a novel brachytherapy technique, called multihelix rotating shield brachytherapy (H-RSBT), for the precise angular and linear positioning of a partial shield in a curved applicator. H-RSBT mechanically enables the dose delivery using only linear translational motion of the radiation source/shield combination. The previously proposed approach of serial rotating shield brachytherapy (S-RSBT), in which the partial shield is rotated to several angular positions at each source dwell position [W. Yang et al., “Rotating-shield brachytherapy for cervical cancer,” Phys. Med. Biol. 58, 3931–3941 (2013)], is mechanically challenging to implement in a curved applicator, and H-RSBT is proposed as a feasible solution. Methods: A Henschke-type applicator, designed for an electronic brachytherapy source (Xoft Axxent™) and a 0.5 mm thick tungsten partial shield with 180° or 45° azimuthal emission angles and 116° asymmetric zenith angle, is proposed. The interior wall of the applicator contains six evenly spaced helical keyways that rigidly define the emission direction of the partial radiation shield as a function of depth in the applicator. The shield contains three uniformly distributed protruding keys on its exterior wall and is attached to the source such that it rotates freely, thus longitudinal translational motion of the source is transferred to rotational motion of the shield. S-RSBT and H-RSBT treatment plans with 180° and 45° azimuthal emission angles were generated for five cervical cancer patients with a diverse range of high-risk target volume (HR-CTV) shapes and applicator positions. For each patient, the total number of emission angles was held nearly constant for S-RSBT and H-RSBT by using dwell positions separated by 5 and 1.7 mm, respectively, and emission directions separated by 22.5° and 60°, respectively. Treatment delivery time and tumor coverage (D90 of HR-CTV) were the two metrics used as the basis for evaluation and

  8. Multihelix rotating shield brachytherapy for cervical cancer

    Energy Technology Data Exchange (ETDEWEB)

    Dadkhah, Hossein [Department of Biomedical Engineering, University of Iowa, 1402 Seamans Center for the Engineering Arts and Sciences, Iowa City, Iowa 52242 (United States); Kim, Yusung; Flynn, Ryan T., E-mail: ryan-flynn@uiowa.edu [Department of Radiation Oncology, University of Iowa, 200 Hawkins Drive, Iowa City, Iowa 52242 (United States); Wu, Xiaodong [Department of Radiation Oncology, University of Iowa, 200 Hawkins Drive, Iowa City, Iowa 52242 and Department of Electrical and Computer Engineering, University of Iowa, 4016 Seamans Center for the Engineering Arts and Sciences, Iowa City, Iowa 52242 (United States)

    2015-11-15

    Purpose: To present a novel brachytherapy technique, called multihelix rotating shield brachytherapy (H-RSBT), for the precise angular and linear positioning of a partial shield in a curved applicator. H-RSBT mechanically enables the dose delivery using only linear translational motion of the radiation source/shield combination. The previously proposed approach of serial rotating shield brachytherapy (S-RSBT), in which the partial shield is rotated to several angular positions at each source dwell position [W. Yang et al., “Rotating-shield brachytherapy for cervical cancer,” Phys. Med. Biol. 58, 3931–3941 (2013)], is mechanically challenging to implement in a curved applicator, and H-RSBT is proposed as a feasible solution. Methods: A Henschke-type applicator, designed for an electronic brachytherapy source (Xoft Axxent™) and a 0.5 mm thick tungsten partial shield with 180° or 45° azimuthal emission angles and 116° asymmetric zenith angle, is proposed. The interior wall of the applicator contains six evenly spaced helical keyways that rigidly define the emission direction of the partial radiation shield as a function of depth in the applicator. The shield contains three uniformly distributed protruding keys on its exterior wall and is attached to the source such that it rotates freely, thus longitudinal translational motion of the source is transferred to rotational motion of the shield. S-RSBT and H-RSBT treatment plans with 180° and 45° azimuthal emission angles were generated for five cervical cancer patients with a diverse range of high-risk target volume (HR-CTV) shapes and applicator positions. For each patient, the total number of emission angles was held nearly constant for S-RSBT and H-RSBT by using dwell positions separated by 5 and 1.7 mm, respectively, and emission directions separated by 22.5° and 60°, respectively. Treatment delivery time and tumor coverage (D{sub 90} of HR-CTV) were the two metrics used as the basis for evaluation and

  9. Brachytherapy- past, present and future

    International Nuclear Information System (INIS)

    Discovery of radioactivity by Henry Becquerel and radium by Madame and Pierre Curie was probably the greatest event of 19th century in the field of medical science. Radium was used for brachytherapy as early as 1901. Today almost every organ is amenable to brachytherapy procedure. High dose rate remote afterloading systems have increased the patients comfort and complete radiation protection to the staff during treatment. Computers have not only improved the precision of treatment but also made 3 D conformal brachytherapy possible. As the goal of cancer management is changing from just life preservation to organ and function preservation without compromising cure rate, the role of brachytherapy is becoming more and more prominent. Intensive efforts will be needed to meet with the future challenges. (author). 13 refs

  10. Use of Monte Carlo Methods in brachytherapy; Uso del metodo de Monte Carlo en braquiterapia

    Energy Technology Data Exchange (ETDEWEB)

    Granero Cabanero, D.

    2015-07-01

    The Monte Carlo method has become a fundamental tool for brachytherapy dosimetry mainly because no difficulties associated with experimental dosimetry. In brachytherapy the main handicap of experimental dosimetry is the high dose gradient near the present sources making small uncertainties in the positioning of the detectors lead to large uncertainties in the dose. This presentation will review mainly the procedure for calculating dose distributions around a fountain using the Monte Carlo method showing the difficulties inherent in these calculations. In addition we will briefly review other applications of the method of Monte Carlo in brachytherapy dosimetry, as its use in advanced calculation algorithms, calculating barriers or obtaining dose applicators around. (Author)

  11. Brachytherapy in childhood rhabdomyosarcoma treatment

    International Nuclear Information System (INIS)

    A retrospective study of 21 children with rhabdomyosarcoma treated by brachytherapy to the primary site of the tumor at the Radiotherapy Department of the A.C.Camargo Hospital between january/1980 to june/1993 was undertaken. The main objectives were to comprove the utility of brachytherapy in childhood rhabdomyosarcoma, to evaluate the local control and survival, in association with chemotherapy, to analyze the late effects of the treatment and to determinate the preferential technique to each clinical situation. All patients received brachytherapy to the tumor site. The radioactive isotopes employed were Gold198, Cesium137 and Iridium192. The brachytherapy techniques depended on the tumor site, period of treatment, availability of the radioactive material and stage of the disease. Patients treated exclusively by brachytherapy received 40 Gy to 60 Gy. When brachytherapy was associated with external radiotherapy the dose ranged from 20 Gy to 40 Gy. Local control was achieved in 18 of 20 patients (90%). The global survival and local control survival rates were 61.9% (13/21 patients) and 72,2% (13/18 patients) respectively. (author)

  12. Determination of absorbed dose in water at the reference point D(r{sub 0},{theta}{sub 0}) for an {sup 192}Ir HDR brachytherapy source using a Fricke system

    Energy Technology Data Exchange (ETDEWEB)

    Austerlitz, C.; Mota, H. C.; Sempau, J.; Benhabib, S. M.; Campos, D.; Allison, R.; Almeida, C. E. de; Zhu, D.; Sibata, C. H. [Department of Radiation Oncology, East Carolina University, Greenville, North Carolina 27834 (United States); Institut de Tecniques Energetiques, Universitat Politecnica de Catalunya, 08028 Barcelona (Spain); Department of Radiation Oncology, East Carolina University, Greenville, North Carolina 27834 (United States); Laboratorio de Cie circumflex ncias Radiologicas, Universidade do Estado do Rio de Janeiro, 20550 Rio de Janeiro (Brazil); Department of Radiation Oncology, East Carolina University, Greenville, North Carolina 27834 (United States)

    2008-12-15

    method towards calibration of brachytherapy radiation sources in terms of D(r{sub 0},{theta}{sub 0}) and audit HDR source calibrations.

  13. Local anesthesia for prostate brachytherapy

    International Nuclear Information System (INIS)

    Purpose: To demonstrate the technique and feasibility of prostate brachytherapy performed with local anesthesia only. Methods and Materials: A 5 by 5 cm patch of perineal skin and subcutaneous tissue is anesthetized by local infiltration of 10 cc of 1% lidocaine with epinephrine, using a 25-gauge 5/8-inch needle. Immediately following injection into the subcutaneous tissues, the deeper tissues, including the pelvic floor and prostate apex, are anesthetized by injecting 15 cc lidocaine solution with approximately 8 passes of a 20-gauge 1.0-inch needle. Following subcutaneous and peri-apical lidocaine injections, the patient is brought to the simulator suite and placed in leg stirrups. The transrectal ultrasound (TRUS) probe is positioned to reproduce the planning images and a 3.5- or 6.0-inch, 22-gauge spinal needle is inserted into the peripheral planned needle tracks, monitored by TRUS. When the tips of the needles reach the prostatic base, about 1 cc of lidocaine solution is injected in the intraprostatic track, as the needle is slowly withdrawn, for a total volume of 15 cc. The implants are done with a Mick Applicator, inserting and loading groups of two to four needles, so that a maximum of only about four needles are in the patient at any one time. During the implant procedure, an additional 1 cc of lidocaine solution is injected into one or more needle tracks if the patient experiences substantial discomfort. The total dose of lidocaine is generally limited to 500 mg (50 ml of 1% solution). Results: To date, we have implanted approximately 50 patients in our simulator suite, using local anesthesia. Patients' heart rate and diastolic blood pressure usually showed moderate changes, consistent with some discomfort. The time from first subcutaneous injection and completion of the source insertion ranged from 35 to 90 minutes. Serum lidocaine levels were below or at the low range of therapeutic. There has been only one instance of acute urinary retention in the

  14. Verification of Oncentra brachytherapy planning using independent calculation

    Science.gov (United States)

    Safian, N. A. M.; Abdullah, N. H.; Abdullah, R.; Chiang, C. S.

    2016-03-01

    This study was done to investigate the verification technique of treatment plan quality assurance for brachytherapy. It is aimed to verify the point doses in 192Ir high dose rate (HDR) brachytherapy between Oncentra Masterplan brachytherapy treatment planning system and independent calculation software at a region of rectum, bladder and prescription points for both pair ovoids and full catheter set ups. The Oncentra TPS output text files were automatically loaded into the verification programme that has been developed based on spreadsheets. The output consists of source coordinates, desired calculation point coordinates and the dwell time of a patient plan. The source strength and reference dates were entered into the programme and then dose point calculations were independently performed. The programme shows its results in a comparison of its calculated point doses with the corresponding Oncentra TPS outcome. From the total of 40 clinical cases that consisted of two fractions for 20 patients, the results that were given in term of percentage difference, it shows an agreement between TPS and independent calculation are in the range of 2%. This programme only takes a few minutes to be used is preferably recommended to be implemented as the verification technique in clinical brachytherapy dosimetry.

  15. Fricke gel-layer dosimetry in high dose-rate brachytherapy

    Energy Technology Data Exchange (ETDEWEB)

    Carrara, M. [Medical Physics Unit, Fondazione IRCCS ' Istituto Nazionale Tumori' , Via Venezian 1, I-20133 Milan (Italy); Fallai, C. [Radiotherapy Unit, Fondazione IRCCS ' Istituto Nazionale Tumori' , Via Venezian 1, I-20133 Milan (Italy); Gambarini, G. [Physics Department of the Universita degli Studi and INFN, Sezione di Milano, Via Celoria 16, I-20133 Milan (Italy)], E-mail: grazia.gambarini@mi.infn.it; Negri, A. [Physics Department of the Universita degli Studi and INFN, Sezione di Milano, Via Celoria 16, I-20133 Milan (Italy)

    2010-04-15

    The aim of this study was to evaluate the reliability of Fricke gel-layer dosimeters for the measurement of in-phantom dose distributions produced by a {sup 192}Ir brachytherapy source. The doses obtained were compared to measurements performed with thermoluminescent dosimeters and treatment planning calculations. Fricke gel-layer dosimeters have proven to be a promising tool to measure three-dimensional dose distributions in high dose-rate brachytherapy.

  16. Preparation of 103Pd brachytherapy seeds by electroless plating of 103Pd onto carbon bars

    International Nuclear Information System (INIS)

    A method for preparing 103Pd brachytherapy seeds is reported. The key of the method was to deposit 103Pd onto carbon bars by electroless plating so as to prepare source cores. After each carbon bar with 103Pd was sealed in a titanium capsule, the 103Pd seeds were fabricated. This paper provides valuable experiences and data for the preparation of 103Pd brachytherapy seeds

  17. Study of dose calculation on breast brachytherapy using prism TPS

    International Nuclear Information System (INIS)

    PRISM is one of non-commercial Treatment Planning System (TPS) and is developed at the University of Washington. In Indonesia, many cancer hospitals use expensive commercial TPS. This study aims to investigate Prism TPS which been applied to the dose distribution of brachytherapy by taking into account the effect of source position and inhomogeneities. The results will be applicable for clinical Treatment Planning System. Dose calculation has been implemented for water phantom and CT scan images of breast cancer using point source and line source. This study used point source and line source and divided into two cases. On the first case, Ir-192 seed source is located at the center of treatment volume. On the second case, the source position is gradually changed. The dose calculation of every case performed on a homogeneous and inhomogeneous phantom with dimension 20 × 20 × 20 cm3. The inhomogeneous phantom has inhomogeneities volume 2 × 2 × 2 cm3. The results of dose calculations using PRISM TPS were compared to literature data. From the calculation of PRISM TPS, dose rates show good agreement with Plato TPS and other study as published by Ramdhani. No deviations greater than ±4% for all case. Dose calculation in inhomogeneous and homogenous cases show similar result. This results indicate that Prism TPS is good in dose calculation of brachytherapy but not sensitive for inhomogeneities. Thus, the dose calculation parameters developed in this study were found to be applicable for clinical treatment planning of brachytherapy

  18. Study of dose calculation on breast brachytherapy using prism TPS

    Science.gov (United States)

    Fendriani, Yoza; Haryanto, Freddy

    2015-09-01

    PRISM is one of non-commercial Treatment Planning System (TPS) and is developed at the University of Washington. In Indonesia, many cancer hospitals use expensive commercial TPS. This study aims to investigate Prism TPS which been applied to the dose distribution of brachytherapy by taking into account the effect of source position and inhomogeneities. The results will be applicable for clinical Treatment Planning System. Dose calculation has been implemented for water phantom and CT scan images of breast cancer using point source and line source. This study used point source and line source and divided into two cases. On the first case, Ir-192 seed source is located at the center of treatment volume. On the second case, the source position is gradually changed. The dose calculation of every case performed on a homogeneous and inhomogeneous phantom with dimension 20 × 20 × 20 cm3. The inhomogeneous phantom has inhomogeneities volume 2 × 2 × 2 cm3. The results of dose calculations using PRISM TPS were compared to literature data. From the calculation of PRISM TPS, dose rates show good agreement with Plato TPS and other study as published by Ramdhani. No deviations greater than ±4% for all case. Dose calculation in inhomogeneous and homogenous cases show similar result. This results indicate that Prism TPS is good in dose calculation of brachytherapy but not sensitive for inhomogeneities. Thus, the dose calculation parameters developed in this study were found to be applicable for clinical treatment planning of brachytherapy.

  19. Erectile function after prostate brachytherapy

    International Nuclear Information System (INIS)

    Purpose: To evaluate erectile function after permanent prostate brachytherapy using a validated patient-administered questionnaire and to determine the effect of multiple clinical, treatment, and dosimetric parameters on penile erectile function. Methods and materials: A total of 226 patients with preimplant erectile function determined by the International Index of Erectile Function (IIEF) questionnaire underwent permanent prostate brachytherapy in two prospective randomized trials between February 2001 and January 2003 for clinical Stage T1c-T2c (2002 American Joint Committee on Cancer) prostate cancer. Of the 226 patients, 132 were potent before treatment and, of those, 128 (97%) completed and returned the IIEF questionnaire after brachytherapy. The median follow-up was 29.1 months. Potency was defined as an IIEF score of ≥13. The clinical, treatment, and dosimetric parameters evaluated included patient age; preimplant IIEF score; clinical T stage; pretreatment prostate-specific antigen level; Gleason score; elapsed time after implantation; preimplant nocturnal erections; body mass index; presence of hypertension or diabetes mellitus; tobacco consumption; the volume of the prostate gland receiving 100%, 150%, and 200% of the prescribed dose (V100/150/200); the dose delivered to 90% of the prostate gland (D90); androgen deprivation therapy; supplemental external beam radiotherapy (EBRT); isotope; prostate volume; planning volume; and radiation dose to the proximal penis. Results: The 3-year actuarial rate of potency preservation was 50.5%. For patients who maintained adequate posttreatment erectile function, the preimplant IIEF score was 29, and in patients with brachytherapy-related ED, the preimplant IIEF score was 25. The median time to the onset of ED was 5.4 months. After brachytherapy, the median IIEF score was 20 in potent patients and 3 in impotent patients. On univariate analysis, the preimplant IIEF score, patient age, presence of nocturnal erections

  20. Radiological protection on interstitial brachytherapy and dose determination and exposure rate of an Ir-192 source through the MCNP-4B; Proteccion radiologica en braquiterapia intersticial y determinacion de la dosis y tasa de exposicion de una fuente de Ir-192 mediante el MCNP-4B

    Energy Technology Data Exchange (ETDEWEB)

    Morales L, M.E. [INEN, Av. Angamos Este 2520- Surquillo, Lima (Peru)

    2006-07-01

    The present work was carried out in the Neurological Sciences Institute having as objective to determine the dose and the rate of exhibition of the sources of Iridium 192, Iodine 125 and Palladium 103; which are used to carry out implant in the Interstitial Brachytherapy according to the TG43. For it we carry out a theoretical calculation, its are defined in the enter file: the geometry, materials of the problem and the radiation source, etc; in the MCNP-4B Monte Carlo code, considering a punctual source and for the dose determination we simulate thermoluminescent dosemeters (TLD): at 5 cm, 50 cm, 100 cm and 200 cm of the source. Our purpose is to analyze the radioprotection measures that should take into account in this Institute in which are carried out brain biopsies using a Micro mar stereotactic mark, and in a near future with the collaboration of a doctor and a cuban physique seeks to be carried out the Interstitial Brachytherapy technique with sources of Ir-192 for patient with tumors like glioblastoma, astrocytoma, etc. (Author)

  1. The reference isodose length (RIL) in endovascular brachytherapy: physical aspects

    International Nuclear Information System (INIS)

    Full text: In a forthcoming recommendation of the endovascular GEC ESTRO (European Society for Therapeutic Radiology and Oncology) working group terms and concepts are defined for prescribing, reporting and recording lengths (volumes) for endovascular brachytherapy. Following these recommendation the reference isodose length (RIL) is one of the most important parameter for treatment planning. It is defined as the vessel length at the reference depth (1 or 2 mm) enclosed by the 90 % isodose. The RIL is thus a physical parameter to characterize a source configuration and depends on active source length (ASL), nuclide, source design, and reference depth. RILs are determined by (i) Monte Carlo calculations (EGSnrc code) and (ii) film dosimetry (radiochromic films + special phantom) for three endovascular brachytherapy devices currently in clinical use (192Ir: 23 mm ASL, 32P: 40 mm ASL, 90Sr: 40 mm ASL). The calculated RIL at 2 mm distance from the source axis are 15.4 mm, 36.8 mm and 35.8 mm for the 192Ir, 32P, 90Sr sources, respectively. The results obtained with EGSnrc are in very good agreement with the measured longitudinal dose profiles. The reference isodose length (RIL) is a useful and essential parameter in endovascular brachytherapy treatment planning, which critically depends on source design. Monte Carlo methods are a valuable tool to calculate/verify the RIL of different devices at the respective reference depth. (author)

  2. Experiences with alanine dosimetry in afterloading brachytherapy

    International Nuclear Information System (INIS)

    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

  3. Size Effects of Gold and Iron Nanoparticles on Radiation Dose Enhancement in Brachytherapy and Teletherapy: A Monte Carlo Study

    Directory of Open Access Journals (Sweden)

    Ahad Ollah Ezzati

    2014-08-01

    Full Text Available Introduction In this study, we aimed to calculate dose enhancement factor (DEF for gold (Au and iron (Fe nanoparticles (NPs in brachytherapy and teletherapy, using Monte Carlo (MC method. Materials and Methods In this study, a new algorithm was introduced to calculate dose enhancement by AuNPs and FeNPs for Iridium-192 (Ir-192 brachytherapy and Cobalt-60 (Co-60 teletherapy sources, using the MC method. In this algorithm, the semi-random distribution of NPs was used instead of the regular distribution. Diameters were assumed to be 15, 30, and 100 nm in brachytherapy and 15 and 30 nm in teletherapy. Monte Carlo MCNP4C code was used for simulations, and NP density values were 0.107 mg/ml and 0.112 mg/ml in brachytherapy and teletherapy, respectively. Results AuNPs significantly enhanced the radiation dose in brachytherapy (approximately 60%, and 100 nm diameter NPs showed the most uniform dose distribution. AuNPs had an insignificant effect on teletherapy radiation field, with a dose enhancement ratio of 3% (about the calculation uncertainty or less. In addition, FeNPs had an insignificant effect on both brachytherapy and teletherapy radiation fields. FeNPs dose enhancement was 3% in brachytherapy and 6% (about the calculation uncertainty or less in teletherapy. Conclusion It can be concluded that AuNPs can significantly increase the absorbed dose in brachytherapy; however, FeNPs do not have a noticeable effect on the absorbed dose

  4. SU-E-T-270: Quality Control of Source Strength and Indexer Length in HDR Brachytherapy Using Sun Nuclear Mapcheck2

    International Nuclear Information System (INIS)

    Purpose: The goal of this work was to evaluate Sun Nuclear MapCheck2 capability for quantitative determination of both HDR source strength and position. Predictive power of Mapcheck2 dose matrix, originated by a microSelectron-v2 source from 22mm distance, was investigated. Methods: A Mick MultiDoc phantom with the 1400mm indexer length mark aligned over MapCheck2 central detector plus two additional 5cm plastic slabs were used as a composite phantom. Dose readings were transformed by applying published source anisotropy corrections and experimentally established radial dose and relative sensitivity factors. Angular dependence was not considered. Only readings from diodes located 2cm around the central detector were evaluated. The reproducibility of a fit between transformed dose readings and the ratio of virtual source strength and the square of source-detector distance was investigated. Four parameters were considered in the model: virtual source strength, lateral, longitudinal and vertical source positions. Final source strength calibration factor was calculated from the ratio of reference measurements and results from the fit. Results: Original lateral and longitudinal source position estimations had systematic errors of 0.39mm and 0.75mm. After subtracting these errors, both source positions were predicted with a standard deviation of 0.15mm. Results for vertical positions were reproducible with a standard deviation of 0.05mm. The difference between calculated and reference source strengths from 34 independent measurement setups had a standard deviation of 0.3%. The coefficient of determination for the linear regression between known indexer lengths and results from the fit in the range 1400mm ± 5mm was 0.985. Conclusions: ource strength can be estimated with MapCheck2 at appropriate accuracy levels for quality control. Verification of indexer length with present implementation is more accurate than visual alternatives. Results can be improved by designing a

  5. Salvage brachytherapy for patients with locally persistent nasopharyngeal carcinoma

    International Nuclear Information System (INIS)

    Purpose: Locally persistent nasopharyngeal carcinoma (NPC) carries an increased risk of local failure if additional treatment is not given. This study was conducted to evaluate the outcomes of patients with locally persistent NPC as treated by high-dose-rate (HDR) intracavitary brachytherapy, and to explore whether routine brachytherapy boost could improve the local control. Methods and Materials: Eighty-seven patients with locally persistent NPC treated during 1990-1998 with HDR intracavitary brachytherapy were retrospectively analyzed. Fibreoptic nasopharyngoscopy was performed 3-6 weeks after completion of the primary external radiation therapy (ERT). Biopsies were only taken from suspicious areas. Those with complete regression of local disease were put on observation. Eighty-seven patients were shown to have persistent viable disease at a median time of 6 weeks post-RT. The distribution according to Ho's staging system at initial diagnosis was as follows: Stage I-8, II-33, III-41, IV-5; T1-19, T2-48, T3-20; N0-32, N1-22, N2-28, N3-5. CT scan for restaging was not performed after the documentation of persistent disease. Our policy was to treat all patients with persistent disease with brachytherapy irrespective of the extent of disease just prior to brachytherapy. They were treated with HDR intracavitary brachytherapy, with either cobalt sources or an iridium source, giving 22.5-24 Gy in 3 weekly sessions in all but 4 patients. This dose was prescribed at a distance of 1.5 cm from the center of the surface as defined by the sources in the first six patients and subsequently reduced to 1 cm for the others. Twelve patients were treated with neoadjuvant chemotherapy. To compare the efficacy of brachytherapy, another 383 consecutive nonmetastatic patients, treated with curative intent by ERT, during the years 1990-1993, were evaluated. Multivariate analysis was performed using the Cox regression proportional hazards model. Results: The 5-year actuarial local

  6. Evaluation of resins for use in brachytherapy

    Energy Technology Data Exchange (ETDEWEB)

    Carvalho, Luiz Claudio F.M. Garcia; Ferraz, Wilmar Barbosa; Chrcanovic, Bruno Ramos; Santos, Ana Maria M., E-mail: ferrazw@cdtn.b, E-mail: amms@cdtn.b [Centro de Desenvolvimento da Tecnologia Nuclear (CDTN/CNEN-MG), Belo Horizonte, MG (Brazil)

    2011-07-01

    Brachytherapy is an advanced cancer treatment where radioactive seeds or sources are placed near or directly into the tumor thus reducing the radiation exposure in the surrounding healthy tissues. Prostate cancer can be treated with interstitial brachytherapy in initial stage of the disease in which tiny radioactive seeds with cylindrical geometry are used. Several kinds of seeds have been developed in order to obtain a better dose distribution around them and with a lower cost manufacturing. These seeds consist of an encapsulation, a radionuclide carrier, and X-ray marker. Among the materials that have potential for innovation in the construction of seeds, biocompatible resins appear as an important option. In this paper, we present some characterization results with Fourier transform infrared spectroscopic (FTIR) and ultraviolet-visible spectroscopy (UV-vis) performed on two types of resins in which curing temperatures for each one were varied as also the results of coatings with these resins under titanium substrates. Interactions of these resins in contact with the simulated body fluid were evaluated by atomic force microscopy, scanning electron microscopy, and energy dispersive X-ray spectroscopy. (author)

  7. Application of TSH bioindicator for studying the biological efficiency of neutrons from californium-252 source

    International Nuclear Information System (INIS)

    The effectiveness of neutrons from a Californium-252 source in the induction of various abnormalities in the Tradescantia clone 4430 stamen hair cells (TSH-assay) was studied. The special attention was paid to check whether any enhancement in effects caused by process of boron neutron capture is visible in the cells enriched with boron ions. Two chemicals (borax and BSH) were applied to introduce boron-10 ions into cells. Inflorescence, normal or pretreated with chemicals containing boron, were irradiated in the air with neutrons from a Cf-252 source at KAERI, Taejon, Korea. To estimate the relative biological effectiveness (RBE) in the induction of gene mutations of the neutron beam under the study, Tradescantia inflorescences, without any chemical pretreatment, were irradiated with various doses of X-rays. The ranges of radiation doses used were 0-0.1 Gy in neutrons and 0-0.5 Gy in X-rays. After the time needed to complete the postirradiation repair Tradescantia cuttings were transferred to Cracow, where screening of gene and lethal; mutations, cell cycle alterations in somatic cells have been done, and dose response relationships were figured. The maximal RBE values were estimated in the range of 4.6-6.8. Alterations of RBE value were observed; from 6.8 to 7.8 in the case of plants pretreated with 240 ppm of B-10 from borax, and 4.6 to 6.1 in the case of 400 ppm of B-10 from BSH. Results showed a slight, although statistically insignificant increase in biological efficacy of radiation from the Cf-252 source in samples pretreated with boron containing chemicals. (author)

  8. Computer analysis of nuclear track emulsion exposed to thermal neutrons and Cf source

    Science.gov (United States)

    Mamatkulov, K. Z.; Ambřozová, I.; Artemenkov, D. A.; Bradnova, V.; Kamanin, D. V.; Kattabekov, R. R.; Majling, L.; Marey, A.; Ploc, O.; Rusakova, V. V.; Stanoeva, R.; Turek, K.; Zaitsev, A. A.; Zarubin, P. I.; Zarubina, I. G.

    2016-02-01

    Application of the nuclear track emulsion technique (NTE) in radioactivity and nuclear fission studies is discussed. It is suggested to use a HSP-1000 automated microscope for searching for a collinear cluster tri-partition of heavy nuclei implanted in NTE. Calibrations of α-particles and ion ranges in a novel NTE are carried out. Surface exposures of NTE samples to a Cf-252 source started. Planar events containing fragments and long-range α-particles as well as fragment triples only are studied. Splittings induced by thermal neutrons are studied in boron-enriched emulsion. Use of the image recognition program ”ImageJ” for obtaining characteristics of individual events and for events from the large scan area is presented.

  9. Brachytherapy dosimeter with silicon photomultipliers

    Energy Technology Data Exchange (ETDEWEB)

    Moutinho, L.M., E-mail: moutinho@ua.pt [i3N, Physics Department, University of Aveiro (Portugal); Castro, I.F.C. [i3N, Physics Department, University of Aveiro (Portugal); Peralta, L. [Faculdade de Ciências da Universidade de Lisboa (Portugal); Laboratório de Instrumentação e Física Experimental de Partículas (LIP), Lisboa (Portugal); Abreu, M.C. [Laboratório de Instrumentação e Física Experimental de Partículas (LIP), Lisboa (Portugal); Veloso, J.F.C.A. [i3N, Physics Department, University of Aveiro (Portugal)

    2015-07-01

    In-vivo and in-situ measurement of the radiation dose administered during brachytherapy faces several technical challenges, requiring a very compact, tissue-equivalent, linear and highly sensitive dosimeter, particularly in low-dose rate brachytherapy procedures, which use radioactive seeds with low energy and low dose deposition rate. In this work we present a scintillating optical fiber dosimeter composed of a flexible sensitive probe and a dedicated electronic readout system based on silicon photomultiplier photodetection, capable of operating both in pulse and current modes. The performance of the scintillating fiber optic dosimeter was evaluated in low energy regimes, using an X-ray tube operating at voltages of 40–50 kV and currents below 1 mA, to assess minimum dose response of the scintillating fiber. The dosimeter shows a linear response with dose and is capable of detecting mGy dose variations like an ionization chamber. Besides fulfilling all the requirements for a dosimeter in brachytherapy, the high sensitivity of this device makes it a suitable candidate for application in low-dose rate brachytherapy. According to Peralta and Rego [1], the BCF-10 and BCF-60 scintillating optical fibers used in dosimetry exhibit high variations in their sensitivity for photon beams in the 25–100 kVp energy range. Energy linearity for energies below 50 keV needs to be further investigated, using monochromatic X-ray photons.

  10. Brachytherapy dosimeter with silicon photomultipliers

    Science.gov (United States)

    Moutinho, L. M.; Castro, I. F. C.; Peralta, L.; Abreu, M. C.; Veloso, J. F. C. A.

    2015-07-01

    In-vivo and in-situ measurement of the radiation dose administered during brachytherapy faces several technical challenges, requiring a very compact, tissue-equivalent, linear and highly sensitive dosimeter, particularly in low-dose rate brachytherapy procedures, which use radioactive seeds with low energy and low dose deposition rate. In this work we present a scintillating optical fiber dosimeter composed of a flexible sensitive probe and a dedicated electronic readout system based on silicon photomultiplier photodetection, capable of operating both in pulse and current modes. The performance of the scintillating fiber optic dosimeter was evaluated in low energy regimes, using an X-ray tube operating at voltages of 40-50 kV and currents below 1 mA, to assess minimum dose response of the scintillating fiber. The dosimeter shows a linear response with dose and is capable of detecting mGy dose variations like an ionization chamber. Besides fulfilling all the requirements for a dosimeter in brachytherapy, the high sensitivity of this device makes it a suitable candidate for application in low-dose rate brachytherapy. According to Peralta and Rego [1], the BCF-10 and BCF-60 scintillating optical fibers used in dosimetry exhibit high variations in their sensitivity for photon beams in the 25-100 kVp energy range. Energy linearity for energies below 50 keV needs to be further investigated, using monochromatic X-ray photons.

  11. In vivo dosimetry in brachytherapy

    DEFF Research Database (Denmark)

    Tanderup, Kari; Beddar, Sam; Andersen, Claus Erik; Kertzscher Schwencke, Gustavo Adolfo Vladimir; Cygler, Joanna E.

    2013-01-01

    In vivo dosimetry (IVD) has been used in brachytherapy (BT) for decades with a number of different detectors and measurement technologies. However, IVD in BT has been subject to certain difficulties and complexities, in particular due to challenges of the high-gradient BT dose distribution and the...

  12. Brachytherapy in coronary artery disease

    Energy Technology Data Exchange (ETDEWEB)

    Song, Ho Chun [Chonnam National University Medicine School, Gwangju (Korea, Republic of)

    2006-04-15

    Coronary artery disease is a leading cause of morbidity and mortality across the world. Percutaneous coronary intervention has become the major technique of revascularization. However, restenosis remains a major limitation of this procedure. Recently the need for repeat intervention due to restenosis, the most vexing long-term failure of percutaneous coronary intervention, has been significantly reduced owing to the introduction to two major advances, intracoronary brachytherapy and the drug-eluting stents, intracoronary brachytherapy has been employed in recent years to prevent restenosis lesions with effective results, principally in in-stent restenosis. Restenosis is generally considered as an excessive form of normal wound healing divided up in processes: elastic recoil, neointimal hyperplasia, and negative vascular remodeling. Restenosis has previously been regarded as a proliferative process in which neointimal thickening, mediated by a cascade of inflammatory mediators and other factors, is the key factor. Ionizing radiation has been shown to decrease the proliferative response to injury in animal models of restenosis. Subsequently, several randomized, double-blind trials have demonstrated that intracoronary brachytherapy can reduce the rates to both angiographic restenosis and clinical event rates in patients undergoing percutaneous coronary intervention for in-stent restenosis. Some problems, such as late thrombosis and edge restenosis, have been identified as limiting factors of this technique. Brachytherapy is a promising method of preventing and treating coronary artery restenosis.

  13. Inverse planning and class solutions for brachytherapy treatment planning

    International Nuclear Information System (INIS)

    Brachytherapy or interventional radiooncology is a method of radiation therapy. It is a method, where a small encapsulated radioactive source is placed near to / in the tumour and therefore delivers high doses directly to the target volume. Organs at risk (OARs) are spared due to the inverse square dose fall-off. In the past years there was a slight stagnation in the development of techniques for brachytherapy treatment. While external beam radiotherapy became more and more sophisticated, in brachytherapy traditional methods have been still used. Recently, 3D imaging was considered also as the modality for brachytherapy and more precise brachytherapy could expand. Nowadays, an image guided brachytherapy is state-of-art in many centres. Integration of imaging methods lead to the dose distribution individually tailored for each patient. Treatment plan optimization is mostly performed manually as an adaptation of a standard loading pattern. Recently, inverse planning approaches have been introduced into brachytherapy. The aim of this doctoral thesis was to analyze inverse planning and to develop concepts how to integrate inverse planning into cervical cancer brachytherapy. First part of the thesis analyzes the Hybrid Inverse treatment Planning and Optimization (HIPO) algorithm and proposes a workflow how to safely work with this algorithm. The problem of inverse planning generally is that only the dose and volume parameters are taken into account and spatial dose distribution is neglected. This fact can lead to unwanted high dose regions in a normal tissue. A unique implementation of HIPO into the treatment planning system using additional features enabled to create treatment plans similar to the plans resulting from manual optimization and to shape the high dose regions inside the CTV. In the second part the HIPO algorithm is compared to the Inverse Planning Simulated Annealing (IPSA) algorithm. IPSA is implemented into the commercial treatment planning system. It

  14. Manual on brachytherapy. Incorporating: Applications guide, procedures guide, basics guide

    International Nuclear Information System (INIS)

    This publication is part of practical radiation safety manual series for different fields of application aimed primarily at persons handling radiation sources on a daily routine basis, which could at same time be used by the competent authorities, supporting their efforts in the radiation protection training of workers or medical assistance personnel or helping on-site management to set up local radiation protection rules. It is dedicated to brachytherapy: its application and procedures guides

  15. Results of stereotactic brachytherapy used in the initial management of patients with glioblastoma

    International Nuclear Information System (INIS)

    Recent studies have shown a survival benefit for patients with recurrent glioblastomas treated with stereotactic brachytherapy. On the basis of these encouraging results, we began a prospective study in 1987 to evaluate the use of brachytherapy in patients with newly diagnosed glioblastoma. Patients were considered eligible for this study if they met the following criteria: Karnofsky performance status 70% or greater; tumor size not greater than 5 cm in any dimension; a radiographically well delineated, supratentorial lesion not involving the ependymal surfaces; and pathologically confirmed glioblastoma. We treated 35 such patients between 1987 and 1990 with stereotactic brachytherapy as part of their initial therapy. The treatment protocol involved surgery, partial brain external-beam radiotherapy, and stereotactic brachytherapy with temporary high-activity iodine 125 sources giving an additional 50 Gy to the tumor bed. Chemotherapy was not used in the initial management of these 35 patients. To compare our results with those obtained in a matched control group, we identified 40 patients with glioblastoma treated with surgery and external radiotherapy, with or without chemotherapy, between 1977 and 1986 at our institution. These patients had clinical and radiographic characteristics that would have made them eligible for the brachytherapy protocol. Survival rates at 1 and 2 years after diagnosis were 87% and 57%, respectively, for patients receiving brachytherapy versus 40% and 12.5%, respectively, for the controls (P less than .001). We conclude that stereotactic brachytherapy improves the survival of patients with glioblastoma when it can be incorporated into the initial treatment approach. Unfortunately, only about one in four patients with glioblastoma are suitable candidates for brachytherapy at the time of initial presentation

  16. Demonstration of brachytherapy boost dose-response relationships in glioblastoma multiforme

    International Nuclear Information System (INIS)

    Purpose: To evaluate brachytherapy dose-response relationships in adults with glioblastoma undergoing temporary 125I implant boost after external beam radiotherapy. Methods and Materials: Since June 1987, orthogonal radiographs using a fiducial marker box have been used to verify brain implant source positions and generate dose-volume histograms at the University of California, San Francisco. For adults who underwent brachytherapy boost for glioblastoma from June 1987 through December 1992, tumor volumes were reoutlined to ensure consistency and dose-volume histograms were recalculated. Univariate and multivariate analyses of various patient and treatment parameters were performed evaluating for influence of dose on freedom from local failure (FFLF) and actuarial survival. Results: Of 102 implant boosts, 5 were excluded because computer plans were unavailable. For the remaining 97 patients, analyses with adjustment for known prognostic factors (age, KPS, extent of initial surgical resection) and prognostic factors identified on univariate testing (adjuvant chemotherapy) showed that higher minimum brachytherapy tumor dose was strongly associated with improved FFLF (p = 0.001). A quadratic relationship was found between total biological effective dose and survival, with a trend toward optimal survival probability at 47 Gy minimum brachytherapy tumor dose (corresponding to about 65 Gy to 95% of the tumor volume); survival decreased with lower or higher doses. Two patients expired and one requires hospice care because of brain necrosis after brachytherapy doses > 63 Gy to 95% of the tumor volume with 60 Gy to > 18 cm3 of normal brain. Conclusion: Although higher minimum brachytherapy tumor dose was strongly associated with better local control, a brachytherapy boost dose > 50-60 Gy may result in life-threatening necrosis. We recommend careful conformation of the prescription isodose line to the contrast enhancing tumor volume, delivery of a minimum brachytherapy boost

  17. Intraluminal brachytherapy after metallic stent placement in primary bile duct carcinoma

    International Nuclear Information System (INIS)

    To determine the effect of intraluminal brachytherapy on stent patency and survival after metallic stent placement in patients with primary bile duct carcinoma. Twenty-seven patients with primary bile duct carcinoma underwent metallic stent placement; in 16 of the 27 intraluminal brachytherapy with an iridium-192 source (dose, 25 Gy) was the performed. Obstuction was due to either hilar (n=14) or non-hilar involvement (n=13). For statistical comparison of patients who underwent/did not undergo intraluminal brachytherapy, stent patency and survival were calculated using the Kaplan-Meier method and an independent t test. The mean durations of stent patency and survival were 9.1 and 10.0 months respectively in patients who underwent intraluminal brachytherapy, and 4.2 and 5.0 months in those who did not undergo this procedure (ρ<0.05). The mean durations of stent patency and survival among the 22 patients who died were 7.6 (range, 0.8-16.1) and 8.3 (range, 0.8-17.3) months, respectively, in the eleven patients who underwent intraluminal brachytherapy, and 4.2 (range, 0.9-8.0) and 5.0 (range, 0.9-8.4) months in those whom the procedure was not performed (ρ<0.05). Intraluminal brachytherapy after stent placement extended both stent patency and survival in patients with primary bile duct carcinoma

  18. X-Rays Emitted in Coincidence with the Fission Of Cf252

    International Nuclear Information System (INIS)

    A possible technique for studying charge distribution in fission is the simultaneous measurement of the kinetic energies of both fragments and the energy of the K-X-rays emitted in coincidence with fission. The two kinetic energies define the masses of the fragments and the X-ray energy defines the atomic number of one fragment. For such a measurement to yield information on charge distribution, it is necessary that the number of vacancies in the K-shell vary slowly with the mass and charge of the fragments. If the vacancies are produced in the fission act itself, it seems likely that this condition is satisfied. X-rays so produced would be emitted within ∼ 10-15 s after fission, If, on the other hand, the vacancies are produced by internal conversion of gamma rays emitted after fission, it is quite possible that the yield of X-rays may vary markedly from one nucleus to the next. Such X-rays would be emitted with lifetimes characteristic of the converted gamma rays - probably at least as long as 10-12 s. We have measured the lifetime of the X-rays emitted in coincidence with fission with a time resolution of ∼ 1 ns. The spectrum of X-rays shows two peaks, one at the proper energy for light fission fragments, the other at the proper energy for heavy fragments. The number of K-X-rays per fission is approximately 0,6. The two peaks fall off in approximately the same manner with increasing time after fission. The apparent mean lifetime is about 1 ns, but the decay curve is complex and does not contain any obvious single component. There is no evidence of an appreciable number of K-X-rays emitted with lifetimes less than about 0.4 ns. Our conclusions from these results are that most, if not all, of the K-vacancies are due to internal conversion but that many different gamma-ray lifetimes appear in the decay curve. Experiments are in progress to measure simultaneously the kinetic energies of the two fragments and the K-X-ray energy. (author)

  19. Five-Dimensional Fission-Barrier Calulations from Se-70 to Cf-252

    OpenAIRE

    Moller, Peter; Sierk, Arnold J.; Iwamoto, Akira

    2004-01-01

    We present fission-barrier-height calculations for nuclei throught the Periodic Table based on a realistic macroscopic-microscopic model. Compared to other calculations: (1) we use a deformation space of sufficiently high dimension, sampled densely enough to describe the relevant topography of the fission potential, (2) we unambiguously find the physically relevant saddle points in this space, and (3) we formulate our model so that we obtain continuity of the potential energy at the division ...

  20. Neutron sources and its dosimetric characteristics

    International Nuclear Information System (INIS)

    By means of Monte Carlo methods the spectra of the produced neutrons 252 Cf, 252 Cf/D2O, 241 Am Be, 239 Pu Be, 140 La Be, 239 Pu18O2 and 226 Ra Be have been calculated. With the information of the spectrum it was calculated the average energy of the neutrons of each source. By means of the fluence coefficients to dose it was determined, for each one of the studied sources, the fluence factors to dose. The calculated doses were H, H*(10), Hp,sIab (10, 00), EAP and EISO. During the phase of the calculations the sources were modeled as punctual and their characteristics were determined to 100 cm in the hole. Also, for the case of the sources of 239 Pu Be and 241 Am Be, were carried out calculations modeling the sources with their respective characteristics and the dosimetric properties were determined in a space full with air. The results of this last phase of the calculations were compared with the experimental results obtained for both sources. (Author)

  1. Inverse planning in brachytherapy from radium to high rate 192 iridium afterloading

    International Nuclear Information System (INIS)

    We consider the inverse planning problem in brachytherapy, i.e. the problem to determine an optimal number of catheters, number of sources for low-dose rate brachytherapy (LDR) and the optimal dwell times for high-dose rate brachytherapy (HDR) necessary to obtain an optimal as possible dose distribution. Starting from the 1930s, inverse planning for LDR brachytherapy used geometrically derived rules to determine the optimal placement of sources in order to achieve a uniform dose distribution of a specific level in planes, spheres and cylinders. Rules and nomograms were derived which still are widely used. With the rapid development of 3D imaging technologies and the rapidly increasing computer power we have now entered the new era of computer-based inverse planning in brachytherapy. The inverse planning is now an optimisation process adapted to the individual geometry of the patient. New inverse planning optimisation algorithms are anatomy-based that consider the real anatomy of the tumour and the organs at risk (OAR). Computer-based inverse planning considers various effects such as stability of solutions for seed misplacements which cannot ever be solved analytically without gross simplifications. In the last few years multiobjective (MO) inverse planning algorithms have been developed which recognise the MO optimisation problem which is inherent in inverse planning in brachytherapy. Previous methods used a trial and error method to obtain a satisfactory solution. MO optimisation replaces this trial and error process by presenting a representative set of dose distributions that can be obtained. With MO optimisation it is possible to obtain information that can be used to obtain the optimum number of catheters, their position and the optimum distribution of dwell times for HDR brachytherapy. For LDR brachytherapy also the stability of solutions due to seed migration can also be improved. A spectrum of alternative solutions is available and the treatment planner

  2. Development and Evaluation of Rhenium-188-labeled Radioactive Stents for Restenosis Therapy and Development of Strategies for Radiolabeling Brachytherapy Sources with Palladium-103 CRADA FINAL REPORT

    Energy Technology Data Exchange (ETDEWEB)

    Knapp, F. F. [ORNL

    1998-06-01

    This project involved collaboration between InnerDyne, Inc., and radiopharmaceutical research programs at ORNL and Brookhaven National Laboratory (BNL) which explored new strategies for the development and animal testing of radioactive rhenium-188-labeled implantable stent sources for the treatment of coronary restenosis after angioplasty and the development of chemical species radiolabeled with the palladium-103 radioisotope for the treatment of cancer. Rhenium-l 88 was made available for these studies from radioactive decay of tungsten-188 produced in the ORNL High Flux Isotope Reactor (HFIR). Stent activation and coating technology was developed and provided by InnerDyne, Inc., and stent radiolabeling technology and animal studies were conducted by InnerDyne staff in conjunction with investigators at BNL. Collaborative studies in animals were supported at sites by InnerDyne, Inc. New chemical methods for attaching the palladium-103 radioisotope to bifunctional chelate technologies were developed by investigators at ORNL.

  3. Development and Evaluation of Rhenium-188-labeled Radioactive Stents for Restenosis Therapy and Development of Strategies for Radiolabeling Brachytherapy Sources with Palladium-103

    International Nuclear Information System (INIS)

    This project involved collaboration between InnerDyne, Inc., and radiopharmaceutical research programs at the Oak Ridge National Laboratory (ORNL) and Brookhaven National Laboratory (BNL) which explored new strategies for the development and animal testing of radioactive rhenium-188-labeled implantable stent sources for the treatment of coronary restenosis after angioplasty and the development of chemical species radiolabeled with the palladium-103 radioisotope for the treatment of cancer. Rhenium-188 was made available for these studies from radioactive decay of tungsten-188 produced in the ORNL High Flux Isotope Reactor (HFIR). Stent activation and coating technology was developed and provided by InnerDyne, Inc., and stent radiolabeling technology and animal studies were conducted by InnerDyne staff in conjunction with investigators at BNL. Collaborative studies in animals were supported at sites by InnerDyne, Inc. New chemical methods for attaching the palladium-103 radioisotope to bifunctional chelate technologies were developed by investigators at ORNL

  4. Human error in remote Afterloading Brachytherapy

    International Nuclear Information System (INIS)

    Remote Afterloading Brachytherapy (RAB) is a medical process used in the treatment of cancer. RAB uses a computer-controlled device to remotely insert and remove radioactive sources close to a target (or tumor) in the body. Some RAB problems affecting the radiation dose to the patient have been reported and attributed to human error. To determine the root cause of human error in the RAB system, a human factors team visited 23 RAB treatment sites in the US. The team observed RAB treatment planning and delivery, interviewed RAB personnel, and performed walk-throughs, during which staff demonstrated the procedures and practices used in performing RAB tasks. Factors leading to human error in the RAB system were identified. The impact of those factors on the performance of RAB was then evaluated and prioritized in terms of safety significance. Finally, the project identified and evaluated alternative approaches for resolving the safety significant problems related to human error

  5. Rectal function following prostate brachytherapy

    International Nuclear Information System (INIS)

    Purpose: Quality of life following therapeutic intervention for carcinoma of the prostate gland has not been well documented. In particular, a paucity of data has been published regarding bowel function following prostate brachytherapy. This study evaluated late bowel function in 209 consecutive prostate brachytherapy patients via a one-time questionnaire administered 16-55 months postimplant. Materials and Methods: Two hundred nineteen consecutive patients underwent permanent prostate brachytherapy from April 1995 through February 1998 using either 125I or 103Pd for clinical T1c-T3a carcinoma of the prostate gland. Of the 219 patients, 7 had expired. Of the remaining 212 patients (median follow-up, 28 months), each patient was mailed a self-administered questionnaire (10 questions) with a prestamped return envelope; 209 (98.6%) surveys were returned. Clinical parameters evaluated for bowel dysfunction included patient age, diabetes, hypertension, history of tobacco consumption, clinical T-stage, elapsed time since implant, and prostate ultrasound volume. Treatment parameters included utilization of neoadjuvant hormonal manipulation, utilization of moderate dose external beam radiation therapy prior to implantation, choice of isotope (125I vs. 103Pd), rectal dose (average, median and maximum doses), total implanted seed strength, values of the minimum dose received by 90% of the prostate gland (D90), and the percent prostate volume receiving 100%, 150%, and 200% of the prescribed minimum peripheral dose (V100, V150 and V200, respectively). Because detailed baseline bowel function was not available for these patients, a cross-sectional survey was performed in which 30 newly diagnosed prostate cancer patients of comparable demographics served as controls. Results: The total rectal function scores for the brachytherapy and control patients were 4.3 and 1.6, respectively, out of a total 27 points (p 103Pd resulted in lower radiation doses to the rectum, the choice of

  6. Harmony search optimization for HDR prostate brachytherapy

    Science.gov (United States)

    Panchal, Aditya

    In high dose-rate (HDR) prostate brachytherapy, multiple catheters are inserted interstitially into the target volume. The process of treating the prostate involves calculating and determining the best dose distribution to the target and organs-at-risk by means of optimizing the time that the radioactive source dwells at specified positions within the catheters. It is the goal of this work to investigate the use of a new optimization algorithm, known as Harmony Search, in order to optimize dwell times for HDR prostate brachytherapy. The new algorithm was tested on 9 different patients and also compared with the genetic algorithm. Simulations were performed to determine the optimal value of the Harmony Search parameters. Finally, multithreading of the simulation was examined to determine potential benefits. First, a simulation environment was created using the Python programming language and the wxPython graphical interface toolkit, which was necessary to run repeated optimizations. DICOM RT data from Varian BrachyVision was parsed and used to obtain patient anatomy and HDR catheter information. Once the structures were indexed, the volume of each structure was determined and compared to the original volume calculated in BrachyVision for validation. Dose was calculated using the AAPM TG-43 point source model of the GammaMed 192Ir HDR source and was validated against Varian BrachyVision. A DVH-based objective function was created and used for the optimization simulation. Harmony Search and the genetic algorithm were implemented as optimization algorithms for the simulation and were compared against each other. The optimal values for Harmony Search parameters (Harmony Memory Size [HMS], Harmony Memory Considering Rate [HMCR], and Pitch Adjusting Rate [PAR]) were also determined. Lastly, the simulation was modified to use multiple threads of execution in order to achieve faster computational times. Experimental results show that the volume calculation that was

  7. Paddle-based rotating-shield brachytherapy

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Yunlong; Xu, Weiyu [Department of Electrical and Computer Engineering, University of Iowa, 4016 Seamans Center, Iowa City, Iowa 52242 (United States); Flynn, Ryan T.; Kim, Yusung; Bhatia, Sudershan K.; Buatti, John M. [Department of Radiation Oncology, University of Iowa, 200 Hawkins Drive, Iowa City, Iowa 52242 (United States); Dadkhah, Hossein [Department of Biomedical Engineering, University of Iowa, 1402 Seamans Center, Iowa City, Iowa 52242 (United States); Wu, Xiaodong, E-mail: xiaodong-wu@uiowa.edu [Department of Electrical and Computer Engineering, University of Iowa, 4016 Seamans Center, Iowa City, Iowa 52242 and Department of Radiation Oncology, University of Iowa, 200 Hawkins Drive, Iowa City, Iowa 52242 (United States)

    2015-10-15

    Purpose: The authors present a novel paddle-based rotating-shield brachytherapy (P-RSBT) method, whose radiation-attenuating shields are formed with a multileaf collimator (MLC), consisting of retractable paddles, to achieve intensity modulation in high-dose-rate brachytherapy. Methods: Five cervical cancer patients using an intrauterine tandem applicator were considered to assess the potential benefit of the P-RSBT method. The P-RSBT source used was a 50 kV electronic brachytherapy source (Xoft Axxent™). The paddles can be retracted independently to form multiple emission windows around the source for radiation delivery. The MLC was assumed to be rotatable. P-RSBT treatment plans were generated using the asymmetric dose–volume optimization with smoothness control method [Liu et al., Med. Phys. 41(11), 111709 (11pp.) (2014)] with a delivery time constraint, different paddle sizes, and different rotation strides. The number of treatment fractions (fx) was assumed to be five. As brachytherapy is delivered as a boost for cervical cancer, the dose distribution for each case includes the dose from external beam radiotherapy as well, which is 45 Gy in 25 fx. The high-risk clinical target volume (HR-CTV) doses were escalated until the minimum dose to the hottest 2 cm{sup 3} (D{sub 2cm{sup 3}}) of either the rectum, sigmoid colon, or bladder reached their tolerance doses of 75, 75, and 90 Gy{sub 3}, respectively, expressed as equivalent doses in 2 Gy fractions (EQD2 with α/β = 3 Gy). Results: P-RSBT outperformed the two other RSBT delivery techniques, single-shield RSBT (S-RSBT) and dynamic-shield RSBT (D-RSBT), with a properly selected paddle size. If the paddle size was angled at 60°, the average D{sub 90} increases for the delivery plans by P-RSBT on the five cases, compared to S-RSBT, were 2.2, 8.3, 12.6, 11.9, and 9.1 Gy{sub 10}, respectively, with delivery times of 10, 15, 20, 25, and 30 min/fx. The increases in HR-CTV D{sub 90}, compared to D-RSBT, were 16

  8. Radiation Protection in Brachytherapy. Report of the SEFM Task Group on Brachytherapy; Proteccion radiologica en Braquiterapia. Informe del grupo de trabajo de Braquiterapia de la SEFM

    Energy Technology Data Exchange (ETDEWEB)

    Perez-Calatayud, J.; Corredoira Silva, E.; Crispin Contreras, V.; Eudaldo Puell, T.; Frutos Baraja, J. de; Pino Sorroche, F.; Pujades Claumarchirant, M. C.; Richart Sancho, J.

    2015-07-01

    This document presents the report of the Brachytherapy Task Group of the Spanish Society of Medical Physics. It is dedicated to the radiation protection aspects involved in brachytherapy. The aim of this work is to include the more relevant aspects related to radiation protection issues that appear in clinical practice, and for the current equipment in Spain. Basically this report focuses on the typical contents associated with high dose rate brachytherapy with {sup 1}92Ir and {sup 6}0Co sources, and permanent seed implants with {sup 1}25I, {sup 1}03Pd and {sup 1}31Cs, which are the most current and widespread modalities. Ophthalmic brachytherapy (COMS with {sup 1}25I, {sup 1}06Ru, {sup 9}0Sr) is also included due to its availability in a significant number of spanish hospitals. The purpose of this report is to assist to the medical physicist community in establishing a radiation protection program for brachytherapy procedures, trying to solve some ambiguities in the application of legal requirements and recommendations in clinical practice. (Author)

  9. A quality management program in intravascular brachytherapy.

    Science.gov (United States)

    Chakri, Abderrahim; Thomadsen, Bruce

    2002-12-01

    While simple, intravascular brachytherapy (IVB) presents a considerable potential for harm to the patient. The medical physicist maintains the responsibility to minimize the likelihood of operational problems or dosimetric errors. The principals for safe operation remain the same as with any radiotherapy treatment: to deliver the correct dose, to the correct location, safety. To develop an effective and comprehensive quality management (QM) program for IVB, a physicist should utilize proven risk assessment techniques rather than simply thinking of things to check, and follow guidances such as ISO9001:2000. The proposed QM program includes the following: Procedures designed to assure the safety of the patient. Identification of the patient; tests of the integrity and patency for the delivery catheter, operation of the source train, and patency of the catheter in the treatment position; a check for recovery preparations; and verification of source recovery. Procedures to assure positional accuracy of the treatment: Verification of the positioning the catheter in the artery and of the sources in the catheter. Procedures to assure dosimetry accuracy: Acceptance testing of the device, including verification of the source strength and uniformity, and of the treatment duration tables; verification of the treatment prescription and duration for each patient; and control measures that minimize the likelihood of errors removing the source at the correct time. PMID:12512720

  10. Permanent brachytherapy challenges and solutions : new plastic radioactive seeds and interseed effect correction for online prostate treatment dosimetry

    OpenAIRE

    Abboud, Fadi

    2011-01-01

    The overall subject of this work was the dosimetric study of new, low energy photon sealed sources made of polymer for clinical brachytherapy application. A key goal was to resolve the problem of inaccuracies in real-time dosimetry that occur as a result of self-shielding by seeds (interseed effect), which is neglected by current treatment planning systems (TPS). Permanent brachytherapy implantation has become a popular treatment option in the management of early stage prostate cancer. Adj...

  11. Preparation of a program for the independent verification of the brachytherapy planning systems calculations

    International Nuclear Information System (INIS)

    In this work a program is presented that independently checks for each patient the treatment planning system calculations in low dose rate, high dose rate and pulsed dose rate brachytherapy. The treatment planning system output text files are automatically loaded in this program in order to get the source coordinates, the desired calculation point coordinates and the dwell times when it is the case. The source strength and the reference dates are introduced by the user. The program allows implementing the recommendations about independent verification of the clinical brachytherapy dosimetry in a simple and accurate way, in few minutes. (Author).

  12. Risk analysis of brachytherapy events

    International Nuclear Information System (INIS)

    For prevention radiological events it is necessary to identify hazardous situation and to analyse the nature of committed errors. Though the recommendation on the classification and prevention of radiological events: Radiological accidents has been prepared in the framework of Czech Society of Radiation Oncology, Biology and Physics and it was approved by Czech regulatory body (SONS) in 1999, only a few reports have been submitted up to now from brachytherapy practice. At the radiotherapy departments attention has been paid more likely to the problems of dominant teletherapy treatments. But in the two last decades the usage of brachytherapy methods has gradually increased because .nature of this treatment well as the possibilities of operating facility have been completely changed: new radionuclides of high activity are introduced and sophisticate afterloading systems controlled by computers are used. Consequently also the nature of errors, which can occurred in the clinical practice, has been changing. To determine the potentially hazardous parts of procedure the so-called 'process tree', which follows the flow of entire treatment process, has been created for most frequent type of applications. Marking the location of errors on the process tree indicates where failures occurred and accumulation of marks along branches show weak points in the process. Analysed data provide useful information to prevent medical events in brachytherapy .The results strength the requirements given in Recommendations of SONS and revealed the need for its amendment. They call especially for systematic registration of the events. (authors)

  13. Study of dose calculation on breast brachytherapy using prism TPS

    Energy Technology Data Exchange (ETDEWEB)

    Fendriani, Yoza; Haryanto, Freddy [Nuclear Physics and Biophysics Research Division, FMIPA Institut Teknologi Bandung, Physics Buildings, Jl. Ganesha 10, Bandung 40132 (Indonesia)

    2015-09-30

    PRISM is one of non-commercial Treatment Planning System (TPS) and is developed at the University of Washington. In Indonesia, many cancer hospitals use expensive commercial TPS. This study aims to investigate Prism TPS which been applied to the dose distribution of brachytherapy by taking into account the effect of source position and inhomogeneities. The results will be applicable for clinical Treatment Planning System. Dose calculation has been implemented for water phantom and CT scan images of breast cancer using point source and line source. This study used point source and line source and divided into two cases. On the first case, Ir-192 seed source is located at the center of treatment volume. On the second case, the source position is gradually changed. The dose calculation of every case performed on a homogeneous and inhomogeneous phantom with dimension 20 × 20 × 20 cm{sup 3}. The inhomogeneous phantom has inhomogeneities volume 2 × 2 × 2 cm{sup 3}. The results of dose calculations using PRISM TPS were compared to literature data. From the calculation of PRISM TPS, dose rates show good agreement with Plato TPS and other study as published by Ramdhani. No deviations greater than ±4% for all case. Dose calculation in inhomogeneous and homogenous cases show similar result. This results indicate that Prism TPS is good in dose calculation of brachytherapy but not sensitive for inhomogeneities. Thus, the dose calculation parameters developed in this study were found to be applicable for clinical treatment planning of brachytherapy.

  14. Afterloading: The Technique That Rescued Brachytherapy

    Energy Technology Data Exchange (ETDEWEB)

    Aronowitz, Jesse N., E-mail: jesse.aronowitz@umassmemorial.org

    2015-07-01

    Although brachytherapy had been established as a highly effective modality for the treatment of cancer, its application was threatened by mid-20th century due to appreciation of the radiation hazard to health care workers. This review examines how the introduction of afterloading eliminated exposure and ushered in a brachytherapy renaissance.

  15. High dose rate endovascular brachytherapy in aorto-iliac lesion for the prevention of restenosis

    International Nuclear Information System (INIS)

    This study examined the applicability of endovascular brachytherapy to larger del arteries such as the abdominal aorta and iliac artery. Endovascular brachytherapy using an Ir-192 HDR source was administered 11 times to nine patients who had undergone percutaneous transluminal angioplasty (PTA) between 1995 and 1999. The follow-up lasted 13 to 55 months after treatment (median, 24 months). Eight of the 11 lesions have been controlled so far. Although one case developed thrombus inside the stent five months later, recanalization was achieved by means of retreatment. One patient who underwent low-dose irradiation (6 Gy) without stent implantation showed restenosis five months after treatment. We used a centering catheter that did not block the blood stream for exact centering of the radiation source in larger vessels such as the abdominal aorta. Although endovascular brachytherapy is a promising and safe procedure, careful follow-up is needed to detect untoward reactions such as thrombosis. (author)

  16. High dose rate endovascular brachytherapy in aorto-iliac lesion for the prevention of restenosis

    Energy Technology Data Exchange (ETDEWEB)

    Yamazaki, Hideya [Toyonaka Municipal Hospital, Osaka (Japan); Tomoda, Kaname; Shiomi, Hiroya [Osaka Univ., Suita (Japan). Graduate School of Medicine] [and others

    2002-02-01

    This study examined the applicability of endovascular brachytherapy to larger del arteries such as the abdominal aorta and iliac artery. Endovascular brachytherapy using an Ir-192 HDR source was administered 11 times to nine patients who had undergone percutaneous transluminal angioplasty (PTA) between 1995 and 1999. The follow-up lasted 13 to 55 months after treatment (median, 24 months). Eight of the 11 lesions have been controlled so far. Although one case developed thrombus inside the stent five months later, recanalization was achieved by means of retreatment. One patient who underwent low-dose irradiation (6 Gy) without stent implantation showed restenosis five months after treatment. We used a centering catheter that did not block the blood stream for exact centering of the radiation source in larger vessels such as the abdominal aorta. Although endovascular brachytherapy is a promising and safe procedure, careful follow-up is needed to detect untoward reactions such as thrombosis. (author)

  17. New brachytherapy standards paradigm shift

    International Nuclear Information System (INIS)

    Full text: The absorbed dose rate to water at short distances (1 cm typically) in water, is the quantity of interest for dosimetry in radiotherapy treatments. Moreover, the dose imparted to cancer patients must be known within a narrow band of uncertainty to avoid either damage to the healthy tissue resulting from exceeding international accepted tolerance levels or lack of tumor control due to a low dose delivered to the target volume. The goal for the uncertainty of the dose delivered to the target volume would be around 5% (at the level of one standard deviation), to assure the effectiveness of the radiotherapy treatment. This also takes into account the uncertainties in dose calculation algorithms. In current brachytherapy (BT) treatments, the procedures to determine the absorbed dose imparted to the patient are not based on absorbed dose standards, but are based on measurements traceable to air kerma standards. In fact, the recommended quantity for the calibration of BT gamma ray sources is the reference air kerma rate, KR, defined as the kerma rate to air, in air, at the reference distance of 1 m from the radioactive source, corrected for air attenuation and scattering. The absorbed dose around a BT source is currently calculated by applying the formalism of the international AAPM Task Group 43 protocol and its update. This protocol is based on the air kerma strength, SK, a quantity that is numerically equivalent to KR, at a distance of 1 m from the source. The dose rate constant Λ converts the air-kerma strength SK to the absorbed dose rate to water, D.(r0,θ0), in water at the reference position: D.(r0,θ0) = SK·A (1). Recently, a lower limit of 2,50 % was obtained for the estimated overall uncertainty (at the level of one standard deviation) on measurements of D.(r0,θ0) due to a HDR 192I BT source based on equation (1). However, in most cases the determination of 5K is typically affected by an uncertainty within 0,8 % (at the level of one standard

  18. High dose rate brachytherapy for oral cancer

    International Nuclear Information System (INIS)

    Brachytherapy results in better dose distribution compared with other treatments because of steep dose reduction in the surrounding normal tissues. Excellent local control rates and acceptable side effects have been demonstrated with brachytherapy as a sole treatment modality, a postoperative method, and a method of reirradiation. Low-dose-rate (LDR) brachytherapy has been employed worldwide for its superior outcome. With the advent of technology, high-dose-rate (HDR) brachytherapy has enabled health care providers to avoid radiation exposure. This therapy has been used for treating many types of cancer such as gynecological cancer, breast cancer, and prostate cancer. However, LDR and pulsed-dose-rate interstitial brachytherapies have been mainstays for head and neck cancer. HDR brachytherapy has not become widely used in the radiotherapy community for treating head and neck cancer because of lack of experience and biological concerns. On the other hand, because HDR brachytherapy is less time-consuming, treatment can occasionally be administered on an outpatient basis. For the convenience and safety of patients and medical staff, HDR brachytherapy should be explored. To enhance the role of this therapy in treatment of head and neck lesions, we have reviewed its outcomes with oral cancer, including Phase I/II to Phase III studies, evaluating this technique in terms of safety and efficacy. In particular, our studies have shown that superficial tumors can be treated using a non-invasive mold technique on an outpatient basis without adverse reactions. The next generation of image-guided brachytherapy using HDR has been discussed. In conclusion, although concrete evidence is yet to be produced with a sophisticated study in a reproducible manner, HDR brachytherapy remains an important option for treatment of oral cancer. (author)

  19. Intracavitary mould brachytherapy in malignant tumors of the maxilla

    International Nuclear Information System (INIS)

    Purpose: To integrate brachytherapy in the combined modality management of malignant tumors of the maxilla, as a means of increasing the radiotherapy dose to the tumor bed while avoiding high doses to the orbital contents. Materials and methods: Following a partial or total maxillectomy, a duplication of the interim surgical obturator was created using a wash of vinyl polysiloxane. This mould was used as a carrier for afterloading nylon catheters through which 192-Iridium seed-ribbons were inserted. Following brachytherapy, selected patients also received external beam irradiation. Results and discussion: After a median follow-up of 36 months, 9 out of 11 patients are alive and disease-free; 1 developed a local recurrence and another relapsed at another site in the oral cavity. Transient grade 1 - 2 mucositis at the implant site was observed in all patients. The review of computer isodose distributions showed that the average dose received by the homolateral eyeball was 10% (range 9,2 - 10.0) of the prescribed surface dose to the surgical cavity. Conclusions: Brachytherapy can be integrated in the management of patients with malignant tumors of the maxilla in the form of a custom-made intracavitary mould carrying 192-Iridium sources. We found this technique particularly useful in cases with close or positive surgical margins

  20. Which modality for prostate brachytherapy; Quelle modalite de curietherapie prostatique?

    Energy Technology Data Exchange (ETDEWEB)

    Bossi, A. [Departement de radiotherapie, institut Gustave-Roussy, 94 - Villejuif (France)

    2010-10-15

    Brachytherapy techniques by permanent implant of radioactive sources or by temporary high-dose-rate (HDR) fractions are nowadays extensively used for the treatment of prostatic carcinoma. Long-term results (at 20 years) concerning large amount of patients have been published by major centers confirming both in terms of efficacy and toxicities that permanent implant of radioactive iodine-125 seeds yields at least the same good results of surgery and of external beam irradiation when proposed to patients affected by low-risk disease. For intermediate to high-risk tumors, HDR temporary implants are proposed as a boost for dose escalation. For both techniques, several topics still need to be clarified dealing with a recent enlargement of indications (HDR alone for low-risk, iodine-125 seeds boost for intermediate-high-risk cancers), or with technical aspects (loose seeds versus linked ones, number of fractions and dose for HDR protocols), while dosimetric issues have only recently been addressed by cooperatives groups. Last but not least, there is a real need to address and clearly characterize the correct definition of biochemical disease control both for iodine permanent implant and for HDR implant. New challenges are facing the prostate-brachytherapy community in the near future: local relapse after external beam radiotherapy are currently managed by several salvage treatments (prostatectomy, cryo, high intensity focused ultrasounds [HIFU]) but the role of reirradiation by brachytherapy is also actively investigated. Focal therapy has gained considerable interest in the last 5 years aiming at treating only the area of cancer foci inside the prostate and preserving nearby healthy tissues. Encouraging results have been obtained with the so-called 'minimally invasive' approaches and both permanent seed implantation and HDR brachytherapy techniques may be worthwhile testing in this setting because of their capability of exactly sculpting the dose inside the

  1. Ocular brachytherapy with a holmium-166 irradiator device

    International Nuclear Information System (INIS)

    The ocular brachytherapy is a method that allows controlling ocular tumors. However, the irradiation of the ocular area in high doses can bring damages mainly to the surrounding healthy tissue, such as lens, retina and bone tissue of the orbital area in growth phase. Brachytherapy in comparison to teletherapy allows a large reduction of the absorbed doses in the adjacent tissues avoiding deleterious effects. Various types of radionuclides can be applied to ocular brachytherapy. Those radionuclides shall be encapsulated and placed juxtaposed to the sclera, back to the tumor. Herein, a new device was developed to encapsulate the radioactive material. It can easily place back of the eyeball. A computational model of the ocular area was developed in order to simulate the spatial dose distribution promoted by the holmium-166 nuclide distributed inside the irradiator device. The simulations addressed a device placed on the surface of the sclera, rotated 90 deg taken at the normal axis forward to the lens. The simulation was carried on the code Monte Carlo MCNP5. The computational simulation generates the spatial dose distribution in the treated volume. All continuous beta and the discrete gamma and X-ray spectra emitted by the holmium-166 were incorporated on simulations. The results allow comparing the space dose distribution to other types of sources used for the same end. The sclera absorbed dose, the maximum apical tumor dose, as well as on the tumor base were investigated. Indeed, the tumor thickness defines the conditions of irradiation. The holmium-166 dose distribution provides a tool to propose a better and optimized protocol for ocular brachytherapy. (author)

  2. Strategies and technical aspects in endoluminal HDR brachytherapy

    International Nuclear Information System (INIS)

    Endoluminal brachytherapy is an effective palliative modality to relieve endoluminal obstruction (in bronchus. bile, bile ducts and oesophageal neoplasms) that can be used alone or definitively to boost the primary site after or during a course of external irradiation. It is known that those patients with local complete response after radiotherapy and/or brachytherapy survive longer than those with a worse regional control. So it is really important to deliver the highest dose to the tumour while minimizing side-effects. Our studies are now directed to focus tolerance of bronchial tree vs pulmonary parenchymal tissue of oesophageal mucosa vs pulmonary and gastrointestinal structures of biliary tree vs liver parenchyma. Recent reports relate about mucosal ulceration and stenosis with pseudomembrane build up and/or fatal haemoptysis and haemorrhage. The question that we address now is if it is possible to obtain a real three dimensional view of the isodose curves in patients instead of constantly relying on catheter placements controlling high dose side effects. In our department the operating room is planned for the patient preparation and to enable precise localization of applicators and accurate delivery of HDR brachytherapy. So in the same room anaestesy, endoscopy, X-rays and therapy are performed without the need to transfer patients elsewhere that can lead to catheter displacement. We are also trying to introduce systematically some marker near or in the tumour during endoscopy in order to verify the precise localization of our target in the radiogram. In bronchus HDR-brachytherapy we generally use a specific contrast medium (Hystrast) that allows us to see the entire region of the pulmonary tree where catheters are introduced. So we can conclude that the major improvements achieved because of the integration of application, planning and treatment are 1) Individualization of treatment planning with respect to the target volume. 2) Improvement of planning

  3. Long-Term Results of an RTOG Phase II Trial (00-19) of External-Beam Radiation Therapy Combined With Permanent Source Brachytherapy for Intermediate-Risk Clinically Localized Adenocarcinoma of the Prostate

    International Nuclear Information System (INIS)

    Purpose: External-beam radiation therapy combined with low—doserate permanent brachytherapy are commonly used to treat men with localized prostate cancer. This Phase II trial was performed to document late gastrointestinal or genitourinary toxicity as well as biochemical control for this treatment in a multi-institutional cooperative group setting. This report defines the long-term results of this trial. Methods and Materials: All eligible patients received external-beam radiation (45 Gy in 25 fractions) followed 2–6 weeks later by a permanent iodine 125 implant of 108 Gy. Late toxicity was defined by the Radiation Therapy Oncology Group/European Organization for Research and Treatment of Cancer late radiation morbidity scoring scheme. Biochemical control was defined by the American Society for Therapeutic Radiology and Oncology (ASTRO) Consensus definition and the ASTRO Phoenix definition. Results: One hundred thirty-eight patients were enrolled from 20 institutions, and 131 were eligible. Median follow-up (living patients) was 8.2 years (range, 2.7–9.3 years). The 8-year estimate of late grade >3 genitourinary and/or gastrointestinal toxicity was 15%. The most common grade >3 toxicities were urinary frequency, dysuria, and proctitis. There were two grade 4 toxicities, both bladder necrosis, and no grade 5 toxicities. In addition, 42% of patients complained of grade 3 impotence (no erections) at 8 years. The 8-year estimate of biochemical failure was 18% and 21% by the Phoenix and ASTRO consensus definitions, respectively. Conclusion: Biochemical control for this treatment seems durable with 8 years of follow-up and is similar to high—dose external beam radiation alone or brachytherapy alone. Late toxicity in this multi-institutional trial is higher than reports from similar cohorts of patients treated with high—dose external-beam radiation alone or permanent low—doserate brachytherapy alone, perhaps suggesting further attention to strategies that

  4. The emerging role of high-dose-rate (HDR) brachytherapy as monotherapy for prostate cancer

    International Nuclear Information System (INIS)

    High-dose-rate (HDR) brachytherapy as monotherapy is a comparatively new brachytherapy procedure for prostate cancer. In addition to the intrinsic advantages of brachytherapy, including radiation dose concentration to the tumor and rapid dose fall-off at the surrounding normal tissue, HDR brachytherapy can yield a more homogeneous and conformal dose distribution through image-based decisions for source dwell positions and by optimization of individual source dwell times. Indication can be extended even to T3a/b or a part of T4 tumors because the applicators can be positioned at the extracapsular lesion, into the seminal vesicles, and/or into the bladder, without any risk of source migration or dropping out. Unlike external beam radiotherapy, with HDR brachytherapy inter-/intra-fraction organ motion is not problematic. However, HDR monotherapy requires patients to stay in bed for 1-4 days during hospitalization, even though the actual overall treatment time is short. Recent findings that the α/β value for prostate cancer is less than that for the surrounding late-responding normal tissue has made hypofractionation attractive, and HDR monotherapy can maximize this advantage of hypofractionation. Research on HDR monotherapy is accelerating, with a growing number of publications reporting excellent preliminary clinical results due to the high 'biologically effective dose (BED)' of >200 Gy. Moreover, the findings obtained for HDR monotherapy as an early model of extreme hypofractionation tend to be applied to other radiotherapy techniques such as stereotactic radiotherapy. All these developments point to the emerging role of HDR brachytherapy as monotherapy for prostate cancer. (author)

  5. Relocation of a nucletron microselectron-HDR brachytherapy system

    International Nuclear Information System (INIS)

    Full text: For a period of four weeks, our clinical Nucletron microSelectron high dose rate (HDR) brachytherapy system was pulled out of clinical use and relocated to a new building. During this period decommission tests, de-wiring of the treatment unit and its associated safety system (such as radiation detector, emergency off circuits and door interlocks), transportation of all equipment, re-wiring of this equipment in the new location and recommission tests were carried out. The decommission and recommission test program was designed upon consultation with the manufacturer's (Nucletron) acceptance test procedures and work carried out by others. The ACPSEM tolerances for remote afterloaders was used as a guideline. In addition to mandatory dosimetry, positional, workstation database and safety tests, two Australian Standard compliance tests were carried out. The compliance tests involved one for remote afterloaders and another for treatment room design. This testing program was designed and implemented with the aim of ensuring ongoing safe delivery of brachytherapy doses to the patient. The testing program consisted of two parts. The first involved a series of decommissioning tests that consisted of dosimetry tests such as source and check cable positional accuracy and source calibration tests. In addition to these tests an inventory of standard plans, patient records and system configuration information was catalogued. The second part involved a series of recommission tests and involved carrying out dosimetry tests on the brachytherapy system (positional accuracy and calibration tests), simulating common treatment scenarios (prostate, cervical, vaginal and bile duct) and checking standard plans; patient records and system configuration had remained unchanged. During this period, other tests were carried out. These included Nucletron acceptance and preventative maintenance tests, Australian Standards compliance testing and integrity of network transfer of

  6. Radiological protection of patients in brachytherapy

    International Nuclear Information System (INIS)

    Full text: The prefix 'brachy' means short-range, so brachytherapy is the administration of radiation therapy using small radioactive sources in the form of needles, tubes, wires or seeds, which are placed within the tumor -interstitial form- or very near of it, superficially or in an endo-cavity form. This technique, which was limited by the size of the primary tumor, has the advantage, that the radiation, can be adjusted to the size and shape of the tumor volume and the radioisotope used, - short range -, is selected with the criteria of getting the dose in the organs at risk, as low as possible, making what it is known as conformal radiotherapy. Radioactive sources may be permanent or temporary implants. The application of radioactive material, can be manually or automatically. In the first case, a major breakthrough from the radioprotection point of view, was the use of afterloading devices, methodology highly recommended to reduce the radiation exposure to staff. With the development of technology, remotely controlled afterloading devices were introduced, which in addition to complying with the above requirement, allow the source to move in different positions along catheters housed in one or more channels, making therapeutic brachytherapy treatments in tumor volumes possible, that due to its length, decades ago would have been an unthinkable deal. In all cases, sources, which may vary from the 3 mm in length, 125 Iodine or 198 Gold seeds, to extensive wires of 192 Iridium, are encapsulated for two main purposes: preventing leakage of radioactive material and absorption of unwanted radiation, alpha and beta, produced by the radioactive decay. Consequently, it should be highly unlikely that the radioactive material, could be lost or located in the patient, in a different place of the one that was planned. However, history shows us the opposite. Its is known the kind of deterministic effect that radiation is going to produce in the tumor, where the severity of

  7. The Transition from 2-D Brachytherapy to 3-D High Dose Rate Brachytherapy

    International Nuclear Information System (INIS)

    Brachytherapy is a major treatment modality in the treatment of common cancers including cervical cancer. This publication addresses the recent technological change in brachytherapy treatment planning with better access to 3-D volumetric patient imaging modalities including computed tomography (CT) and magnetic resonance (MR) as opposed to traditional 2-D planar images. In the context of 2-D and 3-D brachytherapy, the publication provides definitions, clinical indications, transitioning milestones, commissioning steps, quality assurance measures, and a related questionnaire. Staff training and resourcing are also addressed. The publication will serve as a guide to radiotherapy departments in Member States who wish to make the transition from 2-D to 3-D brachytherapy

  8. Study and development of methodology for radioactive iodine fixation in polymeric substrate for manufacturing sources used in brachytherapy; Estudo e desenvolvimento de metodologia para fixacao de iodo radioativo em substrato polimerico para confeccao de fontes utilizadas em braquiterapia

    Energy Technology Data Exchange (ETDEWEB)

    Rodrigues, Bruna T.; Souza, Carla D.; Benega, Marcos A.G. and others, E-mail: bteigarodrigues@gmail.com, E-mail: carladdsouza@yahoo.com.br, E-mail: marcosagbenega@gmail.com [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil). Centro de Tecnologia das Radiacoes

    2014-07-01

    According global estimates of Globocan 2012 project of the International Agency for Research of Cancer, of the World Health Organization, there were 14,1 million new cases of cancer and a total of 8,2 million deaths from cancer. Also show that in 2030, the overall load will be 21,4 million new cases and 13,2 million cancer deaths. One of the prostate cancer therapy is brachytherapy, used in early and middle stages of the disease. It is made with the introduction of seeds with radioactive material within the tumor or in nearby regions, affecting the minimum surrounding tissues. The aim of this work is the study and developing the deposition of radioactive iodine on the polymeric substrate method, and an analysis relating the efficiency of the method to implementation in the laboratory of brachytherapy from IPEN. Iodine-125 is adsorbed on an epoxy resin solution. The objective of this study is to offer a new proposal for seeds. The results will give the data for the radiation protection and the procedures for radioactive waste management.

  9. Preliminary experience on the implementation of computed tomography (CT)-based image guided brachytherapy (IGBT) of cervical cancer using high-dose-rate (HDR) Cobalt-60 source in University of Malaya Medical Centre (UMMC)

    Science.gov (United States)

    Jamalludin, Z.; Min, U. N.; Ishak, W. Z. Wan; Malik, R. Abdul

    2016-03-01

    This study presents our preliminary work of the computed tomography (CT) image guided brachytherapy (IGBT) implementation on cervical cancer patients. We developed a protocol in which patients undergo two Magnetic Resonance Imaging (MRI) examinations; a) prior to external beam radiotherapy (EBRT) and b) prior to intra-cavitary brachytherapy for tumour identification and delineation during IGBT planning and dosimetry. For each fraction, patients were simulated using CT simulator and images were transferred to the treatment planning system. The HR-CTV, IR-CTV, bladder and rectum were delineated on CT-based contouring for cervical cancer. Plans were optimised to achieve HR-CTV and IR-CTV dose (D90) of total EQD2 80Gy and 60Gy respectively, while limiting the minimum dose to the most irradiated 2cm3 volume (D2cc) of bladder and rectum to total EQD2 90Gy and 75Gy respectively. Data from seven insertions were analysed by comparing the volume-based with traditional point- based doses. Based on our data, there were differences between volume and point doses of HR- CTV, bladder and rectum organs. As the number of patients having the CT-based IGBT increases from day to day in our centre, it is expected that the treatment and dosimetry accuracy will be improved with the implementation.

  10. Brachytherapy of stage II mobile tongue carcinoma. Prediction of local control and QOL

    International Nuclear Information System (INIS)

    There is no consensus as to the prognostic model for brachytherapy of tongue carcinoma. This study was designed to evaluate the prognostic factors for local control based on a large population under a unified treatment policy. Between 1970 and 1998, 433 patients with stage II tongue squamous cell carcinoma were treated by low-dose-rate brachytherapy. This series included 277 patients treated with a linear source with a minimum follow-up of 3 years. A spacer was introduced in 1987. The primary local control rates were 85.6%. In the multivariate analysis, an invasive growth pattern was a significant factor for local recurrence. The disease-related survival was influenced by old age and an invasive growth pattern. A spacer lowered mandibular bone complications. The growth pattern was the most important factor for recurrence. Brachytherapy was associated with a high cure rate and the use of spacers brought about good quality of life (QOL)

  11. Characteristics of the radiochromic film Gafchromictm EBT3 model for use in brachytherapy

    International Nuclear Information System (INIS)

    Brachytherapy is a radiotherapy treatment modality using radioactive sealed sources within walking distance of the tumor, reducing the risk of applying an unwanted dose to adjacent healthy tissues. For brachytherapy is reliable, it is necessary to establish a dosimetric practices program aimed at determining the optimal dose of radiation for this radiotherapy practice. This paper presents the application of two methodologies for the dosimetry using radiochromic films. Experimental measurements were performed with EBT3 films in phantoms consisting of homogeneous and heterogeneous material (lung, bone and soft tissue) built especially for dose measurements in brachytherapy. The processing and analysis of the resulting images of the experimental procedure were performed with ImageJ software and MATLAB. The results were evaluated from comparisons dose of experimental measurements and simulations obtained by the Monte Carlo method. (author)

  12. CT based HDR brachytherapy for intracavitary applications

    International Nuclear Information System (INIS)

    Brachytherapy is most commonly used in combination with external radiotherapy for gynecological cancers of cervix, vagina and endometrium. The characteristic rapid fall off of the dose in brachytherapy makes it useful to deliver a localized high dose to tumor. In gynecological applications the dose limiting critical structures are bladder and rectum. The dose received by rectum and bladder has been an interesting issue all these decades. This work presents the dosimetric and planning aspects of CT based High Dose Rate brachytherapy for intracavitary applications

  13. Construction of a anthropomorphic phantom for dose measurement in hands in brachytherapy procedures

    International Nuclear Information System (INIS)

    The main objective of this work was to show the differences between the dose value measured by dosimeter endpoint and the values measured in different points inside the hand during brachytherapy procedures. For this, the procedures involved in the handling of sources were analyzed and the simulated using an anthropomorphic phantom hand

  14. Tumor dose enhancement by nanoparticles during high dose rate 192 Ir brachytherapy

    Directory of Open Access Journals (Sweden)

    Mansour Zabihzadeh

    2015-01-01

    Conclusion: Injecting of high-Z gold NPs into tumor increases the absorbed dose of tumor irradiated with 192 Ir HDR brachytherapy source. Size, geometry, concentration, and distribution model of NPs and tumor depth are crucial factors to accurately estimate the DEF.

  15. Verification of dosimetry planning in brachytherapy in format Dicom and EUD calculation of Risk in bodies

    International Nuclear Information System (INIS)

    This work Describes a program that automates the verification of the schedules in brachytherapy (configuration and dosimetric treatment parameters) for sources of Ir-192 (mHDR v2) and Co-60 (Co0.A86) from the plan exported in DICOM format data. (Author)

  16. Acute urinary toxicity following transperineal prostate brachytherapy using a modified Quimby loading method

    International Nuclear Information System (INIS)

    Purpose: To examine the acute urinary toxicity following transperineal prostate implant using a modified Quimby loading method with regard to time course, severity, and factors that may be associated with a higher incidence of morbidity. Methods and Materials: One hundred thirty-nine patients with prostate adenocarcinoma treated with brachytherapy from 1997 through 1999 had follow-up records available for review. Patients considered for definitive brachytherapy alone included those with prostate specific antigen (PSA) ≤6, Gleason score (GS) ≤6, clinical stage 6, PSA>6, or Stage>T2a were treated with external beam radiation therapy followed by brachytherapy boost. Sources were loaded according to a modified Quimby method. At each follow-up, toxicity was graded based on a modified RTOG urinary toxicity scale. Results: Acute urinary toxicity occurred in 88%. Grade I toxicity was reported in 23%, grade II in 45%, and grade III in 20%, with 14% requiring prolonged (greater than 1 week) intermittent or indwelling catheterization. Overall median duration of symptoms was 12 months. There was no difference in duration of symptoms between patients treated with I-125 or Pd-103 sources (p=0.71). After adjusting for GS and PSA, multivariate logistic regression analysis showed higher incidence of grade 3 toxicity in patients with larger prostate volumes (p=0.002), and those with more seeds implanted (p<0.001). Higher incidence of prolonged catheterization was found in patients receiving brachytherapy alone (p=0.01), with larger prostate volumes (p=0.01), and those with more seeds implanted (p<0.001). Conclusion: Interstitial brachytherapy for prostate cancer leads to a high incidence of acute urinary toxicity, most of which is mild to moderate in severity. A prolonged need for catheterization can occur in some patients. Patients receiving brachytherapy alone, those with prostate volumes greater than 30 cc, and those implanted with a greater number of seeds have the highest

  17. Pulsed low dose rate brachytherapy for pelvic malignancies

    International Nuclear Information System (INIS)

    Purpose: The pulsed low dose rate remote afterloading unit was designed to combine the radiation safety and isodose optimization advantages of high dose rate technology with the radiobiologic advantages of continuous low dose rate brachytherapy. This is the first report of a prospective clinical trial evaluating the relative incidence of acute toxicity and local control in patients with pelvic malignancies who underwent interstitial or intracavitary brachytherapy with the pulsed low dose rate remote afterloader. Methods and Materials: From 5/11/92-6/21/95, 65 patients underwent 77 brachytherapy procedures as part of their treatment regimen for pelvic malignancies. Using the pulsed low dose rate Selectron, equipped with a single cable-driven 0.3-1.0 Ci Ir192 source, target volume doses of 0.40-0.85 Gy per pulse were prescribed to deliver the clinically determined dose. Forty-five intracavitary and 32 interstitial procedures were performed. Fifty-four patients had primary and 11 recurrent disease. Patients were followed closely to assess incidence of Grade 3-5 acute and delayed toxicity, local control, and survival. Results: With a median follow-up of 16.1 months (range 1-29), 33 patients are NED, 10 alive with disease, 13 dead with disease, 4 dead of intercurrent disease, and 5 lost to follow-up. Local control was maintained until last follow-up or death in 48 cases, local failure occurred in 11, unknown in 5. Grade 3-5 acute toxicities (requiring medical or surgical intervention) occurred in 5 out of 77 procedures (6.5%), delayed complications in 10 patients (15% actuarial incidence at 2 years). In the 52 procedures performed for 42 patients with cervix cancer, the acute toxicity incidence was 5.8%, with a 14% 2-year actuarial incidence of delayed complications. Of 32 interstitial templates performed on 30 patients for pelvic malignancies, there were three incidences of acute toxicity and five delayed toxicities. Conclusion: Using the parameters described for this

  18. Treatment of soft-tissue sarcomas of children through brachytherapy

    International Nuclear Information System (INIS)

    Twelve children were treated from January 1979 to June 1986 and the age range was three months to 14 years. Ten patients had implanted sources in the tumour tissue and two had a surface radioactive applicator. Eleven children had local control of disease, four with long term survival (longer than 50 months), good cosmetic and functional results and seven with shorter follow-up (minimal 17 months). Only one local relapse occurred in the irradiated area, five months after treatment. Brachytherapy may be an useful modality of treatment in pediatric oncology making possible the reduction of external therapy dose, minimizing the late effects of treatment, with better survival. (author)

  19. AB012. Brachytherapy for localized prostate cancer

    Science.gov (United States)

    Xu, Yong; Yang, Yong

    2016-01-01

    Background To evaluate the security and effect of brachytherapy for localized prostate cancer. Methods Forty five patients with Tl–T2 prostate cancer were treated with real-time transperineal ultrasound-guide 125I seeds prostate implantation. Results The median operation time was 90 min, the median number of I seeds used was 56. The follow up time was 12–48 months, the cases of PSA Brachytherapy for localized prostate cancer is safe and effective.

  20. Dose volume analysis in brachytherapy and stereotactic radiosurgery

    Energy Technology Data Exchange (ETDEWEB)

    Tozer-Loft, S.M

    2000-12-01

    A brief introduction to three branches of radiotherapy is given: interstitial brachytherapy, external beam megavoltage radiotherapy, and stereotactic radiosurgery. The current interest in issues around conformity, uniformity and optimisation is explained in the light of technical developments in these fields. A novel method of displaying dose-volume information, which mathematically suppresses the inverse-square law, as first suggested by L.L. Anderson for use in brachytherapy is explained in detail, and some improvements proposed. These 'natural' histograms are extended to show the effects of real point sources which do not exactly follow the inverse-square law, and to demonstrate the in-target dose-volume distribution, previously unpublished. The histograms are used as a way of mathematically analysing the properties of theoretical mono-energetic radionuclides, and for demonstrating the dosimetric properties of a potential new brachytherapy source (Ytterbium-169). A new modification of the Anderson formalism is then described for producing Anderson Inverse-Square Shifted (AISS) histograms for the Gamma Knife, which are shown to be useful for demonstrating the quality of stereotactic radiosurgery dose distributions. A study is performed analysing the results of Gamma Knife treatments on 44 patients suffering from a benign brain tumour (acoustic neuroma). Follow-up data is used to estimate the volume shrinkage or growth of each tumour, and this measure of outcome is compared with a range of figures of merit which express different aspects of the quality of each dose distributions. The results are analysed in an attempt to answer the question: What are the important features of the dose distribution (conformality, uniformity, etc) which show a definite relationship with the outcome of the treatment? Initial results show positively that, when Gamma Knife radiosurgery is used to treat acoustic neuroma, some measures of conformality seem to have a surprising

  1. Brachytherapy for early oral tongue cancer. Low dose rate to high dose rate

    International Nuclear Information System (INIS)

    To examine the compatibility of low dose rate (LDR) with high dose rate (HDR) brachytherapy, we reviewed 399 patients with early oral tongue cancer (T1-2N0M0) treated solely by brachytherapy at Osaka University Hospital between 1967 and 1999. For patients in the LDR group (n=341), the treatment sources consisted of Ir-192 pin for 227 patients (1973-1996; irradiated dose, 61-85 Gy; median, 70 Gy), Ra-226 needle for 113 patients (1967-1986; 55-93 Gy; median, 70 Gy). Ra-226 and Ir-192 were combined for one patient. Ir-192 HDR (microSelectron-HDR) was used for 58 patients in the HDR group (1991-present; 48-60 Gy; median, 60 Gy). LDR implantations were performed via oral and HDR via a submental/submandibular approach. The dose rates at the reference point for the LDR group were 0.30 to 0.8 Gy/h, and for the HDR group 1.0 to 3.4 Gy/min. The patients in the HDR group received a total dose of 48-60 Gy (8-10 fractions) during one week. Two fractions were administered per day (at least a 6-h interval). The 3- and 5-year local control rates for patients in the LDR group were 85% and 80%, respectively, and those in the HDR group were both 84%. HDR brachytherapy showed the same lymph-node control rate as did LDR brachytherapy (67% at 5 years). HDR brachytherapy achieved the same locoregional result as did LDR brachytherapy. A converting factor of 0.86 is applicable for HDR in the treatment of early oral tongue cancer. (author)

  2. Radiation Protection Training in Intracoronary Brachytherapy

    International Nuclear Information System (INIS)

    To report the educational objectives and contents on Radiation Protection (RP) for the practice of Intracoronary Brachytherapy (ICB) procedures. The wide international experience on training programs for ICB as well as our own experience organizing several courses aimed at Cardiologists, Radio therapists and Medical Physicists has been used to elaborate specific RP objectives and contents. The objectives, differentiated for Cardiologists, Radio therapists, Medical Physicists, Nurses and Technicians, pretend to guarantee the safety and RP of both patient and staff in the procedures of ICB. The objectives are necessarily different because their RP formation and their role in the procedure are different. The general topics included in RP training programmes for ICB could be: general topics on RP (Interaction of radiation and matter, RP principles, radiobiology, etc), principles of operation of ICB and interventional X-ray equipment, quantification of radiation dose and risks, optimisation of protection of staff and patients, accidents and emergencies, regulations, responsibilities, quality assurance program, handling of ICB sources, installation and commissioning. Training programs based on the objectives presented in this paper would encourage positive safety culture in ICB and can also be used as a starting point by the Regulatory Authority for the authorization of new Installations and credentialing of professionals involved in this technique as well as for the continuous education of the staff involved. (Author) 10 refs

  3. Intraluminal brachytherapy in treatment of malignant obstructive jaundice

    International Nuclear Information System (INIS)

    Objective: To study the practicability and preliminary effect of intraluminal brachytherapy in treatment of malignant obstructive jaundice. Methods: Intraluminal brachytherapy was performed in 4 patients who had been treated with biliary stent implantation. Results: No complications related to intraluminal brachytherapy had happened. One patient was followed up by means of CT, showing reduction in tumor size. Conclusion: Intraluminal brachytherapy is a safe and effective method in treating malignant tumor causing obstructive jaundice

  4. Brachytherapy next generation: robotic systems.

    Science.gov (United States)

    Popescu, Tiberiu; Kacsó, Alex Cristian; Pisla, Doina; Kacsó, Gabriel

    2015-12-01

    In a field dominated by external beam radiation therapy (EBRT), both the therapeutic and technical possibilities of brachytherapy (BT) are underrated, shadowed by protons and intensity modulated radiotherapy. Decreasing expertise and indications, as well as increasing lack of specific BT training for radiation therapy (RT) residents led to the real need of shortening its learning curve and making it more popular. Developing robotic BT devices can be a way to mitigate the above issues. There are many teams working at custom-made robotic BT platforms to perfect and overcome the limitations of the existing systems. This paper provides a picture of the current state-of-the-art in robotic assisted BT, as it also conveys the author's solution to the problem, a parallel robot that uses CT-guidance. PMID:26816510

  5. Medical physics aspects of ophthalmic brachytherapy

    International Nuclear Information System (INIS)

    Intraocular melanoma is the most common primary malignancy of the eye. Radiation therapy using ophthalmic plaque has proved successful in the management of various ocular lesions. Although a few centres were using 90Sr/90Y plaques for shallow turtlours some years ago, eye plaque therapy was not a common practice in India. A revived interest in the use of eye plaque therapy and very high cost of imported sources has led to the development and production of 125I seed sources by the Radiopharmaceuticals Division, BARC. This report presents a brief description on the clinical, dosimetry and radiation safety aspects of 90Sr/90Y and 106Ru/106Rh beta ray and 125I gamma ray eye plaque applicators. This report has been divided in five Sections. Section I presents general introduction of ophthalmic brachytherapy including the structure of a human eye, types of ophthalmic plaques and characteristics of radioisotopes commonly used in such applications. A brief review of sources, applicators and dosimetry of 90Sr/90Y and 106Ru/106Rh beta and 125I gamma ophthalmic plaques are given in Section II and Section III, respectively. Section IV contains the single seed dosimetry data of BARC OcuProsta 125I seed as well as dosimetry data of typical eye plaques loaded with BARC OcuProsta 125I seed. Quality assurance and radiation safety aspects of these eye applicators are described in Section V. A proforma of the application required to be filled in by the user institution for obtaining regulatory consent to start eye plaque therapy has also been appended to this report. (author)

  6. Navigation system for interstitial brachytherapy

    International Nuclear Information System (INIS)

    The purpose of the stud was to develop a computed tomography (CT) based electromagnetic navigation system for interstitial brachytherapy. This is especially designed for situations when needles have to be positioned adjacent to or within critical anatomical structures. In such instances interactive 3D visualisation of the needle positions is essential. The material consisted of a Polhemus electromagnetic 3D digitizer, a Pentium 200 MHz laptop and a voice recognition for continuous speech. In addition, we developed an external reference system constructed of Perspex which could be positioned above the tumour region and attached to the patient using a non-invasive fixation method. A specially designed needle holder and patient bed were also developed. Measurements were made on a series of phantoms in order to study the efficacy and accuracy of the navigation system. The mean navigation accuracy of positioning the 20.0 cm length metallic needles within the phantoms was in the range 2.0-4.1 mm with a maximum of 5.4 mm. This is an improvement on the accuracy of a CT-guided technique which was in the range 6.1-11.3 mm with a maximum of 19.4 mm. The mean reconstruction accuracy of the implant geometry was 3.2 mm within a non-ferromagnetic environment. We found that although the needles were metallic this did not have a significant influence. We also found for our experimental setups that the CT table and operation table non-ferromagnetic parts had no significant influence on the navigation accuracy. This navigation system will be a very useful clinical tool for interstitial brachytherapy applications, particularly when critical structures have to be avoided. It also should provide a significant improvement on our existing technique

  7. Deterministic calculations of radiation doses from brachytherapy seeds

    International Nuclear Information System (INIS)

    Brachytherapy is used for treating certain types of cancer by inserting radioactive sources into tumours. CDTN/CNEN is developing brachytherapy seeds to be used mainly in prostate cancer treatment. Dose calculations play a very significant role in the characterization of the developed seeds. The current state-of-the-art of computation dosimetry relies on Monte Carlo methods using, for instance, MCNP codes. However, deterministic calculations have some advantages, as, for example, short computer time to find solutions. This paper presents a software developed to calculate doses in a two-dimensional space surrounding the seed, using a deterministic algorithm. The analysed seeds consist of capsules similar to IMC6711 (OncoSeed), that are commercially available. The exposure rates and absorbed doses are computed using the Sievert integral and the Meisberger third order polynomial, respectively. The software also allows the isodose visualization at the surface plan. The user can choose between four different radionuclides (192Ir, 198Au, 137Cs and 60Co). He also have to enter as input data: the exposure rate constant; the source activity; the active length of the source; the number of segments in which the source will be divided; the total source length; the source diameter; and the actual and effective source thickness. The computed results were benchmarked against results from literature and developed software will be used to support the characterization process of the source that is being developed at CDTN. The software was implemented using Borland Delphi in Windows environment and is an alternative to Monte Carlo based codes. (author)

  8. Biological Shielding Design Effectiveness of the Brachytherapy Unit at the Korle Bu Teaching Hospital in Ghana Using Mcnp5 Monte Carlo Code

    OpenAIRE

    C.C. Arwui; E.O. Darko; P. Deatanyah; S. Wotorchi-Gordon; H. Lawluvi; Kpeglo, D. O.; G. Emi-Reynolds

    2011-01-01

    Design objectives for brachytherapy treatment facilities require sufficient shielding to reduce primary and scatter radiation to design limit in order to limit exposure to patients, staff and the general public. The primary aim of this study is to verify whether shielding of the brachytherapy unit at the Korle Bu teaching Hospital in Ghana provides adequate protection in order to assess any radiological health and safety impact and also test the suitability of other available sources. The stu...

  9. Physics and quality assurance of low dose rate brachytherapy

    International Nuclear Information System (INIS)

    Purpose: The purpose of this course is to review the physical principles underlying design, clinical application and execution of interstitial and intracavitary implants in the classical low dose-rate (LDR) range. This year, the course will focus on quality assurance of sources, applicators and treatment planning software. In addition, development of procedures and QA checks designed optimize treatment delivery accuracy and patient safety during each individual procedure will be reviewed. The level of presentation will be designed to accommodate both physicists and physicians. Implementation of recently published AAPM Task Group reports (no. 40, 'Comprehensive Quality Assurance' and No. 43, 'Dosimetry of Interstitial Brachytherapy Sources') will be reviewed. Outline: (A) General Principles (1) QA endpoints: temporal accuracy, positional accuracy, dose delivery accuracy, and safety of the patient, personnel, and the institution (2) QA procedure development: forms, checklists, test development and design of treatment delivery procedures (B) QA of treatment delivery devices (1) Source acceptance testing and QA a) calibration and source strength specification standards b) leakage tests and source geometry verification (2) Applicator acceptance testing and QA (3) Remote afterloading devices (4) Treatment planning systems a) graphic input/output devices, implant geometry reconstruction, and graphical display b) dose calculation accuracy i) review of brachytherapy dose calculation algorithms ii) dosimetric benchmarks available: Task Group 43 report (C) Procedure-specific QA 1) Organization of treatment delivery team 2) Preplanning and preparation 3) Applicator insertion 4) Radiographic examination of the implant, prescription, and treatment calculation 5) Source insertion 6) Treatment planning and physicist review of treatment plans 7) QA during patient treatment and removal of sources and applicators

  10. A brachytherapy model-based dose calculation algorithm -AMIGOBrachy

    International Nuclear Information System (INIS)

    Brachytherapy treatments have been performed based on TG-43U1 water dose formalism which neglects human tissues density and composition, body interfaces and applicator effects. As these effects could be relevant for brachytherapy energy range, modern treatment planning systems (TPS) are now available that are based on model-based dose calculation algorithms (MBDCA) enabling heterogeneity corrections, which are needed to replace the TG-43U1 water dose formalism for a more accurate approach. The recently published AAPM TG-186 report is the first step towards to a TPS taking into account heterogeneities, applicators and human body complexities. This report presents the current status, recommendations for clinical implementation and specifies research areas where considerable efforts are necessary to move forward with MBDCA. Monte Carlo (MC) codes are an important part of the current algorithms due their flexibility and accuracy, although, almost all MC codes present no interface to process the large amount of data necessary to perform clinical cases simulations, which may include hundreds of dwell positions, inter-seed attenuation, image processing and others time consuming issues that can make MC simulation unfeasible without a pre-processing interface. This work presents the AMIGOBrachy interface tool (Algorithm for Medical Image-based Generating Object - Brachytherapy module) which provides all the pre-processing task needed for the simulation. This software can import and edit treatments plans from BrachyVision™ (Varian Medical Systems, Inc., Palo Alto, CA) and ONCENTRA™ (Elekta AB, Stockholm, Sweden), and also create a new plan through contouring resources, needle recognition, HU segmentation, combining voxels phantoms with analytical geometries to define applicators and other resources used to create MCNP5 input and analyze the results. This work presents some results used to validate the software and to evaluate the heterogeneities impact in a clinical case

  11. Brachytherapy dose measurements in heterogeneous tissues

    Energy Technology Data Exchange (ETDEWEB)

    Paiva F, G.; Luvizotto, J.; Salles C, T.; Guimaraes A, P. C.; Dalledone S, P. de T.; Yoriyaz, H. [Instituto de Pesquisas Energeticas e Nucleares / CNEN, Av. Lineu Prestes 2242, Cidade Universitaria, 05508-000 Sao Paulo (Brazil); Rubo, R., E-mail: gabrielpaivafonseca@gmail.com [Hospital das Clinicas da Faculdade de Medicina da Universidade de Sao Paulo, 05403-900 Sao Paulo (Brazil)

    2014-08-15

    Recently, Beau lieu et al. published an article providing guidance for Model-Based Dose Calculation Algorithms (MBDCAs), where tissue heterogeneity considerations are addressed. It is well-known that T G-43 formalism which considers only water medium is limited and significant dose differences have been found comparing both methodologies. The aim of the present work is to experimentally quantify dose values in heterogeneous medium using different dose measurement methods and techniques and compare them with those obtained with Monte Carlo simulations. Experiments have been performed using a Nucletron micro Selectron-Hdr Ir-192 brachytherapy source and a heterogeneous phantom composed by PMMA and different tissue equivalent cylinders like bone, lungs and muscle. Several dose measurements were obtained using tissue equivalent materials with height 1.8 cm and 4.3 cm positioned between the radiation source and the detectors. Radiochromic films, TLDs and MOSFET S have been used for the dose measurements. Film dosimetry has been performed using two methodologies: a) linearization for dose-response curve based on calibration curves to create a functional form that linearize s the dose response and b) 177 multichannel analysis dosimetry where the multiple color channels are analyzed allowing to address not only disturbances in the measurements caused by thickness variation in the film layer, but also, separate other external influences in the film response. All experiments have been simulated using the MCNP5 Monte Carlo radiation transport code. Comparison of experimental results are in good agreement with calculated dose values with differences less than 6% for almost all cases. (Author)

  12. Brachytherapy dose measurements in heterogeneous tissues

    International Nuclear Information System (INIS)

    Recently, Beau lieu et al. published an article providing guidance for Model-Based Dose Calculation Algorithms (MBDCAs), where tissue heterogeneity considerations are addressed. It is well-known that T G-43 formalism which considers only water medium is limited and significant dose differences have been found comparing both methodologies. The aim of the present work is to experimentally quantify dose values in heterogeneous medium using different dose measurement methods and techniques and compare them with those obtained with Monte Carlo simulations. Experiments have been performed using a Nucletron micro Selectron-Hdr Ir-192 brachytherapy source and a heterogeneous phantom composed by PMMA and different tissue equivalent cylinders like bone, lungs and muscle. Several dose measurements were obtained using tissue equivalent materials with height 1.8 cm and 4.3 cm positioned between the radiation source and the detectors. Radiochromic films, TLDs and MOSFET S have been used for the dose measurements. Film dosimetry has been performed using two methodologies: a) linearization for dose-response curve based on calibration curves to create a functional form that linearize s the dose response and b) 177 multichannel analysis dosimetry where the multiple color channels are analyzed allowing to address not only disturbances in the measurements caused by thickness variation in the film layer, but also, separate other external influences in the film response. All experiments have been simulated using the MCNP5 Monte Carlo radiation transport code. Comparison of experimental results are in good agreement with calculated dose values with differences less than 6% for almost all cases. (Author)

  13. In-phantom dosimetric measurements as quality control for brachytherapy. System check and constancy check; Messungen im Festkoerperphantom als Qualitaetskontrolle in der Brachytherapie. Systempruefung und Konstanzpruefung

    Energy Technology Data Exchange (ETDEWEB)

    Kollefrath, Michael; Bruggmoser, Gregor; Nanko, Norbert; Gainey, Mark [Universitaetsklinik Freiburg (Germany). Klinik fuer Strahlenheilkunde

    2015-09-01

    In brachytherapy dosimetric measurements are difficult due to the inherent dose-inhomogeneities. Typically in routine clinical practice only the nominal dose rate is determined for computer controlled afterloading systems. The region of interest lies close to the source when measuring the spatial dose distribution. In this region small errors in the positioning of the detector, and its finite size, lead to large measurement uncertainties that exacerbate the routine dosimetric control of the system in the clinic. The size of the measurement chamber, its energy dependence, and the directional dependence of the measurement apparatus are the factors which have a significant influence on dosimetry. Although ionisation chambers are relatively large, they are employed since similar chambers are commonly found on clinical brachytherapy units. The dose is determined using DIN 6800 [11] since DIN 6809-2 [12], which deals with dosimetry in brachytherapy, is antiquated and is currently in the process of revision. Further information regarding dosimetry for brachytherapy can be found in textbooks [1] and [2]. The measurements for this work were performed with a HDR (High-Dose-Rate) {sup 192}Ir source, type mHDR V2, and a Microselectron Afterloader V2 both from Nucletron/Elekta. In this work two dosimetric procedures are presented which, despite the aforemention difficulties, should assist in performing checks of the proper operation of the system. The first is a system check that measures the dose distribution along a line and is to be performed when first bringing the afterloader into operation, or after significant changes to the system. The other is a dosimetric constancy check, which with little effort can be performed monthly or weekly. It simultaneously verifies the positioning of the source at two positions, the functionality of the system clock and the automatic re-calculation of the source activity.

  14. Comparison of dose calculation methods for brachytherapy of intraocular tumors

    Energy Technology Data Exchange (ETDEWEB)

    Rivard, Mark J.; Chiu-Tsao, Sou-Tung; Finger, Paul T.; Meigooni, Ali S.; Melhus, Christopher S.; Mourtada, Firas; Napolitano, Mary E.; Rogers, D. W. O.; Thomson, Rowan M.; Nath, Ravinder [Department of Radiation Oncology, Tufts University School of Medicine, Boston, Massachusetts 02111 (United States); Quality MediPhys LLC, Denville, New Jersey 07834 (United States); New York Eye Cancer Center, New York, New York 10065 (United States); Department of Radiation Oncology, Comprehensive Cancer Center of Nevada, Las Vegas, Nevada 89169 (United States); Department of Radiation Oncology, Tufts University School of Medicine, Boston, Massachusetts 02111 (United States); Department of Radiation Physics, University of Texas, M.D. Anderson Cancer Center, Houston, Texas 77030 (United States) and Department of Experimental Diagnostic Imaging, University of Texas, M.D. Anderson Cancer Center, Houston, Texas 77030 (United States); Physics, Elekta Inc., Norcross, Georgia 30092 (United States); Department of Physics, Carleton University, Ottawa, Ontario K1S 5B6 (Canada); Department of Therapeutic Radiology, Yale University School of Medicine, New Haven, Connecticut 06520 (United States)

    2011-01-15

    Purpose: To investigate dosimetric differences among several clinical treatment planning systems (TPS) and Monte Carlo (MC) codes for brachytherapy of intraocular tumors using {sup 125}I or {sup 103}Pd plaques, and to evaluate the impact on the prescription dose of the adoption of MC codes and certain versions of a TPS (Plaque Simulator with optional modules). Methods: Three clinical brachytherapy TPS capable of intraocular brachytherapy treatment planning and two MC codes were compared. The TPS investigated were Pinnacle v8.0dp1, BrachyVision v8.1, and Plaque Simulator v5.3.9, all of which use the AAPM TG-43 formalism in water. The Plaque Simulator software can also handle some correction factors from MC simulations. The MC codes used are MCNP5 v1.40 and BrachyDose/EGSnrc. Using these TPS and MC codes, three types of calculations were performed: homogeneous medium with point sources (for the TPS only, using the 1D TG-43 dose calculation formalism); homogeneous medium with line sources (TPS with 2D TG-43 dose calculation formalism and MC codes); and plaque heterogeneity-corrected line sources (Plaque Simulator with modified 2D TG-43 dose calculation formalism and MC codes). Comparisons were made of doses calculated at points-of-interest on the plaque central-axis and at off-axis points of clinical interest within a standardized model of the right eye. Results: For the homogeneous water medium case, agreement was within {approx}2% for the point- and line-source models when comparing between TPS and between TPS and MC codes, respectively. For the heterogeneous medium case, dose differences (as calculated using the MC codes and Plaque Simulator) differ by up to 37% on the central-axis in comparison to the homogeneous water calculations. A prescription dose of 85 Gy at 5 mm depth based on calculations in a homogeneous medium delivers 76 Gy and 67 Gy for specific {sup 125}I and {sup 103}Pd sources, respectively, when accounting for COMS-plaque heterogeneities. For off

  15. Influence of trace elements in human tissue in low-energy photon brachytherapy dosimetry

    International Nuclear Information System (INIS)

    The aim of this paper is to determine the dosimetric impact of trace elements in human tissues for low-energy photon sources used in brachytherapy. Monte Carlo dose calculations were used to investigate the dosimetric effect of trace elements present in normal or cancerous human tissues. The effect of individual traces (atomic number Z = 11–30) was studied in soft tissue irradiated by low-energy brachytherapy sources. Three other tissue types (prostate, adipose and mammary gland) were also simulated with varying trace concentrations to quantify the contribution of each trace to the dose distribution. The dose differences between cancerous and healthy prostate tissues were calculated in single- and multi-source geometries. The presence of traces in a tissue produces a difference in the dose distribution that is dependent on Z and the concentration of the trace. Low-Z traces (Na) have a negligible effect (3%). There is a potentially significant difference in the dose distribution between cancerous and healthy prostate tissues (4%) and even larger if compared to the trace-free composition (15%) in both single- and multi-sourced geometries. Trace elements have a non-negligible (up to 8% in prostate D90) effect on the dose in tissues irradiated with low-energy photon sources. This study underlines the need for further investigation into accurate determination of the trace composition of tissues associated with low-energy brachytherapy. Alternatively, trace elements could be incorporated as a source of uncertainty in dose calculations. (paper)

  16. ACPSEM brachytherapy working group recommendations for quality assurance in brachytherapy

    International Nuclear Information System (INIS)

    The Australasian College of Physical Scientists and Engineers in Medicine (ACPSEM) Radiation Oncology Specialty Group (ROSG) formed a series of working groups in 2011 to develop recommendation papers for guidance of radiation oncology medical physics practice within the Australasian setting. These recommendations are intended to provide guidance for safe work practices and a suitable level of quality control without detailed work instructions. It is the responsibility of the medical physicist to ensure that locally available equipment and procedures are sufficiently sensitive to establish compliance to these recommendations. The recommendations are endorsed by the ROSG, have been subject to independent expert reviews and have also been approved by the ACPSEM Council. For the Australian audience, these recommendations should be read in conjunction with the Tripartite Radiation Oncology Practice Standards. This publication presents the recommendations of the ACPSEM Brachytherapy Working Group (BTWG) and has been developed in alignment with other international associations. However, these recommendations should be read in conjunction with relevant national, state or territory legislation and local requirements, which take precedence over the ACPSEM recommendation papers. It is hoped that the users of this and other ACPSEM recommendation papers will contribute to the development of future versions through the Radiation Oncology Specialty Group of the ACPSEM.

  17. On the Development of a Miniature Neutron Generator for the Brachytherapy Treatment of Cancer

    Science.gov (United States)

    Forman, L.

    2009-03-01

    Brachytherapy refers to application of an irradiation source within a tumor. 252Cf needles used in brachytherapy have been successfully applied to treatment of some of the most virulent cancers but it is doubtful that it will be widely used because of difficulty in dealing with unwanted dose (source cannot be turned off) and in adhering to stringent NRC regulations that have been exacerbated in our post 911 environment. We have been working on the development of a miniature neutron generator with the reaction target placed at the end of a needle (tube) for brachytherapy applications. Orifice geometries are most amenable, e.g. rectum and cervix, but interstitial use is possible with microsurgery. This paper dicusses the results of a 30 watt DD neutron generator SBU project that demonstrates that sufficient hydrogen isotope current can be delivered down a small diameter needle required for a DT neutron treatment device, and, will summarize the progress of building a commercial device pursued by the All Russian Institute for Automatics (VNIIA) supported by the DOE's Industrial Proliferation Prevention Program (IPP). It is known that most of the fast neutron (FN) beam cancer treatment facilities have been closed down. It appears that the major limitation in the use of FN beams has been damage to healthy tissue, which is relatively insensitive to photons, but this problem is alleviated by brachytherapy. Moreover, recent clinical results indicate that fast neutrons in the boost mode are most highly effective in treating large, hypoxic, and rapidly repopulating diseases. It appears that early boost application of FN may halt angiogenesis (development and repair of tumor vascular system) and shrink the tumor resulting in lower hypoxia. The boost brachytherapy application of a small, low cost neutron generator holds promise of significant contribution to the treatment of cancer.

  18. Investigation of palladium-103 production and IR07-103Pd brachytherapy seed preparation

    International Nuclear Information System (INIS)

    Highlights: → We report the cyclotron production of 103-palladium via 103Rh(p,n)103Pd reaction. → 103Pd was absorbed on resin beads for brachytherapy seed preparation. → The optimum absorption of 103Pd in resin was achieved at 0.5 M HCl. → Version 5 of MCNP code was employed to model a new 103Pd brachytherapy seed. - Abstract: In this study, design and fabrication of 103Pd brachytherapy seed was investigated. The excitation functions of 103Rh(p,n)103Pd and 103Rh(d,2n)103Pd reactions were calculated using EMPIRE (version 3.1 Rivoli), ALICE/ASH and TALYS-1.2 codes, the TENDL-2010 database and compared with the published data. Production of 103Pd was done via 103Rh(p,n)103Pd nuclear reaction. The target was bombarded with 18 MeV protons at 200 μA beam current for 15 h. After irradiation and radiochemical separation of the electroplated rhodium target, the optimum condition for absorption of 103Pd into Amberlite (registered) IR-93 resin was achieved at 0.5 M HCl. Version 5 of the (MCNP) Monte Carlo radiation transport code was employed to calculate the dosimetric parameters around the 103Pd brachytherapy seed. Finally the calculated results were compared with published results for other commercial sources.

  19. Progress and review of brachytherapy for cancer of the oral region

    International Nuclear Information System (INIS)

    Radiation therapy contributes greatly to the treatment of head and neck cancer, because it maintains the normal anatomy, minimizes functional loss, and facilitates a patient's return to work. Brachytherapy using small radiation sources is an indispensable modality for the treatment of cancer of the oral region, in which emphasis should be laid on the maintenance of normal anatomy and function and a high quality of life. Brachytherapy was performed in 62% of the radiation therapy patients with cancer of the oral region. Interstitial brachytherapy with radium, 192Ir-hairpin was administered to more than 80% of the patients with tongue cancer and 198Au-grain was frequently used for other site of the oral region. Introduction of the remote afterloading system (RALS) has completely eliminated the possibility of personnel exposure and increased the indication for brachytherapy. There is a lot of work to be done in the near future, including the establishment of dose-time relationship for RALS and the development of related apparatus and instruments and the standardization of dose assessment. (author)

  20. Brachytherapy Application With In Situ Dose Painting Administered by Gold Nanoparticle Eluters

    Energy Technology Data Exchange (ETDEWEB)

    Sinha, Neeharika [Department of Sciences, Wentworth Institute of Technology, Boston, Massachusetts (United States); Cifter, Gizem [Department of Physics and Applied Physics, University of Massachusetts, Lowell, Massachusetts (United States); Department of Radiation Oncology, Dana-Farber Cancer Institute, Brigham and Women' s Hospital and Harvard Medical School, Boston, Massachusetts (United States); Sajo, Erno [Department of Physics and Applied Physics, University of Massachusetts, Lowell, Massachusetts (United States); Kumar, Rajiv; Sridhar, Srinivas [Department of Radiation Oncology, Dana-Farber Cancer Institute, Brigham and Women' s Hospital and Harvard Medical School, Boston, Massachusetts (United States); Electronic Materials Research Institute and Department of Physics, Northeastern University, Boston, Massachusetts (United States); Nguyen, Paul L.; Cormack, Robert A.; Makrigiorgos, G. Mike [Department of Radiation Oncology, Dana-Farber Cancer Institute, Brigham and Women' s Hospital and Harvard Medical School, Boston, Massachusetts (United States); Ngwa, Wilfred, E-mail: wngwa@lroc.harvard.edu [Department of Physics and Applied Physics, University of Massachusetts, Lowell, Massachusetts (United States); Department of Radiation Oncology, Dana-Farber Cancer Institute, Brigham and Women' s Hospital and Harvard Medical School, Boston, Massachusetts (United States)

    2015-02-01

    Purpose: Recent studies show promise that administering gold nanoparticles (GNP) to tumor cells during brachytherapy could significantly enhance radiation damage to the tumor. A new strategy proposed for sustained administration of the GNP in prostate tumors is to load them into routinely used brachytherapy spacers for customizable in situ release after implantation. This in silico study investigated the intratumor biodistribution and corresponding dose enhancement over time due to GNP released from such GNP-loaded brachytherapy spacers (GBS). Method and Materials: An experimentally determined intratumoral diffusion coefficient (D) for 10-nm nanoparticles was used to estimate D for other sizes by using the Stokes-Einstein equation. GNP concentration profiles, obtained using D, were then used to calculate the corresponding dose enhancement factor (DEF) for each tumor voxel, using dose painting-by-numbers approach, for times relevant to the considered brachytherapy sources' lifetimes. The investigation was carried out as a function of GNP size for the clinically applicable low-dose-rate brachytherapy sources iodine-125 (I-125), palladium-103 (Pd-103), and cesium-131 (Cs-131). Results: Results showed that dose enhancement to tumor voxels and subvolumes during brachytherapy can be customized by varying the size of GNP released or eluted from the GBS. For example, using a concentration of 7 mg/g GNP, significant DEF (>20%) could be achieved 5 mm from a GBS after 5, 12, 25, 46, 72, 120, and 195 days, respectively, for GNP sizes of 2, 5, 10, 20, 30, and 50 nm and for 80 nm when treating with I-125. Conclusions: Analyses showed that using Cs-131 provides the highest dose enhancement to tumor voxels. However, given its relatively longer half-life, I-125 presents the most flexibility for customizing the dose enhancement as a function of GNP size. These findings provide a useful reference for further work toward development of potential new brachytherapy application

  1. Brachytherapy Application With In Situ Dose Painting Administered by Gold Nanoparticle Eluters

    International Nuclear Information System (INIS)

    Purpose: Recent studies show promise that administering gold nanoparticles (GNP) to tumor cells during brachytherapy could significantly enhance radiation damage to the tumor. A new strategy proposed for sustained administration of the GNP in prostate tumors is to load them into routinely used brachytherapy spacers for customizable in situ release after implantation. This in silico study investigated the intratumor biodistribution and corresponding dose enhancement over time due to GNP released from such GNP-loaded brachytherapy spacers (GBS). Method and Materials: An experimentally determined intratumoral diffusion coefficient (D) for 10-nm nanoparticles was used to estimate D for other sizes by using the Stokes-Einstein equation. GNP concentration profiles, obtained using D, were then used to calculate the corresponding dose enhancement factor (DEF) for each tumor voxel, using dose painting-by-numbers approach, for times relevant to the considered brachytherapy sources' lifetimes. The investigation was carried out as a function of GNP size for the clinically applicable low-dose-rate brachytherapy sources iodine-125 (I-125), palladium-103 (Pd-103), and cesium-131 (Cs-131). Results: Results showed that dose enhancement to tumor voxels and subvolumes during brachytherapy can be customized by varying the size of GNP released or eluted from the GBS. For example, using a concentration of 7 mg/g GNP, significant DEF (>20%) could be achieved 5 mm from a GBS after 5, 12, 25, 46, 72, 120, and 195 days, respectively, for GNP sizes of 2, 5, 10, 20, 30, and 50 nm and for 80 nm when treating with I-125. Conclusions: Analyses showed that using Cs-131 provides the highest dose enhancement to tumor voxels. However, given its relatively longer half-life, I-125 presents the most flexibility for customizing the dose enhancement as a function of GNP size. These findings provide a useful reference for further work toward development of potential new brachytherapy application

  2. Brachytherapy on treatment of childhood rhabdomyosarcoma

    International Nuclear Information System (INIS)

    A retrospective study of 21 children with rhabdomyosarcoma treated by brachytherapy to the primary site of the tumor between january/1980 to june/1993 was undertaken. The main objectives were: to comprove the utility of brachytherapy in childhood rhabdomyosarcoma, to evaluate the local control and survival in association with chemotherapy, to analyze the late effects of the treatment and to determinate the preferencial technique to each clinical situation. Seventeen patients were female and four male with a median age of five years (range of 3 months to 15 years). Seven children showed head and neck tumors, seven in extremities, five genital, one perineal and one in trunk. Four patients were group II, fifteen group III and two group IV according the Intergroup Rhabdomyosarcoma Study (IRS) classification. The histologic type presented eighteen embryonary rhabdomyosarcoma, one alveolar rhabdomyosarcoma and in two patients was not possible to be determined. The therapeutic approach included induction chemotherapy followed by radiotherapy to the primary site in association or not with surgical ressection and maintenance chemotherapy. All patients received brachytherapy to the tumor site. The radioactive isotopes employed were: Gold198, Cesium137 and Iridium192. The brachytherapy techniques depended on the tumor site, period of treatment, availability of the radioactive material and stage of the disease. Patients treated exclusively by brachytherapy received 40Gy to 60Gy. When brachytherapy was associated with external radiotherapy the dose ranged from 20Gy to 40Gy. Local control was achieved in 18 of 20 patients (90%). The global survival and local control survival rates were 61.9% ((13(21)) patients) and 72.2% ((13(18)) patients) respectively. Staging and age showed statistic significance for survival. Distant metastasis occurred in seven patients (33.3%), mainly to the lungs. Patients treated with total radiation dose higher than 45Gy showed more incidence of

  3. Factors affecting radiation injury after interstitial brachytherapy for brain tumors

    International Nuclear Information System (INIS)

    The effects of brachytherapy on normal brain tissue are not easily delineated in the clinical setting because of the presence of concurrent radiation-induced changes in the coexistent brain tumor. Sequential morphologic studies performed after the implantation of radioactive sources into the brains of experimental animals have provided a better understanding of the character and magnitude of the structural changes produced by interstitial irradiation on normal brain tissue. Furthermore, the clinical experience accumulated thus far provides not only relevant information, but also some guidelines for future treatment policies. In this paper, the authors summarize the experimental findings and review the pathologic and clinical features of brain injury caused by interstitial brachytherapy. A number of studies in the older literature examined the effects of radioisotopes such as radium-226 (38--43), radon-22 (44--46), gold-198 (29,47--50), tantalum-182 (29,51,52) yttrium-9- (50,53,54), and cobalt-60 (29,50,55). This review is restricted to low- and high-activity encapsulated iodine-125 (125I) and iridium-192 (192Ir), the isotopes that are most commonly used in current clinical practice

  4. The present state of brachytherapy practice in the Czech Republic

    International Nuclear Information System (INIS)

    In spite of the fact that radiotherapy departments in the Czech republic have been following the general European and world trends in brachytherapy techniques and that they are installing the new remote AFL systems, the reserves of radium sources are still considerably high and not all professionals carry out their applications of radioactive sources by (at least) manual AFL. In near future the attention should be paid to the diminution of the unnecessary radium reserves at that radiotherapy departments where the small number of applications is executed or where the new remote AFL systems are used. For professionals practically thorough radiation protection is assured when new remote AFL systems are used. But in this case an attention should be paid to the radiation safety of the patient because of the potential exposures when high dose rate systems would failed. The likelihood of this unwanted cases can only be decreased when Quality Assurance programs is introduced into practice

  5. Characterization of TLD-100 in powders for dosimetric quality control of {sup 192} Ir sources used in brachytherapy of high dose rate; Caracterizacion de TLD-100 en polvo para control de calidad dosimetrico de fuentes de Ir{sup 192} usadas en braquiterapia de alta tasa de dosis

    Energy Technology Data Exchange (ETDEWEB)

    Loaiza C, S.P

    2007-07-01

    The Secondary Standard Dosimetric at the National Institute of Nuclear Research (ININ) calibrated a lot of powdered TLD-100 (LiF:Mg,Ti) in terms of absorbed dose to water D{sub w} for the energy of: {sup 60}Co, {sup 137C}s, X rays of 250 and 50 kVp. Later on, it is carried out an interpolation of the calibration for the energy of the {sup 192}Ir. This calibration is part of a dosimetric quality control program, to solve the problems of traceability for the measurements carried out by the users of {sup 192}Ir sources employed in the treatments of High Dose Rate Brachytherapy (HDR) at the Mexican Republic. The calibrations of the radiation beams are made with the following protocols: IAEA TRS-398 for the {sup 60}Co for D{sub w}, using a secondary standard ionization chamber PTW N30013 calibrated in D{sub w} by the National Research Council (NRC, Canada). AAPM TG-43 for D{sub w} in terms of the strength kerma Sk, calibrating this last one quantity for the {sup 137}Cs radioactive source, with a well chamber HDR 1000 PLUS traceable to the University of Wisconsin (US). AAPM TG-61 for X ray of 250 and 50 kVp for D{sub w} start to Ka using field standard a Farmer chamber PTW 30001 traceable to K for the Central Laboratory of Electric Industries (CLEI, France). The calibration curves (CC) they built for the response of the powder TLD: R{sub TLD} vs D{sub w}: For the energy of {sup 60}Co, {sup 137}Cs, X rays of 250 and 50 kVp. Fitting them with the least square method weighed by means of a polynomial of second grade that corrects the supra linearity of the response. iii. Each one of the curves was validated with a test by lack of fitting and for the Anderson Darling normality test, using the software MINITAB in both cases. iv. The sensibility factor (F{sub s}) for each energy corresponds to the slope of the CC, v. The F{sub s} for the two {sup 192}Ir sources used are interpolated: one for a Micro Selectron source and the other one a Vari Source source. Finally, a couple of

  6. Study and parameters survey for iodine-125 source dosimetry to be applied in brachytherapy; Estudo e levantamentos de parametros para dosimetria de fontes de iodo-125 aplicadas em braquiterapia

    Energy Technology Data Exchange (ETDEWEB)

    Moura, Eduardo Santana de

    2011-07-01

    The use of brachytherapy technique with iodine-125 seeds to prostate cancer treatment has been used for decades with good clinical outcomes. To aim the Brazilian population necessities, IPEN-CNEN/SP developed the iodine-125 seed prototype with national technology. The objectives of this work are the development and the study of dosimetric procedures associates with the experimental acquisition of the useful parameters for the iodine-125 dosimetric characterization and to evaluate if the developed procedures, in this work, have the basic conditions to determinate the dosimetric analysis, that are fundamental for clinical procedures. The dosimeters selected for the analysis are the TLD-100 (LiF:Mg,Ti), initially these dosimeters were submitted for two selection steps to choose the dosimeters more reproducible for the dosimetric analysis. The two steps were the selection by the mass of the dosimeters and the reproducibility after four irradiation series in a Cobalt-60 irradiator (CTR-IPEN). Afterwards these steps, the dosimeters were irradiated in linear accelerator with 6 MV energy (Service of Radiotherapy - Hospital Israelita Albert Einstein) to yield the individual calibration factors to each dosimeter. After, the dosimeters were used to the irradiations with iodine-125 seed, 6711 model, (GE-Healthcare). The irradiations and others analysis with iodine-125 seeds yield the useful values for the determination of the parameters suggested by the AAPM (American Association of Physicists in Medicine): constant of dose rate, geometry function, dose radial function and anisotropy function. The results showed good agreement with the values published by the literature, for the same iodine- 125 model, this fact confirms that the realized parameters will be able to be used for the IPEN-CNEN iodine-125 seeds dosimetry and quality control. (author)

  7. SU-E-T-366: Clinical Implementation of MR-Guided Vaginal Cylinder Brachytherapy

    International Nuclear Information System (INIS)

    Purpose: To evaluate the accuracy of MR-based vaginal brachytherapy source localization using an in-house MR-visible marker versus the alignment of an applicator model to MR images. Methods: Three consecutive patients undergoing vaginal HDR brachytherapy with a plastic cylinder were scanned with both CT and MRI (including T1- and T2- weighted images). An MR-visible source localization marker, consisting of a sealed thin catheter filled with either water (for T2 contrast) or Gd-doped water (for T1 contrast), was assembled shortly before scanning. Clinically, the applicator channel was digitized on CT with an x-ray marker. To evaluate the efficacy of MR-based applicator reconstruction, each MR image volume was aligned locally to the CT images based on the region containing the cylinder. Applicator digitization was performed on the MR images using (1) the MR visible marker and (2) alignment of an applicator surface model from Varian's Brachytherapy Planning software to the MRI images. Resulting source positions were compared with the original CT digitization. Results: Although the source path was visualized by the MR marker, the applicator tip proved difficult to identify due to challenges in achieving a watertight seal. This resulted in observed displacements of the catheter tip, at times >1cm. Deviations between the central source positions identified via aligning the applicator surface model to MR and using the xray marker on CT ranged from 0.07 – 0.19 cm and 0.07 – 0.20 cm on T1- weighted and T2-weighted images, respectively. Conclusion: Based on the current study, aligning the applicator model to MRI provides a practical, current approach to perform MR-based brachytherapy planning. Further study is needed to produce catheters with reliably and reproducibly identifiable tips. Attempts are being made to improve catheter seals, as well as to increase the viscosity of the contrast material to decrease fluid mobility inside the catheter

  8. SU-E-T-447: Electronic Brachytherapy (EBT) Treatment of Cervical Cancer - First Clinical Experience

    Energy Technology Data Exchange (ETDEWEB)

    Johnson, D; Johnson, M; Thompson, J; Ahmad, S [University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma (United States); Chan, L; Hausen, H [Xoft Inc., San Jose, CA (United States)

    2014-06-01

    Purpose: To study the first trial patient in which an electronic brachytherapy (EBT) x-ray source is utilized for treatment of cervical cancer. Methods: During patient treatment, a miniaturized x-ray source was used in combination with a customized titanium tandem and ovoid applicator set. The semi-specialized source was modeled with formalisms outlined by AAMP Task Group 43. Multiple models were used to compensate for variable attenuation conditions as a function of source positions. Varian Brachyvision treatment planning software was utilized on CT data sets for dose calculations prior to treatment delivery. The dose was prescribed to “point A” as defined by American Brachytherapy society. Additional treatments plans were created from those clinically utilized in patient care and were recalculated for an existing Ir-192 source model. Dose volume histograms (DVH) and point dose calculations were compared between the modalities for the clinical condition present in patients treated with EBT. Results: Clinical treatment times, though longer than those typically experienced by Ir-192 users, were manageable. Instantaneous dose rates at personal positions within the treatment vault were lower than those measured during intra operative radiation therapy and breast EBT treatments. Due to lower average photon energy in EBT, dose gradients within the treatment plans were as expected steeper than those observed in Ir-192 based brachytherapy. DVH comparisons between Ir-192 and EBT treatments showed an expected decrease in the integral dose to normal tissues of interest for EBT. In comparing plans created for EBT delivery with those calculated for Ir-192, average dose values for EBT were more than 4%, 11%, and 9% lower at predefined bladder, rectum and “point B” positions, respectively. Conclusion: For the first time, we have demonstrated that the utilizing electronic brachytherapy system for tandem and ovoid based treatment of cancer of the cervix is feasible, and

  9. SU-E-T-447: Electronic Brachytherapy (EBT) Treatment of Cervical Cancer - First Clinical Experience

    International Nuclear Information System (INIS)

    Purpose: To study the first trial patient in which an electronic brachytherapy (EBT) x-ray source is utilized for treatment of cervical cancer. Methods: During patient treatment, a miniaturized x-ray source was used in combination with a customized titanium tandem and ovoid applicator set. The semi-specialized source was modeled with formalisms outlined by AAMP Task Group 43. Multiple models were used to compensate for variable attenuation conditions as a function of source positions. Varian Brachyvision treatment planning software was utilized on CT data sets for dose calculations prior to treatment delivery. The dose was prescribed to “point A” as defined by American Brachytherapy society. Additional treatments plans were created from those clinically utilized in patient care and were recalculated for an existing Ir-192 source model. Dose volume histograms (DVH) and point dose calculations were compared between the modalities for the clinical condition present in patients treated with EBT. Results: Clinical treatment times, though longer than those typically experienced by Ir-192 users, were manageable. Instantaneous dose rates at personal positions within the treatment vault were lower than those measured during intra operative radiation therapy and breast EBT treatments. Due to lower average photon energy in EBT, dose gradients within the treatment plans were as expected steeper than those observed in Ir-192 based brachytherapy. DVH comparisons between Ir-192 and EBT treatments showed an expected decrease in the integral dose to normal tissues of interest for EBT. In comparing plans created for EBT delivery with those calculated for Ir-192, average dose values for EBT were more than 4%, 11%, and 9% lower at predefined bladder, rectum and “point B” positions, respectively. Conclusion: For the first time, we have demonstrated that the utilizing electronic brachytherapy system for tandem and ovoid based treatment of cancer of the cervix is feasible, and

  10. Predictive factors for late toxicity after endobronchial brachytherapy: a multivariate analysis

    International Nuclear Information System (INIS)

    Purpose: To determine the predictive factors associated with hemoptysis and radiation bronchitis after endobronchial brachytherapy by univariate and multivariate analyses Methods and Materials: One hundred forty-nine patients underwent endobronchial brachytherapy and were divided into three therapeutic groups: group 1: patients treated with palliative intent (n = 47); group 2: patients treated with curative intent (small endobronchial tumors without mediastinal or general dissemination: n = 73); group 3: patients also receiving external irradiation (n = 29). One hundred twelve patients had previously received external irradiation. Brachytherapy was delivered with a dose per fraction ranging from 4 to 7 Gy and a prescription point between 0.5 and 1.5 cm, usually 1 cm from the source center. Two to six fractions were delivered according to the therapeutic group and clinical situation. The influence of the following variables on the incidence of hemoptysis or radiation bronchitis was studied: age, sex, Karnofsky score, therapeutic group, histologic type, endoscopic tumor length, dose per fraction, total brachytherapy dose, total external beam irradiation dose, total dose (brachytherapy dose plus external irradiation dose), volumes of the 100% and 200% isodoses, and volumes of the 7 and 14 Gy isodoses. Results: We observed 11 hemoptyses (7.4%), 10 were lethal. All but one occurred in patients with progressive disease. Two clinical factors were significantly associated with hemoptysis by univariate analysis: palliative group (p = 0.009) and endobronchial tumor length (p = 0.004). No technical factors seem to be implicated in the occurrence of hemoptysis. Only endobronchial tumor length remained in the multivariate model (p = 0.02). Radiation bronchitis was observed in 13 cases (8.7%). By univariate analysis, a good Karnofsky score (p = 0.02), curative treatment (p = 0.02), and tumor location on trachea and main stem bronchus (p = 0.002) were significantly associated

  11. EM-navigated catheter placement for gynecologic brachytherapy: an accuracy study

    Science.gov (United States)

    Mehrtash, Alireza; Damato, Antonio; Pernelle, Guillaume; Barber, Lauren; Farhat, Nabgha; Viswanathan, Akila; Cormack, Robert; Kapur, Tina

    2014-03-01

    Gynecologic malignancies, including cervical, endometrial, ovarian, vaginal and vulvar cancers, cause significant mortality in women worldwide. The standard care for many primary and recurrent gynecologic cancers consists of chemoradiation followed by brachytherapy. In high dose rate (HDR) brachytherapy, intracavitary applicators and /or interstitial needles are placed directly inside the cancerous tissue so as to provide catheters to deliver high doses of radiation. Although technology for the navigation of catheters and needles is well developed for procedures such as prostate biopsy, brain biopsy, and cardiac ablation, it is notably lacking for gynecologic HDR brachytherapy. Using a benchtop study that closely mimics the clinical interstitial gynecologic brachytherapy procedure, we developed a method for evaluating the accuracy of image-guided catheter placement. Future bedside translation of this technology offers the potential benefit of maximizing tumor coverage during catheter placement while avoiding damage to the adjacent organs, for example bladder, rectum and bowel. In the study, two independent experiments were performed on a phantom model to evaluate the targeting accuracy of an electromagnetic (EM) tracking system. The procedure was carried out using a laptop computer (2.1GHz Intel Core i7 computer, 8GB RAM, Windows 7 64-bit), an EM Aurora tracking system with a 1.3mm diameter 6 DOF sensor, and 6F (2 mm) brachytherapy catheters inserted through a Syed-Neblett applicator. The 3D Slicer and PLUS open source software were used to develop the system. The mean of the targeting error was less than 2.9mm, which is comparable to the targeting errors in commercial clinical navigation systems.

  12. Interstitial high dose rate brachytherapy for cancer of the oral tongue

    International Nuclear Information System (INIS)

    Between October 1992 and March 1996, 34 patients with cancer of the tongue without nodal metastases underwent fractionated interstitial brachytherapy with a high dose rate (HDR) iridium remote afterloader. The types of treatment consisted of brachytherapy (BT) alone: 8 cases, BT after surgery: 3 cases, BT after systemic chemotherapy: 3 cases, BT after arterial infusion (AI): 14 cases, BT after external beam radiotherapy (ERT): 5 cases, and BT after AI+ERT: 1 case. Applicators were implanted under general anesthesia. Reference dose was estimated at point 5 mm from source. Brachytherapy was carried out in 10 fractions twice a day for 5 days. Patients received 60 Gy with BT alone, 45-55 Gy after ERT, and 50-55 Gy after chemotherapy. Local failure was found in 5 cases with T2 lesions. Recurrence occurred in 5 out of 27 cases with tumor thickness of 10 mm or less. On the other hand, there were no recurrences in 7 cases with tumor thickness of more than 10 mm. Among various types of treatment, BT following systemic chemotherapy or AI exhibited better results (local failure: 1/17) than other modalities. Lymph node metastases appeared in 11 cases. Cause specific survival was 91% at 2 years in all cases. Ulcerations of the tongue were noted in 7 in 26 evaluable cases. Although ulceration occurred in 6/13 cases treated until March 1994, the incidence decreased to 1/13 afterwards. Careful implantation and dose prescription contributed to the decrease in ulceration. Ulcerative lesions healed with conservative care within 6 months in all cases. Bone exposure occurred in 2 cases that received 60 Gy following AI for advanced diseases. HDR fractionated brachytherapy may be a workable alternative to LDR therapy for cancer of the tongue. Brachytherapy following chemotherapy can be applied to more advanced cases of the disease. (K.H.)

  13. Conformational episcleral brachytherapy in ocular tumors

    International Nuclear Information System (INIS)

    Brachytherapy with an episcleral plate is an alternative treatment for choroid melanomas and retinoblastomas that allows the sight to be saved. The most common techniques use a metal applicator with beta or Co-60 transmitters, which have a standard geometry, require surgical installation of the active devices and do not allow optimized dosimetry. In 1997, the Clinica Alemana in Santiago, Chile, developed a new device based on the one described by J.P. Gerard (1988), with plastic material, personalized and with delayed charge. Three cases have been treated. Two retinoblastomas: 1) Primary treatment in unilateral Rb, R.E. group II in a 9 month old boy, 2) External post radiotherapy rescue in oculus ultimus by bilateral Rb in a 10 year old girl, and 3) Choroid melanoma T3N0M0 in a 77 year old woman. A personalized applicator was prepared in each case depending on the size and location of the tumor. The distribution of the vector catheters was designed following the Paris system standards. The applicator was inserted in the operating room, under general anesthesia by a team of trained ophthalmologists. An X-ray and helichoidal simulation scan were taken with fictitious sources. Previsional dosimetry was undertaken, with evaluation of the dosage to the tumor apex, crystalline lens, sclera and optic nerve. Prolonged activation with low level dosage Ir-192 wires was performed in a protected room. When the programmed dosage was completed, the sources and then the inactive applicator were removed. Dosage: A 40 Gy dose was applied in the retinoblastoma to the tumor apex and 60 Gy to the melanoma, over a 2 to 3 day period. Tolerance was excellent, there were no incidents or acute complications. The retinoblastomas fully regressed in 1 to 2 weeks, with no local relapse or after affects after 2, 4 and 6 months of follow-up. The 3 patients have retained their sight. The development of this technique is feasible and with enough resources, relatively easy to implement. It has

  14. Severe rectal complications after prostate brachytherapy

    International Nuclear Information System (INIS)

    Purpose: Some investigators have reported severe rectal complications after brachytherapy. Due to the low number of such events, their relationship to dosimetric parameters has not been well characterized. Methods and materials: A total of 3126 patients were treated with low dose rate brachytherapy from 1998 through 2010. 2464 had implant alone, and 313 had implant preceded by 44–46 Gy supplemental external beam radiation (EBRT). Post-implant dosimetry was based on a CT scan obtained on the day of implant, generally within 30 min of the procedure. Every patient’s record was reviewed for occurrence of rectal complications. Results: Eight of 2464 patients (0.32%) treated with brachytherapy alone developed a radiation-related rectal fistula. Average prostatic and rectal dose parameters were moderately higher for fistula patients than for patients without a severe rectal complication. For instance, the average R100 was 1.2 ± 0.75 cc for fistula patients, versus 0.37 ± 0.88 cc for non-fistula patients. However, the fistula patients’ values were well within the range of values for patients without a rectal complication. Four patients had some attempt at repair or reconstruction, but long-term functional outcomes were not favorable. Conclusions: Rectal fistulas are a very uncommon potential complication of prostate brachytherapy, which can occur even in the setting of acceptable day 0 rectal doses. Their occurrence is not easily explained by standard dosimetric or clinical factors

  15. Early voiding dysfunction associated with prostate brachytherapy.

    Science.gov (United States)

    Wagner; Nag; Young; Bahnson

    2000-12-15

    Introduction: Transperineal prostate brachytherapy is gaining popularity as a treatment for clinically localized carcinoma of the prostate. Very little prospective data exists addressing the issue of complications associated with this procedure. We present an analysis of the early voiding dysfunction associated with prostate brachytherapy. Materials and Methods: Forty-six consecutive patients who underwent Palladium-103 (Pd-103) seed placement for clinically localized prostate carcinoma were evaluated prospectively for any morbidity associated with the procedure. Twenty-three patients completed an International Prostate Symptom Score (IPSS) questionnaire preoperatively, at their first postoperative visit, and at their second postoperative visit. The total IPSS, each of the seven individual components, and the "bother" score were evaluated separately for each visit, and statistical significance was determined. Results: Urinary retention occurred in 7/46 patients (15%). Of these, 5 were able to void spontaneously after catheter removal. One patient is maintained with a suprapubic tube, and one patient is currently on continuous intermittent catheterization. Baseline IPSS was 7.1 and this went to 20.0 at the first postoperative visit (p<0.001). By the second postoperative visit, the IPSS was 8.0. Conclusions: In our experience, prostate brachytherapy for localized carcinoma of the prostate is associated with a 15% catheterization rate and a significant increase in the IPSS (7.1 to 20.0). This increase in the IPSS seems to be self-limited. Patients need to be educated on these issues prior to prostate brachytherapy. PMID:11113369

  16. CT-based interstitial HDR brachytherapy

    Energy Technology Data Exchange (ETDEWEB)

    Kolotas, C.; Baltas, D.; Zamboglou, N. [Staedtische Kliniken Offenbach (Germany). Strahlenklinik

    1999-09-01

    Purpose: Development, application and evaluation of a CT-guided implantation technique and a fully CT-based treatment planning procedure for brachytherapy. Methods and Materials: A brachytherapy procedure based on CT-guided implantation technique and CT-based treatment planning has been developed and clinical evaluated. For this purpose a software system (PROMETHEUS) for the 3D reconstruction of brachytherapy catheters and patient anatomy using only CT scans has been developed. An interface for the Nucletron PLATO BPS treatment planning system for optimization and calculation of dose distribution has been devised. The planning target volume(s) are defined as sets of points using contouring tools and are used for optimization of the 3D dose distribution. Dose-volume histogram based analysis of the dose distribution (COIN analysis) enables a clinically realistic evaluation of the brachytherapy application to be made. The CT-guided implantation of catheters and the CT-based treatment planning procedure has been performed for interstitial brachytherapy and for different tumor sites in 197 patients between 1996 and 1997. Results: The accuracy of the CT reconstruction was tested using first a quality assurance phantom and second, a simulated interstitial implant of 12 needles. These were compared with the results of reconstruction using radiographs. Both methods gave comparable results with regard to accuracy, but the CT based reconstruction was faster. Clinical feasibility was proved in pre-irradiated recurrences of brain tumors, in pretreated recurrences or metastatic disease, and in breast carcinomas. The tumor volumes treated were in the range 5.1 to 2,741 cm{sup 3}. Analysis of implant quality showed a slightly significant lower COIN value for the bone implants, but no differences with respect to the planning target volume. Conclusions: The Offenbach system, incorporating the PROMETHEUS software for interstitial HDR brachytherapy has proved to be extremely valuable

  17. In-phantom dosimetric measurements as quality control for brachytherapy. System check and constancy check

    International Nuclear Information System (INIS)

    In brachytherapy dosimetric measurements are difficult due to the inherent dose-inhomogeneities. Typically in routine clinical practice only the nominal dose rate is determined for computer controlled afterloading systems. The region of interest lies close to the source when measuring the spatial dose distribution. In this region small errors in the positioning of the detector, and its finite size, lead to large measurement uncertainties that exacerbate the routine dosimetric control of the system in the clinic. The size of the measurement chamber, its energy dependence, and the directional dependence of the measurement apparatus are the factors which have a significant influence on dosimetry. Although ionisation chambers are relatively large, they are employed since similar chambers are commonly found on clinical brachytherapy units. The dose is determined using DIN 6800 [11] since DIN 6809-2 [12], which deals with dosimetry in brachytherapy, is antiquated and is currently in the process of revision. Further information regarding dosimetry for brachytherapy can be found in textbooks [1] and [2]. The measurements for this work were performed with a HDR (High-Dose-Rate) 192Ir source, type mHDR V2, and a Microselectron Afterloader V2 both from Nucletron/Elekta. In this work two dosimetric procedures are presented which, despite the aforemention difficulties, should assist in performing checks of the proper operation of the system. The first is a system check that measures the dose distribution along a line and is to be performed when first bringing the afterloader into operation, or after significant changes to the system. The other is a dosimetric constancy check, which with little effort can be performed monthly or weekly. It simultaneously verifies the positioning of the source at two positions, the functionality of the system clock and the automatic re-calculation of the source activity.

  18. Subcritical monitoring studies in BZD/2 using alternative absorber compositions and a localised neutron source

    International Nuclear Information System (INIS)

    A series of supplementary subcritical monitoring studies has been carried out in the Single Annular Core BZD/2. The first part concerned the use of alternative absorber compositions: 40 % enriched B4C and Eu2O3. The worth of the 40 % enriched B4C absorber relative to the naturally enriched one was found to be significantly lower than for the corresponding measurements in the conventional core BZB (1.197 versus 1.259). Although an influence of the harder spectrum in BZD is likely, the results of similar studies in BZC seem to contradict this assumption. Within the experimental errors, the worth of the Eu2O3 absorber relative to natural B4C agrees with that found in BZB. As in previous investigations, diffusion theory calculations were found to overestimate the worth of the 40 % enriched B4C absorber relative to the natural one by several percent. The worth of Eu2O3 relative to B4C-nat was again severely underpredicted. In a second series of experiments, a localised neutron source (Cf-252) was introduced into the core. For the two absorber arrays established in the presence of the source, the MSM analysis produced reactivities, which agree within about 0.5 % relative with those, obtained from previous measurements of these arrays without the localised source. This confirms the satisfactory performance of the MSM technique even in a strongly decoupled annular system with very irregular source distribution

  19. Computational Program of Isodose and TPS of 125I Seed for Brachytherapy

    International Nuclear Information System (INIS)

    Radioactive sources are widely used in several fields including for medical purposes. One use of radioactive sources in medical field is radiotherapy to cure the cancerous organs. Brachytherapy term is the radiotherapy where the radiation source is placed inside or as close as possible to the cancer needing treatment. In order to support the domestic application of 125I seeds in brachytherapy, a computational program for isodose and TPS (Treatment Planning System) calculation shall be available. The preparation of the such program has been successfully developed using Microsoft Visual Basic for Windows and its supporting tools. This program can display the two-dimensions-isodose contour of 1-20 125I seeds presented in direction of lateral, anterior (AP) and caodal. The dose rate at the distances of 1, 2, 3 and 4 cm from the center point assumed as (0,0) can also be calculated from 1 to 360 days after implantation of the 125I seeds. The entered data as well as the resulting calculation and the contour presentation can be saved and be quickly traced and redisplayed at any time necessarily. This computer program is hopefully able to assist physicians in the implementation of 125I seeds implantation for brachytherapy. (author)

  20. Langzeitergebnisse bei Aderhautmelanom nach 106Ruthenium-Brachytherapie

    OpenAIRE

    Krause, Nona

    2015-01-01

    Introduction: 106Ruthenium-brachytherapy (106Ru-brachytherapy) is an established therapy for small and medium-sized uveal melanomas. The aim of this study was to examine the long-time results in regard to recurrence rate, complication rate, ocular preservation, metastasis rate and survival with malignant uveal and ciliary body melanoma, as well as relevant prognosis factors, subsequent to 106Ru-brachytherapy. Methodology: In this retrospective study of all cases with uveal or with ciliary ...

  1. Prostate cancer brachytherapy; Braquiterapia de cancer de prostata

    Energy Technology Data Exchange (ETDEWEB)

    Abreu, Carlos Eduardo Vita; Silva, Joao L. F. [Hospital Sirio Libanes, Sao Paulo, SP (Brazil). Centro de Oncologia. Dep. de Radioterapia; Srougi, Miguel; Nesrallah, Adriano [Universidade Federal de Sao Paulo (UNIFESP), SP (Brazil). Escola Paulista de Medicina (EPM). Disciplina de Urologia]. E-mail: cevitabr@mandic.com.br

    1999-07-01

    The transperineal brachytherapy with {sup 125}I/Pd{sup 103} seed implantation guided by transurethral ultrasound must be presented as therapeutical option of low urinary morbidity in patients with localized prostate cancer. The combined clinical staging - including Gleason and initial PSA - must be encouraged, for definition of a group of low risk and indication of exclusive brachytherapy. Random prospective studies are necessary in order to define the best role of brachytherapy, surgery and external beam radiation therapy.

  2. Low dose rate Ir-192 interstitial brachytherapy for prostate cancer

    Energy Technology Data Exchange (ETDEWEB)

    Oki, Yosuke; Dokiya, Takushi; Yorozu, Atsunori; Suzuki, Takayuki; Saito, Shiro; Monma, Tetsuo; Ohki, Takahiro [National Tokyo Medical Center (Japan); Murai, Masaru; Kubo, Atsushi

    2000-04-01

    From December 1997 through January 1999, fifteen prostatic cancer patients were treated with low dose rate Ir-192 interstitial brachytherapy using TRUS and perineal template guidance without external radiotherapy. Up to now, as no apparent side effects were found, the safety of this treatment is suggested. In the future, in order to treat prostatic cancer patients with interstitial brachytherapy using I-125 or Pd-103, more investigation for this low dose rate Ir-192 interstitial brachytherapy is needed. (author)

  3. Ocular brachytherapy dosimetry for 103Pd and 125I in the presence of gold nanoparticles: a Monte Carlo study.

    Science.gov (United States)

    Asadi, Somayeh; Vaez-Zadeh, Mehdi; Vahidian, Mohammad; Marghchouei, Mahdieh; Masoudi, S Farhad

    2016-01-01

    The aim of the present Monte Carlo study is to evaluate the variation of energy deposition in healthy tissues in the human eye which is irradiated by brachytherapy sources in comparison with the resultant dose increase in the gold nanoparticle (GNP)-loaded choroidal melanoma. The effects of these nanoparticles on normal tissues are compared between 103Pd and 125I as two ophthalmic brachytherapy sources. Dose distribution in the tumor and healthy tissues has been taken into account for both brachytherapy sources. Also, in certain points of the eye, the ratio of the absorbed dose by the normal tissue in the presence of GNPs to the absorbed dose by the same point in the absence of GNPs has been calculated. In addition, differences of the absorbed dose in the tumor observed in the comparison of simple water phantom and actual simulated human eye in presence of GNPs are also a matter of interest that have been considered in the present work. The difference between the eye globe and the water phantom is more obvious for 125I than that of the 103Pd when the ophthalmic dosimetry is done in the presence of GNPs. Whenever these nanoparticles are utilized in enhancing the absorbed dose by the tumor, the use of 125I brachytherapy source will greatly amplify the amount of dose enhancement factor (DEF) in the tumor site without inflicting much dam-age to healthy organs, when compared to the 103Pd source. For instance, in the concentration of 30 mg GNPs, the difference amongst the calculated DEF for 125I between these phantoms is 5.3%, while it is 2.45% for 103Pd. Furthermore, in Monte Carlo studies of eye brachytherapy, more precise definition of the eye phantom instead of a water phantom will become increasingly important when we use 125I as opposed to 103Pd. PMID:27167265

  4. Verification of the calculation program for brachytherapy planning system of high dose rate (PLATO); Programa de verificacion del calculo para un sistema de planificacion de braquiterapia de alta tasa de dosis (PLATO)

    Energy Technology Data Exchange (ETDEWEB)

    Almansa, J.; Alaman, C.; Perez-Alija, J.; Herrero, C.; Real, R. del; Ososrio, J. L.

    2011-07-01

    In our treatments are performed brachytherapy high dose rate since 2007. The procedures performed include gynecological intracavitary treatment and interstitial. The treatments are performed with a source of Ir-192 activity between 5 and 10 Ci such that small variations in treatment times can cause damage to the patient. In addition the Royal Decree 1566/1998 on Quality Criteria in radiotherapy establishes the need to verify the monitor units or treatment time in radiotherapy and brachytherapy. All this justifies the existence of a redundant system for brachytherapy dose calculation that can reveal any abnormality is present.

  5. Brachytherapy in the treatment of genitourinary rhabdomyosarcoma in children

    International Nuclear Information System (INIS)

    Brachytherapy has been widely used at the Institut Gustave Roussy since 1972 in pediatric oncology. In genitourinary rhabdomyosarcoma, because of its ballistic and physical characteristics, it represents the optimal treatment whenever irradiation is required and brachytherapy feasible. Between 1976 and 1998, 23 children with bladder or prostate rhabdomyosarcoma were treated with a protocol including brachytherapy, with five of them treated with a salvage brachytherapy. All but one brachytherapy was performed during the surgery. Among the 18 brachy-therapies performed as a first-line treatment, eight presented a tumoral evolution: five presented a local evolution, one a local and nodal evolution and two a nodal evolution. Brachytherapy allowed a conservative treatment among ten out of 11 children alive with no evidence of disease. Among the five patients with salvage brachytherapy, two presented a second recurrence. Sequelae were minimal, consisting of one grade I rectitis and one asymptomatic vesical and ureteral reflux. These results are consistent with the published data using more radical treatment. Brachytherapy can represent an alternative to radical surgery, when indications are clearly defined in bladder or prostate rhabdomyosarcoma. This type of treatment can be performed only integrated with other treatments, more particularly with surgery. This approach requires a close cooperation between the different specialists: pediatricians, surgeons and brachy-therapists. (authors)

  6. Implementation of High Dose Rate Brachytherapy in Limited Resource Settings

    International Nuclear Information System (INIS)

    Brachytherapy is an essential component of the curative treatment of cervical cancer, a disease with high incidence in many developing countries The IAEA supports the use of high dose rate brachytherapy for centres with a large number of patients with this disease. HDR brachytherapy is also used in other common cancers such as breast cancer, lung, oesophagus and prostate. This publication provides guidance to radiation oncologists, medical physicists and planners on establishing and operating a high dose rate brachytherapy unit with modern standards and presents the main issues to be addressed for its effective and safe operation

  7. Cost effective method of manual afterloading 192Ir brachytherapy

    International Nuclear Information System (INIS)

    Full text: In radiotherapy, brachytherapy mode of treatment has equal importance like the external beam radiotherapy. In our hospital we have manual afterloading 137Cs kit supplied by BRIT for intracavitary treatment of carcinoma cervix and vaginal cases. In July 1999, we also started afterloading 192Ir brachytherapy. For a hospital like ours, where funds are minimal, it is impossible to procure remote afterloading brachytherapy unit, which is very costly. So we have developed the cost-effective 192Ir manual brachytherapy and so far we have done 60 cases which include intraluminal and interstitial cases

  8. Importance of the elemental composition in brachytherapy with neutrons

    International Nuclear Information System (INIS)

    An analysis is presented of as the small differences that exist in the elementary composition of the wicked tumors, healthy fabrics and some material substitutes of fabric employees in dosimetry, they generate variations in the value of the kerma coefficient and consequently in the absorbed dose of neutrons in the interval 11 eV to 29 MeV. These differences make that the coefficient of kerma of neutrons average for the considered wicked tumors, be between 6% and 7% smaller that the coefficient of kerma of neutrons average for soft fabric, in the interval of interest in therapy with quick neutrons. These results have a special importance during the process of planning of brachytherapy treatments with sources of 252 Cf, to optimize and to individualize the treatments to the patients. (Author)

  9. Design and implementation of an intravascular brachytherapy installation in cardiology

    International Nuclear Information System (INIS)

    Intravascular Brachytherapy (IVB) is a very promising technique for reducing restenosis rates. However, neither the exact absolute dose needed nor the optimal spatial and temporal distribution of dose inside the vessel wall for a successful treatment, nor the physical dosimetry of the various radioactive sources and devices for dose delivery, are well known. In this paper, an overview will be given of the design strategy, the dosimetric and radiation protection-related problems that we have met during the implementation of this technique at San Carlos hospital, adopted or foreseen solutions, and future research fields that we intend to carry out in order to reduce uncertainties and to achieve a deeper knowledge of the parameters that have an influence on the treatment. (author)

  10. Poster — Thur Eve — 40: Automated Quality Assurance for Remote-Afterloading High Dose Rate Brachytherapy

    International Nuclear Information System (INIS)

    High dose rate (HDR) remote afterloading brachytherapy involves sending a small, high-activity radioactive source attached to a cable to different positions within a hollow applicator implanted in the patient. It is critical that the source position within the applicator and the dwell time of the source are accurate. Daily quality assurance (QA) tests of the positional and dwell time accuracy are essential to ensure that the accuracy of the remote afterloader is not compromised prior to patient treatment. Our centre has developed an automated, video-based QA system for HDR brachytherapy that is dramatically superior to existing diode or film QA solutions in terms of cost, objectivity, positional accuracy, with additional functionalities such as being able to determine source dwell time and transit time of the source. In our system, a video is taken of the brachytherapy source as it is sent out through a position check ruler, with the source visible through a clear window. Using a proprietary image analysis algorithm, the source position is determined with respect to time as it moves to different positions along the check ruler. The total material cost of the video-based system was under $20, consisting of a commercial webcam and adjustable stand. The accuracy of the position measurement is ±0.2 mm, and the time resolution is 30 msec. Additionally, our system is capable of robustly verifying the source transit time and velocity (a test required by the AAPM and CPQR recommendations), which is currently difficult to perform accurately

  11. Poster — Thur Eve — 40: Automated Quality Assurance for Remote-Afterloading High Dose Rate Brachytherapy

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Anthony; Ravi, Ananth [Sunnybrook Health Sciences Centre/Odette Cancer Centre (Canada)

    2014-08-15

    High dose rate (HDR) remote afterloading brachytherapy involves sending a small, high-activity radioactive source attached to a cable to different positions within a hollow applicator implanted in the patient. It is critical that the source position within the applicator and the dwell time of the source are accurate. Daily quality assurance (QA) tests of the positional and dwell time accuracy are essential to ensure that the accuracy of the remote afterloader is not compromised prior to patient treatment. Our centre has developed an automated, video-based QA system for HDR brachytherapy that is dramatically superior to existing diode or film QA solutions in terms of cost, objectivity, positional accuracy, with additional functionalities such as being able to determine source dwell time and transit time of the source. In our system, a video is taken of the brachytherapy source as it is sent out through a position check ruler, with the source visible through a clear window. Using a proprietary image analysis algorithm, the source position is determined with respect to time as it moves to different positions along the check ruler. The total material cost of the video-based system was under $20, consisting of a commercial webcam and adjustable stand. The accuracy of the position measurement is ±0.2 mm, and the time resolution is 30 msec. Additionally, our system is capable of robustly verifying the source transit time and velocity (a test required by the AAPM and CPQR recommendations), which is currently difficult to perform accurately.

  12. A comparison of complications between ultrasound-guided prostate brachytherapy and open prostate brachytherapy

    International Nuclear Information System (INIS)

    Purpose: Prostate brachytherapy has reemerged during the 1990s as a treatment for clinically localized prostate cancer. The renewed popularity of prostate brachytherapy is largely due to the use of transrectal ultrasound of the prostate, which allows for more accurate isotope placement within the prostate when compared to the open approach. The present study investigates whether this improved cancer control is at the expense of increased morbidity by comparing the morbidity after transrectal ultrasound-guided prostate brachytherapy to the morbidity after prostate brachytherapy performed via an open approach. Methods and Materials: All men in the Medicare population who underwent prostate brachytherapy in the year 1991 were identified. These men were further stratified into those men who underwent prostate brachytherapy via an open approach and the men who underwent prostate brachytherapy with ultrasound guidance. All subsequent inpatient, outpatient, and physician (Part B) Medicare claims for these men from the years 1991-1993 were then analyzed to determine outcomes. Results: In the year 1991, 2124 men in the Medicare population underwent prostate brachytherapy. An open approach was used in 715 men (33.7%), and ultrasound guidance was used in 1409 men (66.3%). Mean age for both cohorts was 73.7 years with a range of 50.7-92.8 years for the ultrasound group and 60.6-92.1 years for the open group. A surgical procedure for the relief of bladder outlet obstruction was performed in 122 men (8.6%) in the ultrasound group and in 54 men (7.6%) in the open group. An artificial urinary sphincter was placed in 2 men (0.14%) in the ultrasound group and in 2 men (0.28%) in the open group. A penile prosthesis was implanted in 10 men (0.71%) in the ultrasound group and in 4 men (0.56%) in the open group. A diagnosis code for urinary incontinence was carried by 95 men (6.7%) in the ultrasound group and by 45 men (6.3%) in the open group. A diagnosis code for erectile dysfunction

  13. CT use for nasopharingeal molds realization in endocavitary brachytherapy

    International Nuclear Information System (INIS)

    Purpose: We present the following procedure for the making of individual molds with dental silicone for endocavitary brachytherapy of nasopharingeal cancer aided by CT scan. Procedure: Head immobilization during the realization of nasopharynx CT. Planification of treatment using these CT images, to determine the optimum position of radioactive sources. Printing on paper CT images with the nasopharynx contoured walls and the radioactive sources position. Realization of the mold in plastiline with the aid of the cuts of printer paper cut out with the nasopharynx form. Obtaining of the negative of the mold of plastiline by means of the use of alginate. Placement of two number 20 rectal rigid catheters with metal malleable bars inside them, in order to give them an adequate form in relation to the previous carried out planning. Filling in of alginato negative, where rectal catheters were placed, with Provil MCD Bayer Dental, a silicone based material for precision impression. We recommend to crossing the catheters' end with a number 2 silk thread to secure the catheter. An end of the silk thread is left outside the mold in order to help the extraction at the end of application. We advise to carry out a neuroleptic anaesthesia for its insertion, for the purpose of achieving a soft palate suitable relaxation. It makes the insertion easier. Repeat CT with the mold and phantoms in position to know a definitive dose distribution calculation. Conclusion: This method avoids the necessity of general anaesthesia in the realization of individual molds of nasopharyx for endocavitary brachytherapy and it improves the implant dosimetry

  14. Measurement and Simulation of Neutron response at Cf-252 neutron field using SiC Diode Detector

    International Nuclear Information System (INIS)

    Recently, a silicon carbide (SiC) semiconductor detector is drawing attention as a neutron detector in the harsh environment because of its discriminative characteristics. SiC is very resistant to high temperature and intense radiation field, compared with the other semiconductor materials. In this sense, SiC is expected to be a semiconductor material well suited for nuclear power plant applications such as in-core reactor neutron flux monitoring and safeguarding nuclear materials. The SiC diode detector could be expected to replace the SPND. In our previous study, several types of 4H SiC p-i-n diode detector were fabricated and tested. This study is focused on the prediction of neutron response for SiC diode detector before in-core experiment

  15. CT-guided brachytherapy. A novel percutaneous technique for interstitial ablation of liver malignancies; CT-gesteuerte Brachytherapie. Eine neue perkutane Technik zur interstitiellen Ablation von Lebermetastasen

    Energy Technology Data Exchange (ETDEWEB)

    Ricke, J.; Wust, P.; Stohlmann, A.; Beck, A.; Cho, C.H.; Pech, M.; Wieners, G.; Spors, B.; Werk, M.; Rosner, C.; Haenninen, E.L.; Felix, R. [Klinik fuer Strahlenheilkunde, Charite Virchow-Klinikum, Humboldt-Univ. zu Berlin (Germany)

    2004-05-01

    Purpose: to assess safety and efficacy of CT-guided brachytherapy of liver malignancies. Patients and methods: 21 patients with 21 liver malignancies (19 metastases, two primary liver tumors) were treated with interstitial CT-guided brachytherapy applying a {sup 192}Ir source. In all patients, the use of image-guided thermal tumor ablation such as by radiofrequency or laser-induced thermotherapy (LITT) was impeded either by tumor size {>=} 5 cm in seven, adjacent portal or hepatic vein in ten, or adjacent bile duct bifurcation in four patients. Dosimetry was performed using three-dimensional CT data sets acquired after CT-guided positioning of the brachytherapy catheters. Results: the mean tumor diameter was 4.6 cm (2.5-11 cm). The mean minimal tumor dose inside the tumor margin amounted to 17 Gy (12-20 Gy). The proportion of the liver parenchyma exposed to > 5 gy was 18% (5-39%) of total liver parenchyma minus tumor volume. Nausea and vomiting were observed in six patients after brachytherapy (28%). One patient demonstrated obstructive jaundice due to tumor edema after irradiation of a metastasis adjacent to the bile duct bifurcation. We commonly encountered asymptomatic increases of liver enzymes. Local control rates after 6 and 12 months were 87% and 70%, respectively. Conclusion: CT-guided brachytherapy is safe and effective. This technique displays broader indications compared to image-guided thermal ablation by radiofrequency or LITT with respect to tumor size or localization. (orig.) [German] Ziel: Analyse der Sicherheit und Effektivitaet CT-gesteuerter Brachytherapie zur Ablation von Lebermalignomen. Patienten und Methodik: 21 Patienten mit 21 Lebermalignomen (19 Metastasen, zwei primaere Lebermalignome) wurden mit perkutaner, CT-gesteuerter interstitieller Brachytherapie mit {sup 192}Ir behandelt. Alle Patienten wiesen Umstaende auf, die eine bildgefuehrte thermische Ablation mit Radiofrequenz oder laserinduzierter Thermotherapie (LITT) einschraenkten

  16. Plastic optical fibre sensor for in-vivo radiation monitoring during brachytherapy

    Science.gov (United States)

    Woulfe, P.; Sullivan, F. J.; Lewis, E.; O'Keeffe, S.

    2015-09-01

    An optical fibre sensor is presented for applications in real-time in-vivo monitoring of the radiation dose a cancer patient receives during seed implantation in Brachytherapy. The sensor is based on radioluminescence whereby radiation sensitive scintillation material is embedded in the core of a 1mm plastic optical fibre. Three scintillation materials are investigated: thallium-doped caesium iodide (CsI:Tl), terbium-doped gadolinium oxysulphide (Gd2O2S:Tb) and europium-doped lanthanum oxysulphide (La2O2S:Eu). Terbium-doped gadolinium oxysulphide was identified as being the most suitable scintillator and further testing demonstrates its measureable response to different activities of Iodine-125, the radio-active source commonly used in Brachytherapy for treating prostate cancer.

  17. Australasian brachytherapy audit: results of 'end-to-end' dosimetry pilot study

    International Nuclear Information System (INIS)

    We present the results of a pilot study to test the feasibility of a brachytherapy dosimetry audit. The feasibility study was conducted at seven sites from four Australian states in both public and private centres. A purpose-built cylindrical water phantom was imaged using the local imaging protocol and a treatment plan was generated to deliver 1Gy to the central (1 of 3) thermoluminescent dosimeter (TLD) from six dwell positions. All centres completed the audit, consisting of three consecutive irradiations, within a 2-h time period, with the exception of one centre that uses a pulsed dose rate brachytherapy unit. All TLD results were within 4.5% of the predicted value, with the exception of one subset where the dwell position step size was incorrectly applied. While the limited data collected in the study demonstrated considerable heterogeneity in clinical practice, the study proved a brachytherapy dosimetry audit to be feasible. Future studies should include verification of source strength using a Standard Dosimetry Laboratory calibrated chamber, a phantom that more closely mimics the clinical situation, a more comprehensive review of safety and quality assurance (QA) procedures including source dwell time and position accuracy, and a review of patient treatment QA procedures such as applicator position verification.

  18. Evaluation of Brachytherapy Facility Shielding Status in Korea Obtained From Radiation Safety Reports

    International Nuclear Information System (INIS)

    Thirty-eight radiation safety reports for brachytherapy equipment were evaluated to determine the current status of brachytherapy units in Korea and to assess how radiation oncology departments in Korea complete radiation safety reports. The following data was collected: radiation safety report publication year, brachytherapy unit manufacturer, type and activity of the source that was used, affiliation of the drafter, exposure rate constant, the treatment time used to calculate workload and the HVL values used to calculate shielding design goal values. A significant number of the reports (47.4%) included the personal information of the drafter. The treatment time estimates varied widely from 12 to 2,400 min/week. There was acceptable variation in the exposure rate constant values (ranging between 0.469 and 0.592 (R·m2/Ci·hr), as well as in the HVLs of concrete, steel and lead for Iridium-192 sources that were used to calculate shielding design goal values. There is a need for standard guidelines for completing radiation safety reports that realistically reflect the current clinical situation of radiation oncology departments in Korea. The present study may be useful for formulating these guidelines

  19. Aspects of the application of complementary brachytherapy for early invasive breast cancer

    International Nuclear Information System (INIS)

    Initial studies of brachytherapy with the 'Mammosite Radiation Therapy System', a device consisted by a catheter centered inside a inflate balloon, to perform breast brachytherapy was revised. A high activity source was applied into the balloon, exposing to the tumor bed to a high absorbed dose, while the surrounding areas receives one reduced by to a factor 1/r2, during a short interval of time. The high acute dose provides a booster to conventional radiation therapy, resulting in a better local control. The acceptable esthetic impact achieved and an easier device setting stimulated the present dosimetric study. The brachytherapy with Ir192 was simulated through the development of a computerized digital voxels phantom, which represented the breast anatomy. The Monte Carlo Code (MCNP TM, 1977) was used to evaluate the radiation of the tumor bed and health tissues. Results from simulations shows, as example, an amount of radiation absorbed by the tumor bed of 11.30 Gy up to 5 mm around the balloon surface. Radiation selectivity is also shown, in which tumour bed absorbed more radiation than the surrounding tissues, whose maximum values were: skin (6.73 Gy), muscle (7.69 Gy), and lung (3.02 Gy), for a fifteen-minute exposure of a Ir-152 source. The simulation results are presented. Reliability of this radiotherapy technique as a postoperative booster in early breast cancer is presented and confirmed in this work. (author)

  20. Radiation risk to patient and intervention personell from intracoronary brachytherapy; Die Dosisbelastung von Patienten und Interventionspersonal in der intravaskulaeren Brachytherapie

    Energy Technology Data Exchange (ETDEWEB)

    Hefner, A. [Austrian Research Centers Seibersdorf (Austria); Kirisits, C.; Georg, D.; Poetter, R. [Universitaetsklinik fuer Strahlentherapie und Strahlenbiologie, Wien (Austria); Aiginger, H. [Atominstitut der Oesterreichischen Universitaeten, Wien (Austria)

    2001-07-01

    During the last years coronary brachytherapy has been extensively explored as a new treatment to prevent restenosis after percutaneous coronary interventions. While clinical and physical aspects of such treatments are addressed in literature, there is little information available on radiation protection and radiation safety aspects. In this paper we estimate the radiation risk for the patient using analytical methods and Monte Carlo calculations for three delivering systems currently used in clinics. Additionally, radiation risk to personell involved in such treatments is investigated. For gamma emitting sources the radiation exposure to patients is in the order of magnitude of the exposure due to diagnostic angiography. Doses to organs at risk when applying beta emitting sources are significantly lower. Measured doses for intervention personell are consistent with the estimated whole body dose. They are smaller than 7,5 {mu} {mu}Sv per intervention, which is a dose much less than 0,1 permille of the annual radiation workers maximum permissible dose (MPD) recommended by EC regulations. (orig.) [German] Intrakoronaere Brachytherapie ist in den letzten Jahren zu einer vielversprechenden Methode der Strahlenbehandlung geworden, um die Rate an Wiederverschluessen von Gefaessen nach revaskularisierenden Eingriffen zu verringern. Waehrend ueber die klinischen Behandlungsmethoden ausreichend Literatur vorhanden ist, stehen auf dem Gebiete des Strahlenschutzes fast keine Veroeffentlichungen zur Verfuegung. In dieser Veroeffentlichung gehen wir insbesondere auf die Abschaetzung des Strahlenrisikos des Patienten durch analytische Methoden und Monte Carlo-Rechnung fuer die drei derzeit in den Kliniken verwendeten Systeme ein. Ausserdem geben wir eine Abschaetzung des Strahlenrisikos des mit der Behandlung betrauten Personals. Die Strahlenbelastung des Patienten mit Systemen mit Gammastrahlern lieht in der Groessenordnung der Dosisbelastung bei der diagnostischen Angiographie

  1. The Preliminary Prototype of Medium Dose Rate Brachytherapy Equipment

    Directory of Open Access Journals (Sweden)

    A. Satmoko

    2013-08-01

    Full Text Available A preliminary prototype of a brachytherapy equipment has been constructed. The work started by developing conceptual design, followed by basic design and detailed design. In the conceptual design, design requirements are stated. In the basic design, technical specifications for main components are determined. In detailed design, general drawings are discussed. The prototype consists of three main systems: a mechanical system, an instrumentation system, and a safety system. The mechanical system assures the movement mechanism of the isotope source position beginning from the standby position until the applicators. It consists of three main modules: a position handling module, a container module, and a channel distribution module. The position handling module serves to move the isotope source position. As shielding, the second module is to store the source when the equipment is in standby position. The prototype provides 12 output channels. The channel selection is performed by the third module. The instrumentation system controls the movement of source position by handling motor operations. It consists of several modules. A microcontroller module serves as a control center whose task includes both controlling motors and communicating with computer. A motor module serves to handle motors. 10 sensors, including their signal conditionings, are introduced to read the environment conditions of the equipment. LEDs are used to display these conditions. In order to facilitate the operators’ duty, communication via RS232 is provided. The brachytherapy equipment can therefore be operated by using computer. Interface software is developed using C# language. To complete both mechanical and instrumentation systems performance, a safety system is developed to make sure that the safety for operator and patients from receiving excessive radiation. An interlock system is introduced to guard against abnormal conditions. In the worst case, a manual intervention

  2. Review of clinical brachytherapy uncertainties: Analysis guidelines of GEC-ESTRO and the AAPM

    International Nuclear Information System (INIS)

    Background and purpose: A substantial reduction of uncertainties in clinical brachytherapy should result in improved outcome in terms of increased local control and reduced side effects. Types of uncertainties have to be identified, grouped, and quantified. Methods: A detailed literature review was performed to identify uncertainty components and their relative importance to the combined overall uncertainty. Results: Very few components (e.g., source strength and afterloader timer) are independent of clinical disease site and location of administered dose. While the influence of medium on dose calculation can be substantial for low energy sources or non-deeply seated implants, the influence of medium is of minor importance for high-energy sources in the pelvic region. The level of uncertainties due to target, organ, applicator, and/or source movement in relation to the geometry assumed for treatment planning is highly dependent on fractionation and the level of image guided adaptive treatment. Most studies to date report the results in a manner that allows no direct reproduction and further comparison with other studies. Often, no distinction is made between variations, uncertainties, and errors or mistakes. The literature review facilitated the drafting of recommendations for uniform uncertainty reporting in clinical BT, which are also provided. The recommended comprehensive uncertainty investigations are key to obtain a general impression of uncertainties, and may help to identify elements of the brachytherapy treatment process that need improvement in terms of diminishing their dosimetric uncertainties. It is recommended to present data on the analyzed parameters (distance shifts, volume changes, source or applicator position, etc.), and also their influence on absorbed dose for clinically-relevant dose parameters (e.g., target parameters such as D90 or OAR doses). Publications on brachytherapy should include a statement of total dose uncertainty for the entire

  3. Sexual function after permanent prostate brachytherapy

    International Nuclear Information System (INIS)

    Purpose: To determine the incidence of potency preservation following permanent prostate brachytherapy and to evaluate the effect of multiple clinical and treatment parameters on penile erectile function. Materials and Methods: 425 patients underwent permanent prostate brachytherapy from April 1995 to October 1999. 209 patients who were potent prior to brachytherapy and currently not receiving hormonal manipulation were mailed an International Index of Erectile Function (IIEF) questionnaire with a pre-addressed stamped envelope. 180 patients completed and returned the questionnaire. Median patient follow-up was 39 months (range 18-74 months). Pre-implant erectile function was assigned using a three-tiered scoring system (2 = erections always or nearly always sufficient for vaginal penetration; 1 = erections sufficient for vaginal penetration but considered suboptimal; 0 = the inability to obtain erections and/or erections inadequate for vaginal penetration). Post-implant potency was defined as an IIEF score >11. Clinical parameters evaluated for sexual function included patient age, clinical T stage, elapsed time since implantation, hypertension, diabetes mellitus, and tobacco consumption. Evaluated treatment parameters included the utilization of neoadjuvant hormonal manipulation and the choice of isotope. The efficacy of sildenafil citrate in brachytherapy induced erectile dysfunction (ED) was also evaluated. Results: A pre-treatment erectile function score of 2 and 1 were assigned to 126 and 54 patients respectively. With 6 year follow up, 39% of patients maintained potency following prostate brachytherapy with a plateau on the curve. Post-implant preservation of potency (IIEF>11) correlated with pre-implant erectile function (50% versus 14% for pre-implant scores of 2 and 1 respectively, p≤0.0001), patient age (56%, 38%, and 23% for patients <60 years of age, 60-69 years of age, and ≥70 years of age respectively, p=0.012) and a history of diabetes mellitus

  4. Brachytherapy in treatment of vaginal cancer

    OpenAIRE

    A. D. Kaprin; V. N. Galkin; S. A. Ivanov; V. A. Solodkiy; V. A. Titova

    2016-01-01

    Characteristics of diagnosis and treatment of different types of primary vaginal cancer are highlighted, the role and place of brachytherapy as independent method or combined treatment modality for this pathology is shown in the review. Epidemiological data on incidence of vaginal cancer in Russia are represented, presumptive mechanisms for development of the disease, risk factors, histological types, features of the course, clinical presentation, diagnostic algorithm are described. Treatment...

  5. Photoacoustic imaging of prostate brachytherapy seeds

    OpenAIRE

    Su, Jimmy L.; Bouchard, Richard R.; Karpiouk, Andrei B.; Hazle, John D.; Emelianov, Stanislav Y.

    2011-01-01

    Brachytherapy seed therapy is an increasingly common way to treat prostate cancer through localized radiation. The current standard of care relies on transrectal ultrasound (TRUS) for imaging guidance during the seed placement procedure. As visualization of individual metallic seeds tends to be difficult or inaccurate under TRUS guidance, guide needles are generally tracked to infer seed placement. In an effort to improve seed visualization and placement accuracy, the use of photoacoustic (PA...

  6. Erectile Function Durability Following Permanent Prostate Brachytherapy

    International Nuclear Information System (INIS)

    Purpose: To evaluate long-term changes in erectile function following prostate brachytherapy. Methods and Materials: This study included 226 patients with prostate cancer and preimplant erectile function assessed by the International Index of Erectile Function-6 (IIEF-6) who underwent brachytherapy in two prospective randomized trials between February 2001 and January 2003. Median follow-up was 6.4 years. Pre- and postbrachytherapy potency was defined as IIEF-6 ≥ 13 without pharmacologic or mechanical support. The relationship among clinical, treatment, and dosimetric parameters and erectile function was examined. Results: The 7-year actuarial rate of potency preservation was 55.6% with median postimplant IIEF of 22 in potent patients. Potent patients were statistically younger (p = 0.014), had a higher preimplant IIEF (p < 0.001), were less likely to be diabetic (p = 0.002), and were more likely to report nocturnal erections (p = 0.008). Potency preservation in men with baseline IIEF scores of 29-30, 24-28, 18-23, and 13-17 were 75.5% vs. 73.6%, 51.7% vs. 44.8%, 48.0% vs. 40.0%, and 23.5% vs. 23.5% in 2004 vs. 2008. In multivariate Cox regression analysis, preimplant IIEF, hypertension, diabetes, prostate size, and brachytherapy dose to proximal penis strongly predicted for potency preservation. Impact of proximal penile dose was most pronounced for men with IIEF of 18-23 and aged 60-69. A significant minority of men who developed postimplant impotence ultimately regained erectile function. Conclusion: Potency preservation and median IIEF scores following brachytherapy are durable. Thoughtful dose sparing of proximal penile structures and early penile rehabilitation may further improve these results.

  7. Preparation and deployment of indigenous 125I-seeds for the treatment of prostate cancer. Dawn of prostate brachytherapy in India

    International Nuclear Information System (INIS)

    'Permanent seed implantation' using 125I- seeds has emerged as an effective treatment modality for management of prostate cancer. An indigenous technology for the production of 125I brachytherapy sources ('BARC 125I Ocu-Prosta seed') has been developed. In this current work, we describe an overview of our experience on large scale production of 125I brachytherapy sources, their quality assessment, in vivo bio-evaluation and initial experience on their journey from bench to bed-side for the treatment of prostate cancer. (author)

  8. Current status of high dose rate brachytherapy in cervical cancer in Korea and optimal treatment schedule

    Energy Technology Data Exchange (ETDEWEB)

    Huh, Seung Jae [College of Medicine, Sungkyunkwan Univ., Seoul (Korea, Republic of)

    1998-12-01

    Brachytherapy is an essential part of radiotherapy for uterine cervical cancer. The low dose rate (LDR) regimen has been the major technique of intracavitary therapy for cervical cancer. However, there has been an expansion in the last 20 years of high dose rate (HDR) machines using Ir-192 sources. Since 1979, HDR brachytherapy has been used for the treatment of uterine cervical cancer in Korea. The number of institutions employing HDR has been increasing, while the number of low dose rate system has been constant. In 1995, there was a total 27 HDR brachytherapy units installed and 1258 cases of patients with cervical cancer were treated with HDR. Most common regimens of HDR brachytherapy are total dose of 30-39 Gy at point A with 10-13 fractions in three fractions per week, 24-32 Gy with 6-8 fractions in two fractions per week, and 30-35 Gy with 6-7 fractions in two fractions per week. The average fractionation regimen of HDR brachytherapy is about 8 fractions of 4. 1 Gy each to point A. In Korea, treatment results for HDR brachytherapy are comparable with the LDR series and appears to be a safe and effective alternative to LDR therapy for the treatment of cervical carcinoma. Studies from the major centers report the five-year survival rate of cervical cancer as, 78-86% for Stage I, 68-85% for stage II, and 38-56% for Stage III. World-wide questionnaire study and Japanese questionnaire survey of multiple institutions showed no survival difference in any stages and dose-rate effect ratio (HDR/LDR) was calculated to be 0.54 to 0.58. However, the optimum treatment doses and fractionation schemes appropriate to generate clinical results comparable to conventional LDR schemes have yet to be standardized. In conclusion, HDR intracavitary radiotherapy is increasingly practiced in Korea and an effective treatment modality for cervical cancer. To determine the optimum radiotherapy dose and fractionation schedule, a nation-wide prospective study is necessary in Korea. In

  9. Dose effect of guidewire position in intravascular brachytherapy

    International Nuclear Information System (INIS)

    It has been reported that the dose effects of metallic guidewires are significant in intravascular brachytherapy (IVBT) using a beta source. The purpose of this work is to investigate the dependence of these dose effects on guidewire position. The EGS4 Monte Carlo codes were used to perform the dose calculations for the 90Sr (NOVOSTE), 32P (Guidant) and 192Ir (BEST Ind.) sources with and without a guidewire in place. Guidewires were placed at various distances from the central axes of the sources. Due to the attenuation by the guidewires, a dose reduction of up to 70% behind a guidewire was observed for the beta sources, while the dose perturbation was found to be negligible for the gamma source. The dose reduction for the beta sources was found to be dependent on the guidewire location. For example, the dose reduction was 10% higher for a stainless steel guidewire located at 0.5 mm than that for the guidewire at 2 mm from the central axis of the source. The portion of the target volume affected (shadowed) dosimetrically by the guidewire was reduced when the guidewire was positioned farther away from the source. The shadow volume (in which the dose reduction occurs) can be reduced by up to 45% as the guidewire is moved away from the source axis from 0.5 mm to 2 mm. The dosimetric perturbations due to the presence of a metallic guidewire as well as their dependence on guidewire location should be considered in designing a new IVBT delivery device, in analysing the treatment efficacy, and/or in dose prescription for a beta source. (author)

  10. Paraspinal tumors: Techniques and results of brachytherapy

    International Nuclear Information System (INIS)

    Because of their proximity to nerve roots and the spinal cord, it is frequently difficult to achieve complete resection of paraspinal tumors. We have used brachytherapy in an attempt to prevent local recurrence and its associated neurological sequelae. This report analyzes our experience with 35 patients to determine the feasibility, optimal techniques, and efficacy of this approach. The tumor types were non small-cell lung cancer (18), sarcomas (9), and other tumor types (8). Temporary, single plane implants using Ir-192 (median minimum peripheral dose 3000 cGy) were used in 21 patients, and permanent I-125 implants were used in 14 cases (median matched peripheral dose 12,500 cGy). Local control was achieved in 51% (18/35). However, local control was poor when lung cancers were implanted and in cases where the dura was exposed. Radiation myelitis did not occur despite the combined effects of previous external beam radiotherapy (N = 21) and brachytherapy. Our experience demonstrates that combined surgery and paraspinal brachytherapy can be performed with acceptable toxicity and is reasonably effective in preventing local relapse and its neurologic sequelae, particularly for tumors other than lung cancers

  11. Brachytherapy treatment with high dose rate

    International Nuclear Information System (INIS)

    Retrospectively analyze results and prognostic factors of cervical cancer patients treated with radio concomitant cisplatin-based chemotherapy, radiation therapy combined modality. Methods: From January 2003 to December 2007, 198 patients with invasive cervical cancer were treated at the Oncology Department of Hospital Robau Celestino Hernandez (brachytherapy performed at INOR). The most common age group was 31 to 40 years. The histology in squamous cell carcinoma accounted for 84.3% of cases. The treatment consisted of external pelvic irradiation and vaginal brachytherapy, high dose rate. Concomitant chemotherapy consisted of cisplatin 40 mg/m2 weekly with a maximum of 70 mg for 5 weeks. Results: 66.2% of patients completed 5 cycles of chemotherapy. The median overall survival was 39 months, overall survival, disease-free survival and survival free of locoregional recurrence at 5 years of 78%, 76% and 78.6% respectively .. We found that clinical stage, histological type (adenocarcinoma worst outcome) were statistically related to level of response. Conclusions: Treatment with external pelvic radiation, brachytherapy and concurrent weekly cisplatin in patients with stage IIIB cervical cancer is feasible in the Chilean public health system, well tolerated and results comparable to international literature. (Author)

  12. Radioactive seed immobilization techniques for interstitial brachytherapy

    Energy Technology Data Exchange (ETDEWEB)

    Yan, K.; Podder, T.; Buzurovic, I.; Hu, Y.; Dicker, A.; Valicenti, R.; Yu, Y. [Thomas Jefferson University, Department of Radiation Oncology, Philadelphia, PA (United States); Messing, E. [University of Rochester, Departments of Urology and Surgery, Rochester, NY (United States); Rubens, D. [University of Rochester, Departments of Imaging Science and Surgery, Rochester, NY (United States); Sarkar, N. [Vanderbilt University, Department of Mechanical Engineering, Nashville, TN (United States); Ng, W. [Nangyang Technical University, School of Mechanical and Aerospace Engineering, Singapore (Singapore)

    2008-06-15

    In prostate brachytherapy, seeds can detach from their deposited sites and move locally in the pelvis or migrate to distant sites including the pulmonary and cardiac regions. Undesirable consequences of seed migration include inadequate dose coverage of the prostate and tissue irradiation effects at the site of migration. Thus, it is clinically important to develop seed immobilization techniques. We first analyze the possible causes for seed movement, and propose three potential techniques for seed immobilization: (1) surgical glue, (2) laser coagulation and (3) diathermy coagulation. The feasibility of each method is explored. Experiments were carried out using fresh bovine livers to investigate the efficacy of seed immobilization using surgical glue. Results have shown that the surgical glue can effectively immobilize the seeds. Evaluation of the radiation dose distribution revealed that the non-immobilized seed movement would change the planned isodose distribution considerably; while by using surgical glue method to immobilize the seeds, the changes were negligible. Prostate brachytherapy seed immobilization is necessary and three alternative mechanisms are promising for addressing this issue. Experiments for exploring the efficacy of the other two proposed methods are ongoing. Devices compatible with the brachytherapy procedure will be designed in future. (orig.)

  13. Office hours pulsed brachytherapy boost in breast cancer

    International Nuclear Information System (INIS)

    Background and purpose: Radiobiological studies suggest equivalent biological effects between continuous low dose rate brachytherapy (CLDR) and pulsed brachytherapy (PB) when pulses are applied without interruption every hour. However, radiation protection and institute-specific demands requested the design of a practical PB protocol substituting the CLDR boost in breast cancer patients. An office hours scheme was designed, considering the CLDR dose rate, the overall treatment time, pulse frequency and tissue repair characteristics. Radiobiological details are presented as well as the logistics and technical feasibility of the scheme after treatment of the first 100 patients. Materials and methods: Biologically effective doses (BEDs) were calculated according to the linear quadratic model for incomplete repair. Radiobiological parameters included an α/β value of 3 Gy for normal tissue late effects and 10 Gy for early normal tissue or tumour effects. Tissue repair half-time ranged from 0.1 to 6 h. The reference CLDR dose rate of 0.80 Gy/h was obtained retrospectively from analysis of patients' data. The treatment procedure was evaluated with regard to variations in implant characteristics after treatment of 100 patients. Results: A PB protocol was designed consisting of two treatment blocks separated by a night break. Dose delivery in PB was 20 Gy in two 10 Gy blocks and, for application of the 15 Gy boost, one 10 Gy block plus one 5 Gy block. The dose per pulse was 1.67 Gy, applied with a period time of approximately 1.5 h. An inter-patient variation of 30% (1 SD) was observed in the instantaneous source strength. Taking also the spread in implant size into account, the net variation in pulse duration amounted to 38%. Conclusion: An office hours PB boost regimen was designed for substitution of the CLDR boost in breast-conserving therapy on the basis of the BED. First treatment experience shows the office hour regimen to be convenient to the patients and no

  14. Radiation Exposure Reduction to Brachytherapy Staff By Using Remote Afterloading

    International Nuclear Information System (INIS)

    The radiation exposures to the personnel staff from patients with brachytherapy implants in a brachytherapy service were reviewed. Exposures to the brachytherapy personnel, as determined by Thermoluminescence Dosimeter (TLD) monitors, indicates a four-fold reduction in exposures after the implantation of the use of remote afterloading devices. Quarterly TLD monitor data for seven quarters prior to the use of remote afterloading devices demonstrate an average projected annual dose equivalent to the brachytherapy staff of 2543 Μ Sv. After the implantation of the remote afterloading devices, the quarterly TLD monitor data indicate an average dose equivalent per person of 153 Μ Sv. This is 76% reduction in exposure to brachytherapy personnel with the use of these devices

  15. Penile brachytherapy: Results for 49 patients

    International Nuclear Information System (INIS)

    Purpose: To report results for 49 men with squamous cell carcinoma (SCC) of the penis treated with primary penile interstitial brachytherapy at one of two institutions: the Ottawa Regional Cancer Center, Ottawa, and the Princess Margaret Hospital, Toronto, Ontario, Canada. Methods and Materials: From September 1989 to September 2003, 49 men (mean age, 58 years; range, 22-93 years) had brachytherapy for penile SCC. Fifty-one percent of tumors were T1, 33% T2, and 8% T3; 4% were in situ and 4% Tx. Grade was well differentiated in 31%, moderate in 45%, and poor in 2%; grade was unspecified for 20%. One tumor was verrucous. All tumors in Toronto had pulsed dose rate (PDR) brachytherapy (n = 23), whereas those in Ottawa had either Iridium wire (n 22) or seeds (n = 4). Four patients had a single plane implant with a plastic tube technique, and all others had a volume implant with predrilled acrylic templates and two or three parallel planes of needles (median, six needles). Mean needle spacing was 13.5 mm (range, 10-18 mm), mean dose rate was 65 cGy/h (range, 33-160 cGy/h), and mean duration was 98.8 h (range, 36-188 h). Dose rates for PDR brachytherapy were 50-61.2 cGy/h, with no correction in total dose, which was 60 Gy in all cases. Results: Median follow-up was 33.4 months (range, 4-140 months). At 5 years, actuarial overall survival was 78.3% and cause-specific survival 90.0%. Four men died of penile cancer, and 6 died of other causes with no evidence of recurrence. The cumulative incidence rate for never having experienced any type of failure at 5 years was 64.4% and for local failure was 85.3%. All 5 patients with local failure were successfully salvaged by surgery; 2 other men required penectomy for necrosis. The soft tissue necrosis rate was 16% and the urethral stenosis rate 12%. Of 8 men with regional failure, 5 were salvaged by lymph node dissection with or without external radiation. All 4 men with distant failure died of disease. Of 49 men, 42 had an intact

  16. BrachyView, a novel in-body imaging system for HDR prostate brachytherapy: Experimental evaluation

    Energy Technology Data Exchange (ETDEWEB)

    Safavi-Naeini, M.; Han, Z.; Alnaghy, S.; Cutajar, D.; Petasecca, M.; Lerch, M. L. F.; Rosenfeld, A. B., E-mail: anatoly@uow.edu.au [Centre for Medical Radiation Physics, University of Wollongong, Wollongong 2522 (Australia); Franklin, D. R. [Faculty of Engineering and Information Technology, University of Technology, Sydney 2007 (Australia); Bucci, J. [St George Hospital Cancer Care Centre, Kogarah 2217 (Australia); Carrara, M. [Fondazione IRCCS Istituto Nazionale dei Tumori, Milan 20133 (Italy); Zaider, M. [Memorial Sloan Kettering Cancer Center, New York, New York 10065 (United States)

    2015-12-15

    Purpose: This paper presents initial experimental results from a prototype of high dose rate (HDR) BrachyView, a novel in-body source tracking system for HDR brachytherapy based on a multipinhole tungsten collimator and a high resolution pixellated silicon detector array. The probe and its associated position estimation algorithms are validated and a comprehensive evaluation of the accuracy of its position estimation capabilities is presented. Methods: The HDR brachytherapy source is moved through a sequence of positions in a prostate phantom, for various displacements in x, y, and z. For each position, multiple image acquisitions are performed, and source positions are reconstructed. Error estimates in each dimension are calculated at each source position and combined to calculate overall positioning errors. Gafchromic film is used to validate the accuracy of source placement within the phantom. Results: More than 90% of evaluated source positions were estimated with an error of less than one millimeter, with the worst-case error being 1.3 mm. Experimental results were in close agreement with previously published Monte Carlo simulation results. Conclusions: The prototype of HDR BrachyView demonstrates a satisfactory level of accuracy in its source position estimation, and additional improvements are achievable with further refinement of HDR BrachyView’s image processing algorithms.

  17. BrachyView, a novel in-body imaging system for HDR prostate brachytherapy: Experimental evaluation

    International Nuclear Information System (INIS)

    Purpose: This paper presents initial experimental results from a prototype of high dose rate (HDR) BrachyView, a novel in-body source tracking system for HDR brachytherapy based on a multipinhole tungsten collimator and a high resolution pixellated silicon detector array. The probe and its associated position estimation algorithms are validated and a comprehensive evaluation of the accuracy of its position estimation capabilities is presented. Methods: The HDR brachytherapy source is moved through a sequence of positions in a prostate phantom, for various displacements in x, y, and z. For each position, multiple image acquisitions are performed, and source positions are reconstructed. Error estimates in each dimension are calculated at each source position and combined to calculate overall positioning errors. Gafchromic film is used to validate the accuracy of source placement within the phantom. Results: More than 90% of evaluated source positions were estimated with an error of less than one millimeter, with the worst-case error being 1.3 mm. Experimental results were in close agreement with previously published Monte Carlo simulation results. Conclusions: The prototype of HDR BrachyView demonstrates a satisfactory level of accuracy in its source position estimation, and additional improvements are achievable with further refinement of HDR BrachyView’s image processing algorithms

  18. Erectile function after permanent prostate brachytherapy

    International Nuclear Information System (INIS)

    Purpose: To determine the incidence of potency preservation after permanent prostate brachytherapy using a validated patient-administered questionnaire and to evaluate the effect of multiple clinical and treatment parameters on penile erectile function. Methods and Materials: Four hundred twenty-five patients underwent permanent prostate brachytherapy from April 1995 to October 1999. Two hundred nine patients who were potent before brachytherapy and who at the time of the survey were not receiving hormonal therapy were mailed the specific erectile questions of the International Index of Erectile Function (IIEF) questionnaire with a self-addressed stamped envelope. The questionnaire consisted of 5 questions, with a maximal score of 25. Of the 209 patients, 181 (87%) completed and returned the questionnaire. The mean and median follow-up was 40.4±14.9 and 40.6 months, respectively (range 19-75). Preimplant erectile function was assigned using a three-tiered scoring system (2 = erections always or nearly always sufficient for vaginal penetration; 1 = erections sufficient for vaginal penetration but considered suboptimal; 0 = the inability to obtain erections and/or erections inadequate for vaginal penetration). Postimplant potency was defined as an IIEF score ≥11. The clinical parameters evaluated for erectile function included patient age, preimplant potency, clinical T-stage, pretreatment prostate-specific antigen level, Gleason score, elapsed time after implantation, hypertension, diabetes mellitus, and tobacco consumption. Treatment parameters included radiation dose to the prostate gland, use of hormonal manipulation, use of supplemental external beam radiotherapy (EBRT), choice of isotope, prostate volume, and planning volume. The efficacy of sildenafil citrate in brachytherapy-induced erectile dysfunction (ED) was also evaluated. Results: Pretreatment erectile function scores of 2 and 1 were assigned to 125 and 56 patients, respectively. With a 6-year follow

  19. SU-E-T-564: Multi-Helix Rotating Shield Brachytherapy for Cervical Cancer

    International Nuclear Information System (INIS)

    Purpose: To present a novel and practical brachytherapy technique, called multi-helix rotating shield brachytherapy (H-RSBT), for the precise positioning of a partial shield in a curved applicator. H-RSBT enables RSBT delivery using only translational motion of the radiation source/shield combination. H-RSBT overcomes the challenges associated with previously proposed RSBT approaches based on a serial (S-RSBT) step-and-shoot delivery technique, which required independent translational and rotational motion. Methods: A Fletcher-type applicator, compatible with the combination of a Xoft Axxent™ electronic brachytherapy source and a 0.5 mm thick tungsten shield, is proposed. The wall of the applicator contains six evenly-spaced helical keyways that rigidly define the emission direction of the shield as a function of depth. The shield contains three protruding keys and is attached to the source such that it rotates freely. S-RSBT and H-RSBT treatment plans with 180° and 45° azimuthal emission angles were generated for five cervical cancer patients representative of a wide range of high-risk clinical target volume (HR-CTV) shapes and applicator positions. The number of beamlets used in the treatment planning process was nearly constant for S-RSBT and H-RSBT by using dwell positions separated by 5 and 1.7 mm, respectively, and emission directions separated by 22.5° and 60°, respectively. For all the treatment plans the EQD2 of the HR-CTV was escalated until the EQD2cc tolerance of either the bladder, rectum, or sigmoid colon was reached. Results: Treatment times for H-RSBT tended to be shorter than for S-RSBT, with changes of −38.47% to 1.12% with an average of −8.34%. The HR-CTV D90 changed by −8.81% to 2.08% with an average of −2.46%. Conclusion: H-RSBT is a mechanically feasible technique in the curved applicators needed for cervical cancer brachytherapy. S-RSBT and H-RSBT dose distributions were clinically equivalent for all patients considered, with

  20. SU-E-T-564: Multi-Helix Rotating Shield Brachytherapy for Cervical Cancer

    Energy Technology Data Exchange (ETDEWEB)

    Dadkhah, H; Wu, X [University of Iowa, Iowa City, IA (United States); Flynn, R; Kim, Y [University of Iowa Hospitals and Clinics, Iowa City, IA (United States)

    2015-06-15

    Purpose: To present a novel and practical brachytherapy technique, called multi-helix rotating shield brachytherapy (H-RSBT), for the precise positioning of a partial shield in a curved applicator. H-RSBT enables RSBT delivery using only translational motion of the radiation source/shield combination. H-RSBT overcomes the challenges associated with previously proposed RSBT approaches based on a serial (S-RSBT) step-and-shoot delivery technique, which required independent translational and rotational motion. Methods: A Fletcher-type applicator, compatible with the combination of a Xoft Axxent™ electronic brachytherapy source and a 0.5 mm thick tungsten shield, is proposed. The wall of the applicator contains six evenly-spaced helical keyways that rigidly define the emission direction of the shield as a function of depth. The shield contains three protruding keys and is attached to the source such that it rotates freely. S-RSBT and H-RSBT treatment plans with 180° and 45° azimuthal emission angles were generated for five cervical cancer patients representative of a wide range of high-risk clinical target volume (HR-CTV) shapes and applicator positions. The number of beamlets used in the treatment planning process was nearly constant for S-RSBT and H-RSBT by using dwell positions separated by 5 and 1.7 mm, respectively, and emission directions separated by 22.5° and 60°, respectively. For all the treatment plans the EQD2 of the HR-CTV was escalated until the EQD{sub 2cc} tolerance of either the bladder, rectum, or sigmoid colon was reached. Results: Treatment times for H-RSBT tended to be shorter than for S-RSBT, with changes of −38.47% to 1.12% with an average of −8.34%. The HR-CTV D{sub 90} changed by −8.81% to 2.08% with an average of −2.46%. Conclusion: H-RSBT is a mechanically feasible technique in the curved applicators needed for cervical cancer brachytherapy. S-RSBT and H-RSBT dose distributions were clinically equivalent for all patients

  1. Dosimetric and clinical comparison between MammoSite and interstitial HDR brachytherapy in treatment of early stage breast cancer after conserving surgery

    International Nuclear Information System (INIS)

    Objective: To comparatively study dosimetric evaluation, side effects in early and late stage, and cosmetic outcome between MammoSite and interstitial using high-dose-rate (HDR) brachytherapy accelerated partial breast irradiation (APBI) in early stage breast cancer patient after conserving surgery. Methods: From January 2004 to December 2004, 10 breast cancer cases were treated with HDR 192Ir APBI after Lumpectomy surgery, 6 cases with interstitial brachytherapy, 4 cases with MammoSite. Sources were placed during the operation in all patients, distance from cavity to skin > 5-7 mm in interstitial brachytherapy group, one case is 6.5 mm, 3 cases > 10 mm in MammoSite group. Treatment Target area is 20 mm away from cavity in interstitial brachytherapy group with DHI 0.77, 10 mm away from Balloon margin in MammoSite with DHI 0.73. Results: Follow up 12-24 months while median follow-up was 18 months for the whole group (100%). During the treatment, grade III acute reactions were not seen in both group, grade I or II were seen including: erythema, edema, tenderness and infection. More late toxicity reaction including skin fibrosis, breast tenderness and fat necrosis were observed in interstitial brachytherapy group than that of MammoSite group. Cosmetic outcome evaluation were excellent in 12 months 100% (patient) and 83% (doctor) in interstitial brachytherapy, 100% in MammoSite group, respectively, none recurrence. Conclusions: Interstitial brachytherapy shows more uniformity in dose distribution as well as larger treatment volume, while MammoSite tends to be stable in repeatability and easy in use. Both groups show excellent cosmetic results, with same acute and late reactions. (authors)

  2. Radiation exposure to operating room staff during prostate brachytherapy using iodine-125 seeds

    International Nuclear Information System (INIS)

    The French defense radiation protection service (SPRA) and the French national institute for research and safety (INRS) conducted a joint study to assess the radiation exposure to operating room staff during prostate brachytherapy using iodine-125 seeds at the Val-de-Grace military hospital. The purpose of the study was the assessment of the effective doses, the equivalent doses to the extremities and lens received by a novice team, the different ambient dose equivalent rates measurements and the delineation of areas. After six brachy-therapies, all the recorded doses with whole-body InLightR OSL and nanoDotR dosimeters remained below the detection limit for the whole staff. The dose rate measured at the end of implantation by an AT1123R survey meter is about 170 μSv/h at the perineum of the patient. The controlled area limit is estimated to be about 20 cm from the patient perineum. From these results, the authors propose recommendations for the categorization of workers, the delineation of areas and the dose monitoring procedures. This study demonstrates that real-time ultrasound-guided trans-perineal prostate brachytherapy delivers low dose to the operators because of the radioactive source characteristics and the instrumentation providing an effective radiation protection for the surgical team. (authors)

  3. Prospective multi-center trial utilizing electronic brachytherapy for the treatment of endometrial cancer

    International Nuclear Information System (INIS)

    A modified form of high dose rate (HDR) brachytherapy has been developed called Axxent Electronic Brachytherapy (EBT). EBT uses a kilovolt X-ray source and does not require treatment in a shielded vault or a HDR afterloader unit. A multi-center clinical study was carried out to evaluate the success of treatment delivery, safety and toxicity of EBT in patients with endometrial cancer. A total of 15 patients with stage I or II endometrial cancer were enrolled at 5 sites. Patients were treated with vaginal EBT alone or in combination with external beam radiation. The prescribed doses of EBT were successfully delivered in all 15 patients. From the first fraction through 3 months follow-up, there were 4 CTC Grade 1 adverse events and 2 CTC Grade II adverse events reported that were EBT related. The mild events reported were dysuria, vaginal dryness, mucosal atrophy, and rectal bleeding. The moderate treatment related adverse events included dysuria, and vaginal pain. No Grade III or IV adverse events were reported. The EBT system performed well and was associated with limited acute toxicities. EBT shows acute results similar to HDR brachytherapy. Additional research is needed to further assess the clinical efficacy and safety of EBT in the treatment of endometrial cancer

  4. Brachytherapy of stage II mobile tongue carcinoma. Prediction of local control and QOL

    Directory of Open Access Journals (Sweden)

    Watanabe Hiroshi

    2006-07-01

    Full Text Available Abstract Background There is no consensus as to the prognostic model for brachytherapy of tongue carcinoma. This study was designed to evaluate the prognostic factors for local control based on a large population under a unified treatment policy. Results Between 1970 and 1998, 433 patients with stage II tongue squamous cell carcinoma were treated by low-dose-rate brachytherapy. This series included 277 patients treated with a linear source with a minimum follow-up of 3 years. A spacer was introduced in 1987. The primary local control rates were 85.6%. Conclusion In the multivariate analysis, an invasive growth pattern was a significant factor for local recurrence. The disease-related survival was influenced by old age and an invasive growth pattern. A spacer lowered mandibular bone complications. The growth pattern was the most important factor for recurrence. Brachytherapy was associated with a high cure rate and the use of spacers brought about good quality of life (QOL.

  5. Quality control of the breast cancer treatments on Hdr brachytherapy with TLD-100

    International Nuclear Information System (INIS)

    An anthropomorphic Phantom, a female trunk, was built with a natural bone structure and experimental material coated, glycerin and water-based material called JJT to build soft tissue equivalent to the muscle of human tissue, and a polymer (styrofoam) to build the lung as critical organ to simulate the treatment of breast cancer, with high dose rate brachytherapy (Hdr) and sources of Ir-192. The treatments were planned and calculated for the critical organ: Lung, and injury of 2 cm in diameter in breast with Micro Selectron Hdr system and the software Plato Brachytherapy V 14.1 of the Nucletron (Netherlands) which uses the standard protocol of radiotherapy for brachytherapy treatments. The dose experimentally measured with dosimeters TLD-100 LiF: Mg; Ti, which were previously calibrated, were placed in the same positions and bodies mentioned above, with less than 5% uncertainty. The reading dosimeters was carried out in a Harshaw TLD 4500. The results obtained for calculated treatments, using the standard simulator, and the experimental with TLD-100, show a high concordance, as they are on average a ± 1.1% making process becomes in a quality control of this type of treatments. (Author)

  6. Current Brachytherapy Quality Assurance Guidance: Does It Meet the Challenges of Emerging Image-Guided Technologies?

    International Nuclear Information System (INIS)

    In the past decade, brachytherapy has shifted from the traditional surgical paradigm to more modern three-dimensional image-based planning and delivery approaches. The role of intraoperative and multimodality image-based planning is growing. Published American Association of Physicists in Medicine, American College of Radiology, European Society for Therapeutic Radiology and Oncology, and International Atomic Energy Agency quality assurance (QA) guidelines largely emphasize the QA of planning and delivery devices rather than processes. These protocols have been designed to verify compliance with major performance specifications and are not risk based. With some exceptions, complete and clinically practical guidance exists for sources, QA instrumentation, non-image-based planning systems, applicators, remote afterloading systems, dosimetry, and calibration. Updated guidance is needed for intraoperative imaging systems and image-based planning systems. For non-image-based brachytherapy, the American Association of Physicists in Medicine Task Group reports 56 and 59 provide reasonable guidance on procedure-specific process flow and QA. However, improved guidance is needed even for established procedures such as ultrasound-guided prostate implants. Adaptive replanning in brachytherapy faces unsolved problems similar to that of image-guided adaptive external beam radiotherapy

  7. Prospective multi-center trial utilizing electronic brachytherapy for the treatment of endometrial cancer

    Directory of Open Access Journals (Sweden)

    Thropay John P

    2010-07-01

    Full Text Available Abstract Background A modified form of high dose rate (HDR brachytherapy has been developed called Axxent Electronic Brachytherapy (EBT. EBT uses a kilovolt X-ray source and does not require treatment in a shielded vault or a HDR afterloader unit. A multi-center clinical study was carried out to evaluate the success of treatment delivery, safety and toxicity of EBT in patients with endometrial cancer. Methods A total of 15 patients with stage I or II endometrial cancer were enrolled at 5 sites. Patients were treated with vaginal EBT alone or in combination with external beam radiation. Results The prescribed doses of EBT were successfully delivered in all 15 patients. From the first fraction through 3 months follow-up, there were 4 CTC Grade 1 adverse events and 2 CTC Grade II adverse events reported that were EBT related. The mild events reported were dysuria, vaginal dryness, mucosal atrophy, and rectal bleeding. The moderate treatment related adverse events included dysuria, and vaginal pain. No Grade III or IV adverse events were reported. The EBT system performed well and was associated with limited acute toxicities. Conclusions EBT shows acute results similar to HDR brachytherapy. Additional research is needed to further assess the clinical efficacy and safety of EBT in the treatment of endometrial cancer.

  8. Quality control of the breast cancer treatments on Hdr brachytherapy with TLD-100

    Energy Technology Data Exchange (ETDEWEB)

    Torres H, F. [Universidad de Cordoba, Materials and Applied Physics Group, 230002 Monteria, Cordoba (Colombia); De la Espriella V, N. [Universidad de Cordoba, Grupo Avanzado de Materiales y Sistemas Complejos, 230002 Monteria, Cordoba (Colombia); Sanchez C, A., E-mail: franciscotorreshoyos@yahoo.com [Universidad de Cordoba, Departamento de Enfermeria, 230002 Monteria, Cordoba (Colombia)

    2014-07-01

    An anthropomorphic Phantom, a female trunk, was built with a natural bone structure and experimental material coated, glycerin and water-based material called JJT to build soft tissue equivalent to the muscle of human tissue, and a polymer (styrofoam) to build the lung as critical organ to simulate the treatment of breast cancer, with high dose rate brachytherapy (Hdr) and sources of Ir-192. The treatments were planned and calculated for the critical organ: Lung, and injury of 2 cm in diameter in breast with Micro Selectron Hdr system and the software Plato Brachytherapy V 14.1 of the Nucletron (Netherlands) which uses the standard protocol of radiotherapy for brachytherapy treatments. The dose experimentally measured with dosimeters TLD-100 LiF: Mg; Ti, which were previously calibrated, were placed in the same positions and bodies mentioned above, with less than 5% uncertainty. The reading dosimeters was carried out in a Harshaw TLD 4500. The results obtained for calculated treatments, using the standard simulator, and the experimental with TLD-100, show a high concordance, as they are on average a ± 1.1% making process becomes in a quality control of this type of treatments. (Author)

  9. Evaluation of PC-ISO for customized, 3D Printed, gynecologic 192-Ir HDR brachytherapy applicators.

    Science.gov (United States)

    Cunha, J Adam M; Mellis, Katherine; Sethi, Rajni; Siauw, Timmy; Sudhyadhom, Atchar; Garg, Animesh; Goldberg, Ken; Hsu, I-Chow; Pouliot, Jean

    2015-01-01

    The purpose of this study was to evaluate the radiation attenuation properties of PC-ISO, a commercially available, biocompatible, sterilizable 3D printing material, and its suitability for customized, single-use gynecologic (GYN) brachytherapy applicators that have the potential for accurate guiding of seeds through linear and curved internal channels. A custom radiochromic film dosimetry apparatus was 3D-printed in PC-ISO with a single catheter channel and a slit to hold a film segment. The apparatus was designed specifically to test geometry pertinent for use of this material in a clinical setting. A brachytherapy dose plan was computed to deliver a cylindrical dose distribution to the film. The dose plan used an 192Ir source and was normalized to 1500 cGy at 1 cm from the channel. The material was evaluated by comparing the film exposure to an identical test done in water. The Hounsfield unit (HU) distributions were computed from a CT scan of the apparatus and compared to the HU distribution of water and the HU distribution of a commercial GYN cylinder applicator. The dose depth curve of PC-ISO as measured by the radiochromic film was within 1% of water between 1 cm and 6 cm from the channel. The mean HU was -10 for PC-ISO and -1 for water. As expected, the honeycombed structure of the PC-ISO 3D printing process created a moderate spread of HU values, but the mean was comparable to water. PC-ISO is sufficiently water-equivalent to be compatible with our HDR brachytherapy planning system and clinical workflow and, therefore, it is suitable for creating custom GYN brachytherapy applicators. Our current clinical practice includes the use of custom GYN applicators made of commercially available PC-ISO when doing so can improve the patient's treatment.  PMID:25679174

  10. Fricke gel dosimetric catheters in high dose rate brachytherapy. In phantom dose distribution measurements of a 5 catheter implant

    International Nuclear Information System (INIS)

    Due to the complexity and the many steps involved in a high dose rate brachytherapy process, radiation dose delivered to the patient during the treatment is susceptible to many inaccuracies and may not accurately match the planned dose. In vivo dosimetry is a reliable solution to compare planned and delivered dose distributions, representing therefore a valid tool to systematically perform a quality control of the radiotherapic process and eventually increment treatment accuracy. In this study, Fricke gel dosimetric catheters (FGDC) were investigated to perform dose distribution measurements of a brachytherapy implant. The brachytherapy implant was established in a water phantom with five flexible plastic needles and irradiation was performed with a high dose rate remote afterloading device provided with an Ir-192 radioactive source. Comparison between dose distributions measured with ten FGDC located in the proximity of the implant needles and calculated by the treatment planning system shows very good agreement for seven out of ten dosimeters, whereas the remaining three show a local underestimation of the dose. In phantom results indicate that Fricke gel dosimetric catheters might be valid candidates for performing in vivo dosimetry in high dose rate brachytherapy. However, further measurements are still required to validate this dosimetric method.

  11. Characterization of a Ce3+ doped SiO2 optical dosimeter for dose measurements in HDR brachytherapy

    International Nuclear Information System (INIS)

    Aim of this work was to study the application of a new miniaturized Ce3+ doped SiO2 scintillation detector to in vivo dosimetry in high dose rate brachytherapy. Energy, dose-rate, temperature and angular dependences of the detector response to 192Ir HDR brachytherapy fields were investigated, as well as sensitivity reproducibility and linearity. To this aim, two ad hoc phantoms were designed and developed to perform measurements in water. Intra-session reproducibility resulted to be very high, however inter-session reproducibility showed too high statistical variation. Detector response resulted to increase linearly with dose (R2 = 0.997), with no evidence of energy and dose-rate dependence. Sensitivity resulted to increase linearly with temperature (R2 = 0.995), with a 0.2% increase each °C. Finally, no significant angular dependence for the source moving around a circle in the azimuthal plane centered at the scintillator was observed. The obtained results show that the proposed detector is suitable for in vivo real-time dosimetry in high dose rate brachytherapy. -- Highlights: •A Ce3+ doped SiO2 scintillation detector was applied to 192Ir HDR brachytherapy. •Detector response resulted to be linear with the delivered dose. •No evidence of energy and dose rate dependence resulted from the study

  12. Brachytherapy using holmium-166 liquid balloon system for in-stent restenosis: 6 months clinical and angiographic follow-up

    International Nuclear Information System (INIS)

    In western country, 3 systems of brachytherapy using commercial radioactive source has been established. However, brachytherapy using holmium-166 liquid balloon system (HLBS) for the patient with stent restenosis has not been studied enough. 30 patients (male 23, mean age 58.9 7.7) were enrolled. Target dose was 15 Gy at 1 mm distance from the intimal surface. Clinical diagnoses of the study patients included stable angina 10 and unstable angina 20 patients. Target lesion included LAD 19, LCx 5 and RCA 6 arteries. Pre-brachytherapy treatment included cutting balloon angioplasty in 25, rotational atherectomy in 5 patients. Fractionation and stepping was done in 6 patients each. Follow-up angiography was done in 19 patients. Of them, 4 cases developed angiographic restenosis (21%) including 3 cases of total occlusion. 6 month MACE (major adverse cardiac event) occurred in 5 patients including one sudden cardiac death in a patient with 80 year-old, triple-vessel diseased patient. Vascular brachytherapy using HLBS is a safe and effective treatment modality for in-stent restenosis showing acceptable angiographic and clinical result

  13. Anisotropy measurement of {sup 192} Ir sources used in high dose rate brachytherapy; Medida da anisotropia de fontes de Ir-192 utilizadas em braquiterapia de altas taxa de dose

    Energy Technology Data Exchange (ETDEWEB)

    Henn, Keli Cristina; Khoury, Helen J.; Luz, Lidia Cristina P. da [Pernambuco Univ., Recife, PE (Brazil). Dept. de Energia Nuclear

    1998-07-01

    This paper presents the dose distribution around the Ir-192 source used in MicroSelectron-HDR remote after loader system. The measurements were made in air with the source stationary, positioned at the position 1, from the indexer of the microSelectron-HDR. Measurements were made using TLD and for radial distances of 3.0, 5.0 and 7.0 cm, for values of the angle from 0 deg c to 360 deg C in steps of 15 deg C. (author)

  14. Use of water-equivalent plastic scintillator for intravascular brachytherapy dosimetry.

    Science.gov (United States)

    Geso, M; Robinson, N; Schumer, W; Williams, K

    2004-03-01

    Beta irradiation has recently been investigated as a possible technique for the prevention of restenosis in intravascular brachytherapy after balloon dilatation or stent implantation. Present methods of beta radiation dosimetry are primarily conducted using radiochromic film. These film dosimeters exhibit limited sensitivity and their characteristics differ from those of tissue, therefore the dose measurement readings require correction factors to be applied. In this work a novel, mini-size (2 mm diameter by 5 mm long) dosimeter element fabricated from Organic Plastic Scintillator (OPS) material was employed. Scintillation photon detection is accomplished using a precision photodiode and innovative signal amplification and processing techniques, rather than traditional photomultiplier tube methods. A significant improvement in signal to noise ratio, dynamic range and stability is achieved using this set-up. In addition, use of the non-saturating organic plastic scintillator material as the detector enables the dosimeter to measure beta radiation at very close distances to the source. In this work the plastic scintillators have been used to measure beta radiation dose at distances of less than 1 mm from an Sr-90 cardiovascular brachytherapy source having an activity of about 2.1 GBq beta radiation levels for both depth-distance and longitudinal profile of the source pellet chain, both in air and in liquid water, are measured using this system. The data obtained is compared with results from Monte Carlo simulation technique (MCNP 4B). Plastic scintillator dosimeter elements, when used in conjunction with photodiode detectors may prove to be useful dosimeters for cardiovascular brachytherapy beta sources, or other applications where precise near-source field dosimetry is required. The system described is particularly useful where measurement of actual dose rate in real time, a high level of stability and repeatability, portability, and immediate access to results are

  15. Suitability of point kernel dose calculation techniques in brachytherapy treatment planning

    Directory of Open Access Journals (Sweden)

    Lakshminarayanan Thilagam

    2010-01-01

    Full Text Available Brachytherapy treatment planning system (TPS is necessary to estimate the dose to target volume and organ at risk (OAR. TPS is always recommended to account for the effect of tissue, applicator and shielding material heterogeneities exist in applicators. However, most brachytherapy TPS software packages estimate the absorbed dose at a point, taking care of only the contributions of individual sources and the source distribution, neglecting the dose perturbations arising from the applicator design and construction. There are some degrees of uncertainties in dose rate estimations under realistic clinical conditions. In this regard, an attempt is made to explore the suitability of point kernels for brachytherapy dose rate calculations and develop new interactive brachytherapy package, named as BrachyTPS, to suit the clinical conditions. BrachyTPS is an interactive point kernel code package developed to perform independent dose rate calculations by taking into account the effect of these heterogeneities, using two regions build up factors, proposed by Kalos. The primary aim of this study is to validate the developed point kernel code package integrated with treatment planning computational systems against the Monte Carlo (MC results. In the present work, three brachytherapy applicators commonly used in the treatment of uterine cervical carcinoma, namely (i Board of Radiation Isotope and Technology (BRIT low dose rate (LDR applicator and (ii Fletcher Green type LDR applicator (iii Fletcher Williamson high dose rate (HDR applicator, are studied to test the accuracy of the software. Dose rates computed using the developed code are compared with the relevant results of the MC simulations. Further, attempts are also made to study the dose rate distribution around the commercially available shielded vaginal applicator set (Nucletron. The percentage deviations of BrachyTPS computed dose rate values from the MC results are observed to be within plus/minus 5

  16. Applicability of a prototype for determination of absorbed dose using brachytherapy equipment with Ir-192 sources; Aplicabilidade de um prototipo para determinacao da dose absorvida utilizando equipamentos de braquiterapia com fontes de IR-192

    Energy Technology Data Exchange (ETDEWEB)

    Souza, Vivianne Lucia Bormann; Almeida, Mayara Gabriella Oliveira de; Vieira, Rafaela Etelvina de Amorim; Silva, Waldecy Ananias da; Nascimento, Rizia Keila, E-mail: vlsouza@cnen.gov.br, E-mail: mayaradqf@hotmail.com, E-mail: rodriguesss@hootmail.com, E-mail: waldecy@cnen.gov.br, E-mail: riziakeila@hotmail.com [Centro Regional de Ciencias Nucleares do Nordeste (CRCN-NE/CNEN-PE), Recife, PE (Brazil)

    2014-07-01

    This work aims at the development and improvement of a device to perform the absolute dosimetry sources of Ir-192 using the Fricke solution contained in a flask. The Fricke solution used was prepared using amounts of ferrous ammonium sulfate, sodium chloride and sulfuric acid, diluted with water tri distilled pre-established in the literature. The spectrophotometer used was a UV-VIS spectrophotometer (Beckman DU-640 Counter) for measuring the optical density at wavelength 304 nm. The calculation for determining the radial dose takes into account the radial distance and the angle formed with the transverse axis of the source. As the results obtained can be seen that the states of Pernambuco, Ceara, Paraiba e Piaui are in accordance with the recommendations of international standards of the International Atomic Energy Agency (IAEA), which considers not acceptable a difference greater than 5% of prescribed dose and measured dose.

  17. Caudal epidural anesthesia during intracavitary brachytherapy for cervical cancer

    International Nuclear Information System (INIS)

    It has been suggested that pain control during intracavitary brachytherapy for cervical cancer is insufficient in most hospitals in Japan. Our hospital began using caudal epidural anesthesia during high-dose-rate (HDR) intracavitary brachytherapy in 2011. The purpose of the present study was to retrospectively investigate the effects of caudal epidural anesthesia during HDR intracavitary brachytherapy for cervical cancer patients. Caudal epidural anesthesia for 34 cervical cancer patients was performed during HDR intracavitary brachytherapy between October 2011 and August 2013. We used the patients' self-reported Numeric Rating Scale (NRS) score at the first session of HDR intracavitary brachytherapy as a subjective evaluation of pain. We compared NRS scores of the patients with anesthesia with those of 30 patients who underwent HDR intracavitary brachytherapy without sacral epidural anesthesia at our hospital between May 2010 and August 2011. Caudal epidural anesthesia succeeded in 33 patients (97%), and the NRS score was recorded in 30 patients. The mean NRS score of the anesthesia group was 5.17 ± 2.97, significantly lower than that of the control group's 6.80 ± 2.59 (P = 0.035). The caudal epidural block resulted in no side-effects. Caudal epidural anesthesia is an effective and safe anesthesia option during HDR intracavitary brachytherapy for cervical cancer. (author)

  18. Radiation Protection in Brachytherapy in the Next Decade

    International Nuclear Information System (INIS)

    Brachytherapy procedures are increasing in number, and account for an important share of radiation exposure in medicine at a time when there is a dramatic rise in cancer across the developing world. Important areas in relation to radiation safety in brachytherapy include that all efforts be made to ensure that protection in the treatment is optimized and all measures are taken to prevent accidental exposures from occurring. Historical and ongoing accidents that have resulted in patient and public doses or inappropriate medical outcomes represent opportunities for continuous improvement in radiation protection. Additionally, staff in brachytherapy treatment facilities may receive high radiation doses if radiological protection tools are not used properly. Brachytherapy uniquely presents the possibility for doses that require active management. In modern brachytherapy centres, radiation doses are incurred by staff (e.g. loading of seeds, plaques, caesium implants, associated fluoroscopy). There is also a large variation in the practice of brachytherapy on a global scale and several facilities still practise older techniques with significantly higher staff dose potential. In addition, technological developments and newer techniques present new radiation protection concerns and an increasing blurring of historical responsibilities that need to be addressed with specific recommendations for the practising medical community. Along with an increase in equipment and to safeguard resources, additional qualified and trained brachytherapy staff are required worldwide. (author)

  19. Application of TSH bioindicator for studying the biological efficiency of radiation

    International Nuclear Information System (INIS)

    Dose response relationships for various endpoints (gene and lethal mutations, cell cycle alterations) in somatic cells of Tradescantia clone 4430 were established for X-rays and for mixed fast and thermal neutrons from Cf-252 source of KAERI and from U-120 cyclotron of INP. This was a pilot experiment to check if it is possible to establish the relative biological effectiveness values for Cf-252 irradiated TSH cells, with and without boron ion pretreatment, in conditions of mutual KAERI-INP experiment. When T-4430 was pretreated with boron ion, there was and enhancement in biological efficacy of neutron form Cf-252 source. 2 tabs., 7 figs., 7 refs. (Author)

  20. Perioperative interstitial brachytherapy for recurrent keloid scars

    International Nuclear Information System (INIS)

    Purpose: Evaluation of the results of perioperative interstitial brachytherapy with low dose-rate (L.D.R.) Ir-192 in the treatment of keloid scars. Patients and methods: We performed a retrospective analysis of 73 histologically confirmed keloids (from 58 patients) resistant to medico surgical treated by surgical excision plus early perioperative brachytherapy. All lesions were initially symptomatic. Local control was evaluated by clinical evaluation. Functional and cosmetic results were assessed in terms of patient responses to a self-administered questionnaire. Results: Median age was 28 years (range 13-71 years). Scars were located as follows: 37% on the face, 32% on the trunk or abdomen, 16% on the neck, and 15% on the arms or legs. The mean delay before loading was four hours (range, 1-6 h). The median dose was 20 Gy (range, 15-40 Gy). Sixty-four scars (from 53 patients) were evaluated. Local control was 86% (follow-up, 44.5 months; range, 14-150 months). All relapses occurred early within 2 years posttreatment. At 20 months, survival without recurrence was significantly lower when treated lengths were more than 6 cm long. The rate was 100% for treated scars below 4.5 cm in length, 95% (95% CI: 55-96) for those 4.5-6 cm long, and 75% (95% CI: 56-88) beyond 6 cm (p = 0.038). Of the 35 scars (28 patients) whose results were reassessed, six remained symptomatic and the esthetic results were considered to be good in 51% (18/35) and average in 37% (13/35) (median follow-up, 70 months; range, 16-181 months). Conclusion: Early perioperative L.D.R. brachytherapy delivering 20 Gy at 5 mm reduced the rate of recurrent keloids resistant to other treatments and gave good functional results. (authors)

  1. Use of Monte Carlo Methods for determination of isodose curves in brachytherapy

    International Nuclear Information System (INIS)

    Brachytherapy is a special form of cancer treatment in which the radioactive source is very close to or inside the tumor with the objective of causing the necrosis of the cancerous tissue. The intensity of cell response to the radiation varies according to the tissue type and degree of differentiation. Since the malign cells are less differentiated than the normal ones, they are more sensitive to the radiation. This is the basis for radiotherapy techniques. Institutes that work with the application of high dose rates use sophisticated computer programs to calculate the necessary dose to achieve the necrosis of the tumor and the same time, minimizing the irradiation of tissues and organs of the neighborhood. With knowledge the characteristics of the source and the tumor, it is possible to trace isodose curves with the necessary information for planning the brachytherapy in patients. The objective of this work is, using Monte Carlo techniques, to develop a computer program - the ISODOSE - which allows to determine isodose curves in turn of linear radioactive sources used in brachytherapy. The development of ISODOSE is important because the available commercial programs, in general, are very expensive and practically inaccessible to small clinics. The use of Monte Carlo techniques is viable because they avoid problems inherent to analytic solutions as, for instance , the integration of functions with singularities in its domain. The results of ISODOSE were compared with similar data found in the literature and also with those obtained at the institutes of radiotherapy of the 'Hospital do Cancer do Recife' and of the 'Hospital Portugues do Recife'. ISODOSE presented good performance, mainly, due to the Monte Carlo techniques, that allowed a quite detailed drawing of the isodose curves in turn of linear sources. (author)

  2. Sensitivity of low energy brachytherapy Monte Carlo dose calculations to uncertainties in human tissue composition

    International Nuclear Information System (INIS)

    Purpose: The objective of this work is to assess the sensitivity of Monte Carlo (MC) dose calculations to uncertainties in human tissue composition for a range of low photon energy brachytherapy sources: 125I, 103Pd, 131Cs, and an electronic brachytherapy source (EBS). The low energy photons emitted by these sources make the dosimetry sensitive to variations in tissue atomic number due to the dominance of the photoelectric effect. This work reports dose to a small mass of water in medium Dw,m as opposed to dose to a small mass of medium in medium Dm,m. Methods: Mean adipose, mammary gland, and breast tissues (as uniform mixture of the aforementioned tissues) are investigated as well as compositions corresponding to one standard deviation from the mean. Prostate mean compositions from three different literature sources are also investigated. Three sets of MC simulations are performed with the GEANT4 code: (1) Dose calculations for idealized TG-43-like spherical geometries using point sources. Radial dose profiles obtained in different media are compared to assess the influence of compositional uncertainties. (2) Dose calculations for four clinical prostate LDR brachytherapy permanent seed implants using 125I seeds (Model 2301, Best Medical, Springfield, VA). The effect of varying the prostate composition in the planning target volume (PTV) is investigated by comparing PTV D90 values. (3) Dose calculations for four clinical breast LDR brachytherapy permanent seed implants using 103Pd seeds (Model 2335, Best Medical). The effects of varying the adipose/gland ratio in the PTV and of varying the elemental composition of adipose and gland within one standard deviation of the assumed mean composition are investigated by comparing PTV D90 values. For (2) and (3), the influence of using the mass density from CT scans instead of unit mass density is also assessed. Results: Results from simulation (1) show that variations in the mean compositions of tissues affect low energy

  3. Feasibility of MatriXX 2D detector array for HDR brachytherapy planning system assessment

    International Nuclear Information System (INIS)

    IBA Dosimetry GmbH participated in the Joint Research Project 'Increasing cancer treatment efficacy using 3D brachytherapy' as a non-funded partner in the work package which was mostly dedicated to the determination of dose-to-water distribution from a high-dose-rate (HDR) brachytherapy source. The dose distribution was measured with a MatriXX (MXX) 2D detector array and compared with Dose Cube Data, calculated by treatment planning systems (TPS). All measurements and calculations were performed in cooperation with OUSA, Bratislava and FNB, Prague. The comparison has been carried out for three irradiation geometries: single source position, single line and four line motions of the source, and with the effective point of measurement in a plane at 6 mm, 10 mm and 20 mm distance from the source position. The comparison of the MXX measurements and the TPS calculations was evaluated by the commercial IBA Dosimetry software OmniPro I'mRT (1) as the difference between maximum of measured and calculated values and (2) as the maximum difference between the two-dimensional distributions of measured and calculated values. The dose distribution was evaluated by the gamma method with parameters 3 mm and 3%. All differences of comparison of the MXX measurements and TPS calculations were within the range ±10% and the γ -index was less than 1 for 96% (or 97%, respectively) of the dose distribution in the plane at 10 mm distance from the source position. (authors)

  4. Establishment of Ge-doped optical fibres as thermoluminescence dosimeters for brachytherapy

    Energy Technology Data Exchange (ETDEWEB)

    Issa, Fatma, E-mail: f.issa@surrey.ac.uk [Department of Physics, University of Surrey, Guildford, GU2 7XH (United Kingdom); Department of Radiotherapy, Tripoli Medical Centre (TMC), Tripoli (Libya); Abdul Rahman, A.T. [Department of Physics, University of Surrey, Guildford, GU2 7XH (United Kingdom); School of Physics and Material Studies, Faculty of Applied Sciences, Universiti Teknologi MARA Malaysia, Campus of Negeri Sembilan, 72000 Kuala Pilah (Malaysia); Hugtenburg, Richard P. [Department of Medical Physics and Clinical Engineering, Abertawe Bro Morgannwg UHB and School of Medicine, Swansea University, Swansea, SA2 8PP (United Kingdom); Bradley, David A. [Department of Physics, University of Surrey, Guildford, GU2 7XH (United Kingdom); Department of Radiological Sciences, King Saud University, P.O. Box 10219, Riyadh 11432 (Saudi Arabia); Nisbet, Andrew [Department of Physics, University of Surrey, Guildford, GU2 7XH (United Kingdom); Department of Medical Physics, Royal Surrey County Hospital NHS Foundation Trust, Guildford, GU2 7XX (United Kingdom)

    2012-07-15

    This study aims to establish the sensitive, {approx}120 {mu}m high spatial resolution, high dynamic range Ge-doped optical fibres as thermoluminescence (TL) dosimeters for brachytherapy dose distribution. This requires investigation to accommodate sensitivity of detection, both for the possibility of short range dose deposition from beta components as well as gamma/x-mediated dose. In-air measurements are made at distances close to radionuclide sources, evaluating the fall off in dose along the transverse axis of {sup 133}Ba and {sup 60}Co radioactive sources, at distances from 2 mm up to 20 mm from their midpoints. Measurements have been compared with Monte Carlo code DOSRZnrc simulations for photon-mediated dose only, agreement being obtained to within 3% and 1% for the {sup 133}Ba and {sup 60}Co sources, respectively. As such, in both cases it is determined that as intended, beta dose has been filtered out by source encapsulation. - Highlights: Black-Right-Pointing-Pointer We seek to establish Ge-doped optical fibres as TLDs for brachytherapy. Black-Right-Pointing-Pointer Dose was evaluated along the central axis of {sup 133}Ba and {sup 60}Co, at 2 mm-20 mm. Black-Right-Pointing-Pointer We verify values using DOSRZnrc Monte Carlo code simulations. Black-Right-Pointing-Pointer Good agreement is between dose measurements and calculation to within 3% and 1%. Black-Right-Pointing-Pointer Methodology is to be used in obtaining doses around {sup 125}I and {sup 192}Ir sources.

  5. Characteristics of the radiochromic film Gafchromictm EBT3 model for use in brachytherapy; Caracterizacao do filme radiocromico Gafchromictm modelo EBT3 para uso em braquiterapia

    Energy Technology Data Exchange (ETDEWEB)

    Luvizotto, Jessica

    2015-07-01

    Brachytherapy is a radiotherapy treatment modality using radioactive sealed sources within walking distance of the tumor, reducing the risk of applying an unwanted dose to adjacent healthy tissues. For brachytherapy is reliable, it is necessary to establish a dosimetric practices program aimed at determining the optimal dose of radiation for this radiotherapy practice. This paper presents the application of two methodologies for the dosimetry using radiochromic films. Experimental measurements were performed with EBT3 films in phantoms consisting of homogeneous and heterogeneous material (lung, bone and soft tissue) built especially for dose measurements in brachytherapy. The processing and analysis of the resulting images of the experimental procedure were performed with ImageJ software and MATLAB. The results were evaluated from comparisons dose of experimental measurements and simulations obtained by the Monte Carlo method. (author)

  6. AAPM and GEC-ESTRO guidelines for image-guided robotic brachytherapy: Report of Task Group 192

    Energy Technology Data Exchange (ETDEWEB)

    Podder, Tarun K., E-mail: tarun.podder@uhhospitals.org [Department of Radiation Oncology, University Hospitals, Case Western Reserve University, Cleveland, Ohio 44122 (United States); Beaulieu, Luc [Department of Radiation Oncology, Centre Hospitalier Univ de Quebec, Quebec G1R 2J6 (Canada); Caldwell, Barrett [Schools of Industrial Engineering and Aeronautics and Astronautics, Purdue University, West Lafayette, Indiana 47907 (United States); Cormack, Robert A. [Department of Radiation Oncology, Harvard Medical School, Boston, Massachusetts 02115 (United States); Crass, Jostin B. [Department of Radiation Oncology, Vanderbilt University, Nashville, Tennessee 37232 (United States); Dicker, Adam P.; Yu, Yan [Department of Radiation Oncology, Thomas Jefferson University, Philadelphia, Pennsylvania 19107 (United States); Fenster, Aaron [Department of Imaging Research, Robarts Research Institute, London, Ontario N6A 5K8 (Canada); Fichtinger, Gabor [School of Computer Science, Queen’s University, Kingston, Ontario K7L 3N6 (Canada); Meltsner, Michael A. [Philips Radiation Oncology Systems, Fitchburg, Wisconsin 53711 (United States); Moerland, Marinus A. [Department of Radiotherapy, University Medical Center Utrecht, Utrecht, 3508 GA (Netherlands); Nath, Ravinder [Department of Therapeutic Radiology, Yale University School of Medicine, New Haven, Connecticut 06520 (United States); Rivard, Mark J. [Department of Radiation Oncology, Tufts University School of Medicine, Boston, Massachusetts 02111 (United States); Salcudean, Tim [Department of Electrical and Computer Engineering, University of British Columbia, Vancouver, British Columbia V6T 1Z4 (Canada); Song, Danny Y. [Department of Radiation Oncology, Johns Hopkins University School of Medicine, Baltimore, Maryland 21231 (United States); Thomadsen, Bruce R. [Department of Medical Physics, University of Wisconsin, Madison, Wisconsin 53705 (United States)

    2014-10-15

    should mimic the real operating procedure as closely as possible. Additional recommendations on robotic brachytherapy systems include display of the operational state; capability of manual override; documented policies for independent check and data verification; intuitive interface displaying the implantation plan and visualization of needle positions and seed locations relative to the target anatomy; needle insertion in a sequential order; robot–clinician and robot–patient interactions robustness, reliability, and safety while delivering the correct dose at the correct site for the correct patient; avoidance of excessive force on radioactive sources; delivery confirmation of the required number or position of seeds; incorporation of a collision avoidance system; system cleaning, decontamination, and sterilization procedures. These recommendations are applicable to end users and manufacturers of robotic brachytherapy systems.

  7. AAPM and GEC-ESTRO guidelines for image-guided robotic brachytherapy: Report of Task Group 192

    International Nuclear Information System (INIS)

    should mimic the real operating procedure as closely as possible. Additional recommendations on robotic brachytherapy systems include display of the operational state; capability of manual override; documented policies for independent check and data verification; intuitive interface displaying the implantation plan and visualization of needle positions and seed locations relative to the target anatomy; needle insertion in a sequential order; robot–clinician and robot–patient interactions robustness, reliability, and safety while delivering the correct dose at the correct site for the correct patient; avoidance of excessive force on radioactive sources; delivery confirmation of the required number or position of seeds; incorporation of a collision avoidance system; system cleaning, decontamination, and sterilization procedures. These recommendations are applicable to end users and manufacturers of robotic brachytherapy systems

  8. The application of Geant4 simulation code for brachytherapy treatment

    CERN Document Server

    Agostinelli, S; Garelli, S; Paoli, G; Nieminen, P; Pia, M G

    2000-01-01

    Brachytherapy is a radiotherapeutic modality that makes use of radionuclides to deliver a high radiation dose to a well-defined volume while sparing surrounding healthy structures. At the National Institute for Cancer Research of Genova a High Dose Rate remote afterloading system provides Ir(192) endocavitary brachytherapy treatments. We studied the possibility to use the Geant4 Monte Carlo simulation toolkit in brachytherapy for calculation of complex physical parameters, not directly available by experiment al measurements, used in treatment planning dose deposition models.

  9. The mechanical system design of the iridium-192 isotope wire in cervical cancer brachytherapy with medium dose rate

    International Nuclear Information System (INIS)

    In 2010, brachytherapy engineering activities have a purpose to establish a detailed design of the cervical cancer brachytherapy with medium dose rate. The brachytherapy will use an Iridium-92 source with the emiting radiation of 5 to 10 Curies. The source is wrapped in SS-316 capsule and carried by a SS-316 wire having diameter of about 1 mm dan length of 1800 mm. As part of this activity, the preliminary design of the mechanical drive systems for the isotope source has been developed. The technical specifications for the main components of the mechanical drive system have been successfully determined. This is started by studying the concept design, performing calculations, determining technical specifications, and finally defining the main components. From the evaluation, some components were decided: a stepper motor PK264A1-SG10, needle bearing NKI-10/20, spiral tube in SS316-1/8'' with 120 mm in diameter, rubber-based belts with a width of 20 mm, and aluminium drum with a diameter of 100 mm. Not all components could be identified in detail, especially for the components that do not exist in the market place and have to be created ourself. Since the main components have been identified, the detailed design step of the mechanical drive systems for the isotope source can be performed. (author)

  10. Comparison BIPM.RI(I)-K8 of high dose-rate Ir-192 brachytherapy standards for reference air kerma rate of the VSL and the BIPM

    DEFF Research Database (Denmark)

    Alvarez, J.T.; De Pooter, J.A.; Andersen, Claus E.;

    2014-01-01

    An indirect comparison of the standards for reference air kerma rate for 192Ir high dose rate brachytherapy sources of the Dutch Metrology Institute (VSL), The Netherlands, and of the Bureau International des Poids et Mesures (BIPM) was carried out at the VSL in November 2009. The comparison resu...

  11. Assessment of radiation dose for surrounding organs and persons approaching implanted patients upon brachytherapy of prostate cancer with Iridium-192

    International Nuclear Information System (INIS)

    To assess a proper dose for radiation therapy fitting the typical physical characteristics of male Korean bodies, a mathematical phantom was prepared based on standard Korean male measurements. Upon brachytherapy of prostate cancer by implanting 192Ir into the prostate gland (the source organ), the absorbed dose of the prostate gland and surrounding organs and the expected dose of people within the vicinity were assessed. 192Ir, which has been the radionuclide of choice for prostate cancer brachytherapy, was selected for the simulation. It was assumed that 1 Ci of initial radioactivity would be administered. As a result, 1.28 E-02 Gy/Ci was exhibited in the prostate gland of the source organ, and the dose to which persons within the vicinity were exposed was exhibited to be 9.19 E-06 Sv at a distance of 30 cm from the front. (authors)

  12. Development of irradiation support devices for production of brachytherapy seeds

    Energy Technology Data Exchange (ETDEWEB)

    Mattos, Fabio R.; Rostelato, Maria Elisa C.M.; Zeituni, Carlos A.; Souza, Carla D.; Moura, Joao A.; Peleias Junior, Fernando S.; Karan Junior, Dib; Feher, Anselmo; Oliveira, Tiago B.; Benega, Marcos A.G., E-mail: tiagooliveira298@gmail.com, E-mail: mattos.fr@gmail.com, E-mail: elisaros@ipen.br, E-mail: czeituni@ipen.br, E-mail: carladdsouza@yahoo.com.br, E-mail: jamoura@ipen.br, E-mail: ernandopeleias@gmail.com, E-mail: s, E-mail: dib.karan@usp.br, E-mail: afeher@ipen.br, E-mail: marcosagbenega@gmail.com [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil)

    2013-07-01

    Ophthalmic tumors treatment with brachytherapy sources has been widely used as a primary or secondary therapy for non-malignant or malignant tumors, for example, choroid melanoma, and retinoblastoma. Ruthenium-106, Iodine-125, Palladium -103, Gold-198 and Iridium-192, are some radionuclides that can be applied for treatment of ocular tumors. These sources are in small sizes (a few millimeters) and different shapes (rods, wires, disks). To ensure high accuracy during treatment, they are positioned in eye applicators, specially designed to fit on the surface of tumor. The Nuclear and Energy Research Institute (IPEN/CNEN) in a partnership with Paulista Medicine School (UNIFESP) created a project that aims to develop a prototype of Iridium-192 seeds for treatment of eye cancer. This seed consists in a core of Ir -Pt alloy (20%-80%) with a length of 3 mm, to be activated in IPEN's IEA-R1 Reactor, and a titanium capsule sealing the core. It was imperative to develop a sustainer device for irradiation. This piece is used to avoid overlapping of one cores and, therefore, avoiding the 'shadow effect' that does not allow full activation of each core due to the high density. (author)

  13. Water equivalent phantom materials for 192Ir brachytherapy

    Science.gov (United States)

    Schoenfeld, Andreas A.; Harder, Dietrich; Poppe, Björn; Chofor, Ndimofor

    2015-12-01

    Several solid phantom materials have been tested regarding their suitability as water substitutes for dosimetric measurements in brachytherapy with 192Ir as a typical high energy photon emitter. The radial variations of the spectral photon fluence, of the total, primary and scattered photon fluence and of the absorbed dose to water in the transversal plane of the tested cylindrical phantoms surrounding a centric and coaxially arranged Varian GammaMed afterloading 192Ir brachytherapy source were Monte-Carlo simulated in EGSnrc. The degree of water equivalence of a phantom material was evaluated by comparing the radial dose-to-water profile in the phantom material with that in water. The phantom size was varied over a large range since it influences the dose contribution by scattered photons with energies diminished by single and multiple Compton scattering. Phantom axis distances up to 10 cm were considered as clinically relevant. Scattered photons with energies reaching down into the 25 keV region dominate the photon fluence at source distances exceeding 3.5 cm. The tested phantom materials showed significant differences in the degree of water equivalence. In phantoms with radii up to 10 cm, RW1, RW3, Solid Water, HE Solid Water, Virtual Water, Plastic Water DT, and Plastic Water LR phantoms show excellent water equivalence with dose deviations from a water phantom not exceeding 0.8%, while Original Plastic Water (as of 2015), Plastic Water (1995), Blue Water, polyethylene, and polystyrene show deviations up to 2.6%. For larger phantom radii up to 30 cm, the deviations for RW1, RW3, Solid Water, HE Solid Water, Virtual Water, Plastic Water DT, and Plastic Water LR remain below 1.4%, while Original Plastic Water (as of 2015), Plastic Water (1995), Blue Water, polyethylene, and polystyrene produce deviations up to 8.1%. PMMA plays a separate role, with deviations up to 4.3% for radii not exceeding 10 cm, but below 1% for radii up to 30 cm. As suggested by

  14. Water equivalent phantom materials for (192)Ir brachytherapy.

    Science.gov (United States)

    Schoenfeld, Andreas A; Harder, Dietrich; Poppe, Björn; Chofor, Ndimofor

    2015-12-21

    Several solid phantom materials have been tested regarding their suitability as water substitutes for dosimetric measurements in brachytherapy with (192)Ir as a typical high energy photon emitter. The radial variations of the spectral photon fluence, of the total, primary and scattered photon fluence and of the absorbed dose to water in the transversal plane of the tested cylindrical phantoms surrounding a centric and coaxially arranged Varian GammaMed afterloading (192)Ir brachytherapy source were Monte-Carlo simulated in EGSnrc. The degree of water equivalence of a phantom material was evaluated by comparing the radial dose-to-water profile in the phantom material with that in water. The phantom size was varied over a large range since it influences the dose contribution by scattered photons with energies diminished by single and multiple Compton scattering. Phantom axis distances up to 10 cm were considered as clinically relevant. Scattered photons with energies reaching down into the 25 keV region dominate the photon fluence at source distances exceeding 3.5 cm.The tested phantom materials showed significant differences in the degree of water equivalence. In phantoms with radii up to 10 cm, RW1, RW3, Solid Water, HE Solid Water, Virtual Water, Plastic Water DT, and Plastic Water LR phantoms show excellent water equivalence with dose deviations from a water phantom not exceeding 0.8%, while Original Plastic Water (as of 2015), Plastic Water (1995), Blue Water, polyethylene, and polystyrene show deviations up to 2.6%. For larger phantom radii up to 30 cm, the deviations for RW1, RW3, Solid Water, HE Solid Water, Virtual Water, Plastic Water DT, and Plastic Water LR remain below 1.4%, while Original Plastic Water (as of 2015), Plastic Water (1995), Blue Water, polyethylene, and polystyrene produce deviations up to 8.1%. PMMA plays a separate role, with deviations up to 4.3% for radii not exceeding 10 cm, but below 1% for radii up to 30 cm.As suggested

  15. Brachytherapy structural shielding calculations using Monte Carlo generated, monoenergetic data

    International Nuclear Information System (INIS)

    Purpose: To provide a method for calculating the transmission of any broad photon beam with a known energy spectrum in the range of 20–1090 keV, through concrete and lead, based on the superposition of corresponding monoenergetic data obtained from Monte Carlo simulation. Methods: MCNP5 was used to calculate broad photon beam transmission data through varying thickness of lead and concrete, for monoenergetic point sources of energy in the range pertinent to brachytherapy (20–1090 keV, in 10 keV intervals). The three parameter empirical model introduced byArcher et al. [“Diagnostic x-ray shielding design based on an empirical model of photon attenuation,” Health Phys. 44, 507–517 (1983)] was used to describe the transmission curve for each of the 216 energy-material combinations. These three parameters, and hence the transmission curve, for any polyenergetic spectrum can then be obtained by superposition along the lines of Kharrati et al. [“Monte Carlo simulation of x-ray buildup factors of lead and its applications in shielding of diagnostic x-ray facilities,” Med. Phys. 34, 1398–1404 (2007)]. A simple program, incorporating a graphical user interface, was developed to facilitate the superposition of monoenergetic data, the graphical and tabular display of broad photon beam transmission curves, and the calculation of material thickness required for a given transmission from these curves. Results: