WorldWideScience

Sample records for brachytherapy d-shaped applicators

  1. Directional interstitial brachytherapy from simulation to application

    Science.gov (United States)

    Lin, Liyong

    Organs at risk (OAR) are sometimes adjacent to or embedded in or overlap with the clinical target volume (CTV) to be treated. The purpose of this PhD study is to develop directionally low energy gamma-emitting interstitial brachytherapy sources. These sources can be applied between OAR to selectively reduce hot spots in the OARs and normal tissues. The reduction of dose over undesired regions can expand patient eligibility or reduce toxicities for the treatment by conventional interstitial brachytherapy. This study covers the development of a directional source from design optimization to construction of the first prototype source. The Monte Carlo code MCNP was used to simulate the radiation transport for the designs of directional sources. We have made a special construction kit to assemble radioactive and gold-shield components precisely into D-shaped titanium containers of the first directional source. Directional sources have a similar dose distribution as conventional sources on the treated side but greatly reduced dose on the shielded side, with a sharp dose gradient between them. A three-dimensional dose deposition kernel for the 125I directional source has been calculated. Treatment plans can use both directional and conventional 125I sources at the same source strength for low-dose-rate (LDR) implants to optimize the dose distributions. For prostate tumors, directional 125I LDR brachytherapy can potentially reduce genitourinary and gastrointestinal toxicities and improve potency preservation for low risk patients. The combination of better dose distribution of directional implants and better therapeutic ratio between tumor response and late reactions enables a novel temporary LDR treatment, as opposed to permanent or high-dose-rate (HDR) brachytherapy for the intermediate risk T2b and high risk T2c tumors. Supplemental external-beam treatments can be shortened with a better brachytherapy boost for T3 tumors. In conclusion, we have successfully finished the

  2. Performance profiling for brachytherapy applications

    Science.gov (United States)

    Choi, Wonqook; Cho, Kihyeon; Yeo, Insung

    2018-05-01

    In many physics applications, a significant amount of software (e.g. R, ROOT and Geant4) is developed on novel computing architectures, and much effort is expended to ensure the software is efficient in terms of central processing unit (CPU) time and memory usage. Profiling tools are used during the evaluation process to evaluate the efficiency; however, few such tools are able to accommodate low-energy physics regions. To address this limitation, we developed a low-energy physics profiling system in Geant4 to profile the CPU time and memory of software applications in brachytherapy applications. This paper describes and evaluates specific models that are applied to brachytherapy applications in Geant4, such as QGSP_BIC_LIV, QGSP_BIC_EMZ, and QGSP_BIC_EMY. The physics range in this tool allows it to be used to generate low energy profiles in brachytherapy applications. This was a limitation in previous studies, which caused us to develop a new profiling tool that supports profiling in the MeV range, in contrast to the TeV range that is supported by existing high-energy profiling tools. In order to easily compare the profiling results between low-energy and high-energy modes, we employed the same software architecture as that in the SimpliCarlo tool developed at the Fermilab National Accelerator Laboratory (FNAL) for the Large Hadron Collider (LHC). The results show that the newly developed profiling system for low-energy physics (less than MeV) complements the current profiling system used for high-energy physics (greater than TeV) applications.

  3. Refractive Index Sensing with D-Shaped Plastic Optical Fibers for Chemical and Biochemical Applications.

    Science.gov (United States)

    Sequeira, Filipa; Duarte, Daniel; Bilro, Lúcia; Rudnitskaya, Alisa; Pesavento, Maria; Zeni, Luigi; Cennamo, Nunzio

    2016-12-13

    We report the optimization of the length of a D-shaped plastic optical fiber (POF) sensor for refractive index (RI) sensing from a numerical and experimental point of view. The sensing principle is based on total internal reflection (TIR). POFs with 1 mm in diameter were embedded in grooves, realized in planar supports with different lengths, and polished to remove the cladding and part of the core. All D-shaped POF sensors were tested using aqueous medium with different refractive indices (from 1.332 to 1.471) through intensity-based configuration. Results showed two different responses. Considering the refractive index (RI) range (1.33-1.39), the sensitivity and the resolution of the sensor were strongly dependent on the sensing region length. The highest sensitivity (resolution of 6.48 × 10 -3 refractive index units, RIU) was obtained with 6 cm sensing length. In the RI range (1.41-1.47), the length of the sensing region was not a critical aspect to obtain the best resolution. These results enable the application of this optical platform for chemical and biochemical evanescent field sensing. The sensor production procedure is very simple, fast, and low-cost.

  4. Refractive Index Sensing with D-Shaped Plastic Optical Fibers for Chemical and Biochemical Applications

    Directory of Open Access Journals (Sweden)

    Filipa Sequeira

    2016-12-01

    Full Text Available We report the optimization of the length of a D-shaped plastic optical fiber (POF sensor for refractive index (RI sensing from a numerical and experimental point of view. The sensing principle is based on total internal reflection (TIR. POFs with 1 mm in diameter were embedded in grooves, realized in planar supports with different lengths, and polished to remove the cladding and part of the core. All D-shaped POF sensors were tested using aqueous medium with different refractive indices (from 1.332 to 1.471 through intensity-based configuration. Results showed two different responses. Considering the refractive index (RI range (1.33–1.39, the sensitivity and the resolution of the sensor were strongly dependent on the sensing region length. The highest sensitivity (resolution of 6.48 × 10−3 refractive index units, RIU was obtained with 6 cm sensing length. In the RI range (1.41–1.47, the length of the sensing region was not a critical aspect to obtain the best resolution. These results enable the application of this optical platform for chemical and biochemical evanescent field sensing. The sensor production procedure is very simple, fast, and low-cost.

  5. Radiochromic dye film studies for brachytherapy applications

    International Nuclear Information System (INIS)

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

  6. Brachytherapy

    Science.gov (United States)

    ... the use of a type of energy, called ionizing radiation, to kill cancer cells and shrink tumors. External ... In all cases of brachytherapy, the source of radiation is encapsulated ... non-radioactive metallic capsule. This prevents the radioactive materials ...

  7. Dose assessment for brachytherapy with Henschke applicator

    International Nuclear Information System (INIS)

    Yu, Pei-Chieh; Chao, Tsi-Chian; Tung, Chuan-Jong; Wu, Ching-Jung; Lee, Chung-Chi

    2011-01-01

    Dose perturbation caused by the Henschke applicator is a major concern for the brachytherapy planning system (BPS) in recent years. To investigate dose impact owing to neglect of the metal shielding effect, Monte Carlo (MC) simulation, BPS calculation, and film measurement have been performed for dose assessment in a water phantom. Additionally, a cylindrical air cavity representing the rectum was added into the MC simulation to study its effect on dose distribution. Monte Carlo N-Particle Transport Code (MCNP) was used in this study to simulate the dose distribution using a mesh tally. This Monte Carlo simulation has been validated using the TG-43 data in a previous report. For the measurement, the Henschke applicator was placed in a specially-designed phantom, and Gafchromic films were inserted in the center plane for 2D dose assessment. Isodose distributions with and without the Henschke applicator by the MC simulation show significant deviation from those by the BPS. For MC simulation, the isodose curves shrank more significantly when the metal applicator was applied. For the impact of the added air cavity, the results indicate that it is hard to distinguish between with and without the cavity. Thus, the rectum cavity has little impact on the dose distribution around the Henschke applicator.

  8. Accurate localization of intracavitary brachytherapy applicators from 3D CT imaging studies

    International Nuclear Information System (INIS)

    Lerma, F.A.; Williamson, J.F.

    2002-01-01

    Purpose: To present an accurate method to identify the positions and orientations of intracavitary (ICT) brachytherapy applicators imaged in 3D CT scans, in support of Monte Carlo photon-transport simulations, enabling accurate dose modeling in the presence of applicator shielding and interapplicator attenuation. Materials and methods: The method consists of finding the transformation that maximizes the coincidence between the known 3D shapes of each applicator component (colpostats and tandem) with the volume defined by contours of the corresponding surface on each CT slice. We use this technique to localize Fletcher-Suit CT-compatible applicators for three cervix cancer patients using post-implant CT examinations (3 mm slice thickness and separation). Dose distributions in 1-to-1 registration with the underlying CT anatomy are derived from 3D Monte Carlo photon-transport simulations incorporating each applicator's internal geometry (source encapsulation, high-density shields, and applicator body) oriented in relation to the dose matrix according to the measured localization transformations. The precision and accuracy of our localization method are assessed using CT scans, in which the positions and orientations of dense rods and spheres (in a precision-machined phantom) were measured at various orientations relative to the gantry. Results: Using this method, we register 3D Monte Carlo dose calculations directly onto post insertion patient CT studies. Using CT studies of a precisely machined phantom, the absolute accuracy of the method was found to be ±0.2 mm in plane, and ±0.3 mm in the axial direction while its precision was ±0.2 mm in plane, and ±0.2 mm axially. Conclusion: We have developed a novel, and accurate technique to localize intracavitary brachytherapy applicators in 3D CT imaging studies, which supports 3D dose planning involving detailed 3D Monte Carlo dose calculations, modeling source positions, shielding and interapplicator shielding

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

    International Nuclear Information System (INIS)

    1996-01-01

    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

  10. Cervical cancer. Application of MR imaging in brachytherapy

    International Nuclear Information System (INIS)

    Ebe, Kazuyu; Matsunaga, Naofumi

    1996-01-01

    For the purpose of application of MRI in arrangement of brachytherapy of cervical cancer, a method was proposed to see the radiation doses in surrounding tissues by superimposing the dose distribution pattern of the radiation source on the MR image. The applicator for the source was filled with water to get its T2-weighted image and was inserted in the patients. The MRI apparatus was Siemens Magnetom Vision (1.5T) with phased array coil. T2-weighted sagittal and coronary images were taken by turbospin echo and HASTE methods. The section thickness was 5 mm. The dose distribution pattern was superimposed on the frontal and lateral images by Siemens Mevaplan to see the doses in surrounding tissues. In 4 patients, it was possible to estimate the radiation dose in the posterior wall of bladder, anterior wall of rectum and urinary duct. The method is promising for arranging brachytherapy of cervical cancer. (K.H.)

  11. A new afterloading applicator for primary brachytherapy of endometrial cancer

    International Nuclear Information System (INIS)

    Bauer, M.; Schulz-Wendtland, R.

    1993-01-01

    The authors describe and have used a new afterloading applicator in six patients for primary radiation therapy of endometrial cancer. The first introduction of the applicator was done under general anaesthesia. Dilating the cervical canal to Heger 9 made insertion easier. Prior to application it is advisable to probe the lumen of the uterine cavity with a tube or curette to estimate how far the applicator must be spread open. For brachytherapy it is advantageous to remove necrotic tumour portions. This requires experienced hands to avoid perforation of the uterus. The new afterloading applicator is easy to use, and permits direct contact between the six tubes and the tumour. In conjunction with careful planning with the help of MRI, it provides an optimal system for the treatment of endometrial cancer. (Author)

  12. Density-Based 3D Shape Descriptors

    Directory of Open Access Journals (Sweden)

    Schmitt Francis

    2007-01-01

    Full Text Available We propose a novel probabilistic framework for the extraction of density-based 3D shape descriptors using kernel density estimation. Our descriptors are derived from the probability density functions (pdf of local surface features characterizing the 3D object geometry. Assuming that the shape of the 3D object is represented as a mesh consisting of triangles with arbitrary size and shape, we provide efficient means to approximate the moments of geometric features on a triangle basis. Our framework produces a number of 3D shape descriptors that prove to be quite discriminative in retrieval applications. We test our descriptors and compare them with several other histogram-based methods on two 3D model databases, Princeton Shape Benchmark and Sculpteur, which are fundamentally different in semantic content and mesh quality. Experimental results show that our methodology not only improves the performance of existing descriptors, but also provides a rigorous framework to advance and to test new ones.

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

    International Nuclear Information System (INIS)

    1992-01-01

    In addition to a basic guide to the principles of the production of ionizing radiation and to methods of radiation protection and dosimetry, this booklet includes information about radiation protection procedures for brachytherapy

  14. GGEMS-Brachy: GPU GEant4-based Monte Carlo simulation for brachytherapy applications

    International Nuclear Information System (INIS)

    Lemaréchal, Yannick; Bert, Julien; Schick, Ulrike; Pradier, Olivier; Garcia, Marie-Paule; Boussion, Nicolas; Visvikis, Dimitris; Falconnet, Claire; Després, Philippe; Valeri, Antoine

    2015-01-01

    In brachytherapy, plans are routinely calculated using the AAPM TG43 formalism which considers the patient as a simple water object. An accurate modeling of the physical processes considering patient heterogeneity using Monte Carlo simulation (MCS) methods is currently too time-consuming and computationally demanding to be routinely used. In this work we implemented and evaluated an accurate and fast MCS on Graphics Processing Units (GPU) for brachytherapy low dose rate (LDR) applications. A previously proposed Geant4 based MCS framework implemented on GPU (GGEMS) was extended to include a hybrid GPU navigator, allowing navigation within voxelized patient specific images and analytically modeled 125 I seeds used in LDR brachytherapy. In addition, dose scoring based on track length estimator including uncertainty calculations was incorporated. The implemented GGEMS-brachy platform was validated using a comparison with Geant4 simulations and reference datasets. Finally, a comparative dosimetry study based on the current clinical standard (TG43) and the proposed platform was performed on twelve prostate cancer patients undergoing LDR brachytherapy. Considering patient 3D CT volumes of 400  × 250  × 65 voxels and an average of 58 implanted seeds, the mean patient dosimetry study run time for a 2% dose uncertainty was 9.35 s (≈500 ms 10 −6 simulated particles) and 2.5 s when using one and four GPUs, respectively. The performance of the proposed GGEMS-brachy platform allows envisaging the use of Monte Carlo simulation based dosimetry studies in brachytherapy compatible with clinical practice. Although the proposed platform was evaluated for prostate cancer, it is equally applicable to other LDR brachytherapy clinical applications. Future extensions will allow its application in high dose rate brachytherapy applications. (paper)

  15. GGEMS-Brachy: GPU GEant4-based Monte Carlo simulation for brachytherapy applications

    Science.gov (United States)

    Lemaréchal, Yannick; Bert, Julien; Falconnet, Claire; Després, Philippe; Valeri, Antoine; Schick, Ulrike; Pradier, Olivier; Garcia, Marie-Paule; Boussion, Nicolas; Visvikis, Dimitris

    2015-07-01

    In brachytherapy, plans are routinely calculated using the AAPM TG43 formalism which considers the patient as a simple water object. An accurate modeling of the physical processes considering patient heterogeneity using Monte Carlo simulation (MCS) methods is currently too time-consuming and computationally demanding to be routinely used. In this work we implemented and evaluated an accurate and fast MCS on Graphics Processing Units (GPU) for brachytherapy low dose rate (LDR) applications. A previously proposed Geant4 based MCS framework implemented on GPU (GGEMS) was extended to include a hybrid GPU navigator, allowing navigation within voxelized patient specific images and analytically modeled 125I seeds used in LDR brachytherapy. In addition, dose scoring based on track length estimator including uncertainty calculations was incorporated. The implemented GGEMS-brachy platform was validated using a comparison with Geant4 simulations and reference datasets. Finally, a comparative dosimetry study based on the current clinical standard (TG43) and the proposed platform was performed on twelve prostate cancer patients undergoing LDR brachytherapy. Considering patient 3D CT volumes of 400  × 250  × 65 voxels and an average of 58 implanted seeds, the mean patient dosimetry study run time for a 2% dose uncertainty was 9.35 s (≈500 ms 10-6 simulated particles) and 2.5 s when using one and four GPUs, respectively. The performance of the proposed GGEMS-brachy platform allows envisaging the use of Monte Carlo simulation based dosimetry studies in brachytherapy compatible with clinical practice. Although the proposed platform was evaluated for prostate cancer, it is equally applicable to other LDR brachytherapy clinical applications. Future extensions will allow its application in high dose rate brachytherapy applications.

  16. Sci-Thur PM – Brachytherapy 06: 3D Printed Surface Applicators for High Dose Rate Brachytherapy

    Energy Technology Data Exchange (ETDEWEB)

    Clarke, Scott; Yewondwossen, Mammo; Robar, James [Dalhousie University, Nova Scotia Cancer Centre, Capital District Health Authority (Canada)

    2016-08-15

    Purpose: The purpose of this work is to develop a new applicator for administering high dose rate (HDR) brachytherapy using 3D printing technology. Primary advantages of using a 3D printed applicator will be to offer a more streamlined approach for therapists and patients while achieving better conformity, reproducibility, and patient specific applicators. Methods: A phantom study was conducted to measure the effectiveness of a 3D printed surface applicator by analyzing tumours on three locations of the body: the foot, nose, and scalp. The applicator was designed using Eclipse and further modified using Blender to create the catheter tunnels before being printed on a Lulzbot Taz 5 3D printer. A radiation plan was made using Oncentra Brachytherapy for a control treatment option using Freiburg Flaps and one with the novel method of a 3D printed applicator. A comparative analysis was made using D90, D100, V100, V150, and V200 Results: The 3D printed applicator showed comparable dose coverage with significant improvements on highly irregular surfaces when analyzed against a plan made using Freiburg Flaps. Although both plans exhibited complete tumour coverage, the 3D applicator showed improvements in D90 and V150 and the 3D applicator had a dose homogeneity index (DHI) of 0.99 compared to a DHI of 0.97 for the control. Therapist prep time also dropped significantly due to the lack of need for a thermoplastic mesh. Conclusions: 3D printed applicators for treatment of superficial sites proved to offer more patient convenience, less prep time, better conformity and tighter margins.

  17. Sci-Thur PM – Brachytherapy 06: 3D Printed Surface Applicators for High Dose Rate Brachytherapy

    International Nuclear Information System (INIS)

    Clarke, Scott; Yewondwossen, Mammo; Robar, James

    2016-01-01

    Purpose: The purpose of this work is to develop a new applicator for administering high dose rate (HDR) brachytherapy using 3D printing technology. Primary advantages of using a 3D printed applicator will be to offer a more streamlined approach for therapists and patients while achieving better conformity, reproducibility, and patient specific applicators. Methods: A phantom study was conducted to measure the effectiveness of a 3D printed surface applicator by analyzing tumours on three locations of the body: the foot, nose, and scalp. The applicator was designed using Eclipse and further modified using Blender to create the catheter tunnels before being printed on a Lulzbot Taz 5 3D printer. A radiation plan was made using Oncentra Brachytherapy for a control treatment option using Freiburg Flaps and one with the novel method of a 3D printed applicator. A comparative analysis was made using D90, D100, V100, V150, and V200 Results: The 3D printed applicator showed comparable dose coverage with significant improvements on highly irregular surfaces when analyzed against a plan made using Freiburg Flaps. Although both plans exhibited complete tumour coverage, the 3D applicator showed improvements in D90 and V150 and the 3D applicator had a dose homogeneity index (DHI) of 0.99 compared to a DHI of 0.97 for the control. Therapist prep time also dropped significantly due to the lack of need for a thermoplastic mesh. Conclusions: 3D printed applicators for treatment of superficial sites proved to offer more patient convenience, less prep time, better conformity and tighter margins.

  18. A new applicator design for endocavitary brachytherapy of cancer in the nasopharynx

    International Nuclear Information System (INIS)

    Levendag, Peter C.; Peters, Rob; Meeuwis, Cees A.; Visch, Leo L.; Sipkema, Dick; Pan, Connie de; Schmitz, Paul I.M.

    1997-01-01

    Introduction: In attempting to improve local tumor control by higher doses of radiation, there has been a resurgence of interest in the implementation of brachytherapy in the management of primary and recurrent cancers of the nasopharynx. Brachytherapy with its steep dose fall-off is of particular interest because of the proximity of critical dose limiting structures. Recent developments in brachytherapy, such as the introduction of pulsed-dose-rate and high-dose-rate computerized afterloaders, have encouraged further evolution of brachytherapy techniques. Materials and methods: We have designed an inexpensive, re-usable and flexible silicone applicator, tailored to the shape of the soft tissues of the nasopharynx, which can be used with either low-dose-rate brachytherapy or high (pulsed)-dose-rate remote controlled afterloaders. Results and conclusions: This Rotterdam nasopharynx applicator proved to be easy to introduce, patient friendly and can remain in situ for the duration of the treatment (2-6 days). The design, technique of application and the first consecutive 5 years of clinical experience in using this applicator are presented

  19. A Monte Carlo dosimetry study using Henschke applicator for cervical brachytherapy

    International Nuclear Information System (INIS)

    Yu, Pei-Chieh; Chao, Tsi-Chian; Lee, Chung-Chi; Wu, Ching-Jung; Tung, Chuan-Jong

    2010-01-01

    In recent years the Henschke applicator has been widely used for gynecologic patients treated by brachytherapy in Taiwan. However, the commercial brachytherapy planning system did not properly evaluate the dose perturbation caused by the Henschke applicator. Since the European Society for Therapeutic Radiology and Oncology advised that the effect of source shielding should be incorporated into the brachytherapy planning system, it required calculation and comparison of the dose distribution around the applicator. This study used the Monte Carlo MCNP code to simulate the dose distribution in a water phantom that contained the Henschke applicator with one tandem and two ovoids. Three dwell positions of a high dose rate 192 Ir source were simulated by including and excluding the applicator. The mesh tally option of the MCNP was applied to facilitate the calculation of a large number of tallies in the phantom. The voxel size effect and the charge particle equilibrium were studied by comparing the results calculated with different tally options. The calculated results showed that the brachytherapy planning system overestimated the rectal dose and that the shielding material in the applicator contributed more than 40% to the rectal dose.

  20. Experience of the first application of HDR brachytherapy in nasopharynx

    International Nuclear Information System (INIS)

    Vega Hernandez, Manuel I.; Alfonso Laguardia, Rodolfo; Silvestre Patallo, Ileana; Roca Muchuli, Carlos; Garcia Heredia, Gilda

    2006-01-01

    A research was made by applying boost on the area of the nasopharynx relapse with high dose rate (HDR) in a diagnosis of nasopharynx carcinoma previously treated with telecobalt therapy, at a dose of 70 Gy. There was persistence of the injury. Three sessions were planned, with consecutive fractions of 6.5 Gy in 15 days, with optimization, using a personal mould of autopolymerizable acrylic. The successful possibility to apply the high rate modern brachytherapy was reaffirmed, as a treatment complementary to teletherapy in case of persistence or relapse. A Micro Selectron HDR equipment was used

  1. Dosimetric study of surface applicators of HDR brachytherapy GammaMed Plus equipment

    International Nuclear Information System (INIS)

    Reyes-Rivera, E.; Sosa, M.; Reyes, U.; Jesús Bernal-Alvarado, José de; Córdova, T.; Gil-Villegas, A.; Monzón, E.

    2014-01-01

    The cone type surface applicators used in HDR brachytherapy for treatment of small skin lesions are an alternative to be used with both electron beams and orthovoltage X-ray equipment. For a good treatment planning is necessary to know the dose distribution of these applicators, which can be obtained by experimental measurement and Monte Carlo simulation as well. In this study the dose distribution of surface applicators of 3 and 3.5 cm diameter, respectively of HDR brachytherapy GammaMed Plus equipment has been estimated using the Monte Carlo method, MCNP code. The applicators simulated were placed on the surface of a water phantom of 20 × 20 × 20 cm and the dose was calculated at depths from 0 to 3 cm with increments of 0.25 mm. The dose profiles obtained at depth show the expected gradients for surface therapy

  2. Dosimetric study of surface applicators of HDR brachytherapy GammaMed Plus equipment

    Energy Technology Data Exchange (ETDEWEB)

    Reyes-Rivera, E., E-mail: eric-1985@fisica.ugto.mx, E-mail: modesto@fisica.ugto.mx, E-mail: uvaldoreyes@fisica.ugto.mx; Sosa, M., E-mail: eric-1985@fisica.ugto.mx, E-mail: modesto@fisica.ugto.mx, E-mail: uvaldoreyes@fisica.ugto.mx; Reyes, U., E-mail: eric-1985@fisica.ugto.mx, E-mail: modesto@fisica.ugto.mx, E-mail: uvaldoreyes@fisica.ugto.mx; Jesús Bernal-Alvarado, José de, E-mail: bernal@fisica.ugto.mx, E-mail: theo@fisica.ugto.mx, E-mail: gil@fisica.ugto.mx; Córdova, T., E-mail: bernal@fisica.ugto.mx, E-mail: theo@fisica.ugto.mx, E-mail: gil@fisica.ugto.mx; Gil-Villegas, A., E-mail: bernal@fisica.ugto.mx, E-mail: theo@fisica.ugto.mx, E-mail: gil@fisica.ugto.mx [División de Ciencias e Ingenierías, Universidad de Guanajuato, 37150 León, Gto. (Mexico); Monzón, E., E-mail: emonzon@imss.gob.mx [Unidad de Alta Especialidad No.1, Instituto Mexicano del Seguro Social, Léon, Gto. (Mexico)

    2014-11-07

    The cone type surface applicators used in HDR brachytherapy for treatment of small skin lesions are an alternative to be used with both electron beams and orthovoltage X-ray equipment. For a good treatment planning is necessary to know the dose distribution of these applicators, which can be obtained by experimental measurement and Monte Carlo simulation as well. In this study the dose distribution of surface applicators of 3 and 3.5 cm diameter, respectively of HDR brachytherapy GammaMed Plus equipment has been estimated using the Monte Carlo method, MCNP code. The applicators simulated were placed on the surface of a water phantom of 20 × 20 × 20 cm and the dose was calculated at depths from 0 to 3 cm with increments of 0.25 mm. The dose profiles obtained at depth show the expected gradients for surface therapy.

  3. Custom-made micro applicators for high-dose-rate brachytherapy treatment of chronic psoriasis

    Directory of Open Access Journals (Sweden)

    Ivan M. Buzurovic

    2017-06-01

    Full Text Available Purpose: In this study, we present the treatment of the psoriatic nail beds of patients refractory to standard therapies using high-dose-rate (HDR brachytherapy. The custom-made micro applicators (CMMA were designed and constructed for radiation dose delivery to small curvy targets with complicated topology. The role of the HDR brachytherapy treatment was to stimulate the T cells for an increased immune response. Material and methods: The patient diagnosed with psoriatic nail beds refractory to standard therapies received monthly subunguinal injections that caused significant pain and discomfort in both hands. The clinical target was defined as the length from the fingertip to the distal interphalangeal joint. For the accurate and reproducible setup in the multi-fractional treatment delivery, the CMMAs were designed. Five needles were embedded into the dense plastic mesh and covered with 5 mm bolus material for each micro applicator. Five CMMAs were designed, resulting in the usage of 25 catheters in total. Results: The prescription dose was planned to the depth of the anterior surface of the distal phalanx, allowing for the sparing of the surrounding tissue. The total number of the active dwell positions was 145 with step size of 5 mm. The total treatment time was 115 seconds with a 7.36 Ci activity of the 192Ir source. The treatment resulted in good pain control. The patient did not require further injections to the nail bed. After this initial treatment, additional two patients with similar symptoms received HDR brachytherapy. The treatment outcome was favorable in all cases. Conclusions : The first HDR brachytherapy treatment of psoriasis of the nail bed is presented. The initial experience revealed that brachytherapy treatment was well-tolerated and resulted in adequate control of the disease. A larger cohort of patients will be required for additional conclusions related to the long-term clinical benefits.

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

    International Nuclear Information System (INIS)

    Sinha, Neeharika; Cifter, Gizem; Sajo, Erno; Kumar, Rajiv; Sridhar, Srinivas; Nguyen, Paul L.; Cormack, Robert A.; Makrigiorgos, G. Mike; Ngwa, Wilfred

    2015-01-01

    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

  5. 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

  6. The use of tetrahedral mesh geometries in Monte Carlo simulation of applicator based brachytherapy dose distributions

    International Nuclear Information System (INIS)

    Fonseca, Gabriel Paiva; Yoriyaz, Hélio; Landry, Guillaume; White, Shane; Reniers, Brigitte; Verhaegen, Frank; D’Amours, Michel; Beaulieu, Luc

    2014-01-01

    Accounting for brachytherapy applicator attenuation is part of the recommendations from the recent report of AAPM Task Group 186. To do so, model based dose calculation algorithms require accurate modelling of the applicator geometry. This can be non-trivial in the case of irregularly shaped applicators such as the Fletcher Williamson gynaecological applicator or balloon applicators with possibly irregular shapes employed in accelerated partial breast irradiation (APBI) performed using electronic brachytherapy sources (EBS). While many of these applicators can be modelled using constructive solid geometry (CSG), the latter may be difficult and time-consuming. Alternatively, these complex geometries can be modelled using tessellated geometries such as tetrahedral meshes (mesh geometries (MG)). Recent versions of Monte Carlo (MC) codes Geant4 and MCNP6 allow for the use of MG. The goal of this work was to model a series of applicators relevant to brachytherapy using MG. Applicators designed for 192 Ir sources and 50 kV EBS were studied; a shielded vaginal applicator, a shielded Fletcher Williamson applicator and an APBI balloon applicator. All applicators were modelled in Geant4 and MCNP6 using MG and CSG for dose calculations. CSG derived dose distributions were considered as reference and used to validate MG models by comparing dose distribution ratios. In general agreement within 1% for the dose calculations was observed for all applicators between MG and CSG and between codes when considering volumes inside the 25% isodose surface. When compared to CSG, MG required longer computation times by a factor of at least 2 for MC simulations using the same code. MCNP6 calculation times were more than ten times shorter than Geant4 in some cases. In conclusion we presented methods allowing for high fidelity modelling with results equivalent to CSG. To the best of our knowledge MG offers the most accurate representation of an irregular APBI balloon applicator. (paper)

  7. Brachytherapy at the Institut Gustave-Roussy: Personalized vaginal mould applicator: technical modification and improvement

    International Nuclear Information System (INIS)

    Albano, M.; Dumas, I.; Haie-Meder, C.

    2008-01-01

    Brachytherapy plays an important role in the treatment of patients with gynaecological cancers. At the Institut Gustave-Roussy, the technique of vaginal mould applicator has been used for decades. This technique allows a personalized tailored irradiation, integrating tumour shape, size and extension and vaginal anatomy. Vaginal expansion reduces the dose to the vaginal mucosa and to the organs at risk. We report a modification of the material used for vaginal mould manufacture. The advantages of the new material are a lighter weight, and transparency allowing a better accuracy in the placement of catheters for radioactive sources. This material is applicable for low dose-rate, pulse dose-rate and high dose-rate brachytherapy. Since 2001, more than 700 vaginal moulds have been manufactured with this new approach without any intolerance. (authors)

  8. A novel system for commissioning brachytherapy applicators: example of a ring applicator

    Science.gov (United States)

    Fonseca, Gabriel P.; Van den Bosch, Michiel R.; Voncken, Robert; Podesta, Mark; Verhaegen, Frank

    2017-11-01

    A novel system was developed to improve commissioning and quality assurance of brachytherapy applicators used in high dose rate (HDR). It employs an imaging panel to create reference images and to measure dwell times and dwell positions. As an example: two ring applicators of the same model were evaluated. An applicator was placed on the surface of an imaging panel and a HDR 192Ir source was positioned in an imaging channel above the panel to generate an image of the applicator, using the gamma photons of the brachytherapy source. The applicator projection image was overlaid with the images acquired by capturing the gamma photons emitted by the source dwelling inside the applicator. We verified 0.1, 0.2, 0.5 and 1.0 cm interdwell distances for different offsets, applicator inclinations and transfer tube curvatures. The data analysis was performed using in-house developed software capable of processing the data in real time, defining catheters and creating movies recording the irradiation procedure. One applicator showed up to 0.3 cm difference from the expected position for a specific dwell position. The problem appeared intermittently. The standard deviations of the remaining dwell positions (40 measurements) were less than 0.05 cm. The second ring applicator had a similar reproducibility with absolute coordinate differences from expected values ranging from  -0.10 up to 0.18 cm. The curvature of the transfer tube can lead to differences larger than 0.1 cm whilst the inclination of the applicator showed a negligible effect. The proposed method allows the verification of all steps of the irradiation, providing accurate information about dwell positions and dwell times. It allows the verification of small interdwell positions (⩽0.1 cm) and reduces measurement time. In addition, no additional radiation source is necessary since the HDR 192Ir source is used to generate an image of the applicator.

  9. Multilayer conformal applicator for microwave heating and brachytherapy treatment of superficial tissue disease.

    Science.gov (United States)

    Juang, T; Stauffer, P R; Neuman, D G; Schlorff, J L

    2006-11-01

    The purpose of this study was to construct and perform preliminary functionality evaluations of a multilayer conformal applicator with provisions for thermal monitoring, tight conformity and simultaneous microwave heating and brachytherapy treatment of large-area contoured surfaces. The multilayer conformal applicator consists of thermal monitoring catheters for fibre-optic monitoring of skin temperatures, a waterbolus, a PCB microwave antenna array, a dielectric spacer for brachytherapy considerations, brachytherapy catheters for delivering HDR radiation and an inflatable air bladder for improving conformity to contoured surfaces. The applicator also includes an elastic attachment structure to hold the applicator securely in place on the patient. The conformity of the applicator to irregular surfaces was evaluated through CT imaging of the applicator fitted onto a life-sized human torso phantom. The fluid flow dynamics of the waterbolus, which impact the effectiveness of temperature control, were evaluated with thermometry during a 19 degrees C step change temperature of the circulating water. CT imaging showed improved conformity to the torso phantom surface following the application of gentle inward pressure from inflating the outer air bladder. Only a small number of 1-5 mm sized air gaps separated the conformal applicator and tissue surface. Thermometry testing of the bolus fluid flow dynamics demonstrated temperature uniformity within +/-0.82 degrees C across a 19 x 34 x 0.6 cm area bolus and +/-0.85 degrees C across a large 42 x 32 x 0.6 cm area bolus. CT scans of the applicator confirmed that the applicator conforms well to complex body contours and should maintain good conformity and positional stability even when worn on a mobile patient. Thermometry testing of two different waterbolus geometries demonstrated that uniform circulation and temperature control can be maintained throughout large, complex bolus shapes.

  10. External beam techniques to boost cervical cancer when brachytherapy is not an option—theories and applications

    Science.gov (United States)

    Kilic, Sarah; Khan, Atif J.; Beriwal, Sushil; Small, William

    2017-01-01

    The management of locally advanced cervical cancer relies on brachytherapy (BT) as an integral part of the radiotherapy delivery armamentarium. Occasionally, intracavitary BT is neither possible nor available. In these circumstances, post-external beam radiotherapy (EBRT) interstitial brachytherapy and/or hysterectomy may represent viable options that must be adequately executed in a timely manner. However, if these options are not applicable due to patient related or facility related reasons, a formal contingency plan should be in place. Innovative EBRT techniques such as intensity modulated and stereotactic radiotherapy may be considered for patients unable to undergo brachytherapy. Relying on provocative arguments and recent data, this review explores the rationale for and limitations of non-brachytherapy substitutes in that setting aiming to establish a formal process for the optimal execution of this alternative plan. PMID:28603722

  11. Modeling a Hypothetical 170Tm Source for Brachytherapy Applications

    International Nuclear Information System (INIS)

    Enger, Shirin A.; D'Amours, Michel; Beaulieu, Luc

    2011-01-01

    Purpose: To perform absorbed dose calculations based on Monte Carlo simulations for a hypothetical 170 Tm source and to investigate the influence of encapsulating material on the energy spectrum of the emitted electrons and photons. Methods: GEANT4 Monte Carlo code version 9.2 patch 2 was used to simulate the decay process of 170 Tm and to calculate the absorbed dose distribution using the GEANT4 Penelope physics models. A hypothetical 170 Tm source based on the Flexisource brachytherapy design with the active core set as a pure thulium cylinder (length 3.5 mm and diameter 0.6 mm) and different cylindrical source encapsulations (length 5 mm and thickness 0.125 mm) constructed of titanium, stainless-steel, gold, or platinum were simulated. The radial dose function for the line source approximation was calculated following the TG-43U1 formalism for the stainless-steel encapsulation. Results: For the titanium and stainless-steel encapsulation, 94% of the total bremsstrahlung is produced inside the core, 4.8 and 5.5% in titanium and stainless-steel capsules, respectively, and less than 1% in water. For the gold capsule, 85% is produced inside the core, 14.2% inside the gold capsule, and a negligible amount ( 170 Tm source is primarily a bremsstrahlung source, with the majority of bremsstrahlung photons being generated in the source core and experiencing little attenuation in the source encapsulation. Electrons are efficiently absorbed by the gold and platinum encapsulations. However, for the stainless-steel capsule (or other lower Z encapsulations) electrons will escape. The dose from these electrons is dominant over the photon dose in the first few millimeter but is not taken into account by current standard treatment planning systems. The total energy spectrum of photons emerging from the source depends on the encapsulation composition and results in mean photon energies well above 100 keV. This is higher than the main gamma-ray energy peak at 84 keV. Based on our

  12. Discussion of discrete D shape toroidal coil

    International Nuclear Information System (INIS)

    Kaiho, Katsuyuki; Ohara, Takeshi; Agatsuma, Ko; Onishi, Toshitada

    1988-01-01

    A novel design for a toroidal coil, called the D shape coil, was reported by J. File. The coil conductors are in pure tension and then subject to no bending moment. This leads to a smaller number of emf supports in a simpler configuration than that with the conventional toroidal coil of circular cross-section. The contours of the D shape are given as solutions of a differential equation. This equation includes the function of the magnetic field distribution in the conductor region which is inversely proportional to the winding radius. It is therefore important to use the exact magnetic field distribution. However the magnetic field distribution becomes complicated when the D shape toroidal coil is comprised of discrete coils and also depends on the D shape configuration. A theory and a computer program for designing the practical pure-tension toroidal coil are developed. Using this computer code, D shape conductors are calculated for various numbers of discrete coils and the results are compared. Electromagnetic forces in the coils are also calculated. It is shown that the hoop stress in the conductors depends only on the total ampere-turns of the coil when the contours of the D shape are similar. (author)

  13. MO-A-BRC-00: TG167: Clinical Recommendations for Innovative Brachytherapy Devices and Applicators

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2016-06-15

    Although a multicenter, Phase III, prospective, randomized trial is the gold standard for evidence-based medicine, it is rarely used to evaluate innovative radiotherapy devices because of many practical and ethical reasons. It is usually sufficient to compare the dose distributions and dose rates for determining equivalence of the innovative device to an existing one. Thus, quantitative evaluation of the dosimetric characteristics of an innovative brachytherapy device or application is a critical part in which physicists are actively involved. The physicist’s role, along with physician colleagues, in this process is highlighted for innovative products or applications and includes evaluation of 1) dosimetric considerations for clinical implementation (including calibrations, dose calculations, and radiobiological aspects) to comply with existing societal dosimetric prerequisites for sources in routine clinical use, 2) risks and benefits from regulatory and safety perspectives, and 3) resource assessment and preparedness. Further, calibration methods should be traceable to a primary standards dosimetry laboratory such as NIST in the U.S. or to other primary standards dosimetry laboratory located elsewhere. Clinical users should follow standards as approved by their country’s regulatory agencies that approved such a brachytherapy device. Integration of this system into the medical source calibration infrastructure of secondary standard dosimetry laboratories such as the ADCLs is encouraged before a source is introduced into widespread routine clinical use. The AAPM and GEC-ESTRO have developed guidelines for the safe and consistent application of brachytherapy using innovative brachytherapy devices and applications. The current report covers regulatory approvals, calibration, dose calculations, radiobiological issues, and overall safety concerns that should be addressed during the commissioning stage preceding clinical use. These guidelines are based on review of

  14. MO-A-BRC-00: TG167: Clinical Recommendations for Innovative Brachytherapy Devices and Applicators

    International Nuclear Information System (INIS)

    2016-01-01

    Although a multicenter, Phase III, prospective, randomized trial is the gold standard for evidence-based medicine, it is rarely used to evaluate innovative radiotherapy devices because of many practical and ethical reasons. It is usually sufficient to compare the dose distributions and dose rates for determining equivalence of the innovative device to an existing one. Thus, quantitative evaluation of the dosimetric characteristics of an innovative brachytherapy device or application is a critical part in which physicists are actively involved. The physicist’s role, along with physician colleagues, in this process is highlighted for innovative products or applications and includes evaluation of 1) dosimetric considerations for clinical implementation (including calibrations, dose calculations, and radiobiological aspects) to comply with existing societal dosimetric prerequisites for sources in routine clinical use, 2) risks and benefits from regulatory and safety perspectives, and 3) resource assessment and preparedness. Further, calibration methods should be traceable to a primary standards dosimetry laboratory such as NIST in the U.S. or to other primary standards dosimetry laboratory located elsewhere. Clinical users should follow standards as approved by their country’s regulatory agencies that approved such a brachytherapy device. Integration of this system into the medical source calibration infrastructure of secondary standard dosimetry laboratories such as the ADCLs is encouraged before a source is introduced into widespread routine clinical use. The AAPM and GEC-ESTRO have developed guidelines for the safe and consistent application of brachytherapy using innovative brachytherapy devices and applications. The current report covers regulatory approvals, calibration, dose calculations, radiobiological issues, and overall safety concerns that should be addressed during the commissioning stage preceding clinical use. These guidelines are based on review of

  15. Dosimetric study in iodine-125 seeds for brachytherapy application

    International Nuclear Information System (INIS)

    Zeituni, Carlos Alberto

    2008-01-01

    The demand for iodine-125 seeds for use in brachytherapy treatments has experienced an increase along recent years in Brazil and all over the world. All iodine-125 seed must have its operational parameters measured and/or calculated every time changes in the production process are carried out. A complete dosimetric measurement is very expensive, and it is recommended that this procedure must be repeated at least once a year. Thus, this work developed a methodology for the entire dosimetric process. This methodology is based on the scarce information available in the literature, once almost all the methodology used in large industrial laboratories is commercial secret. The proposed methodology was tested using seeds of Amersham-Oncura-Ge Healthcare, which is the largest seed manufactory in the world. In this new methodology, an automatic reader was employed in order to reduce the time required in the selection process of the TLD-100 dosimeters used and a postprocessing of the obtained spectra was carried out. A total of 142 dosimeters were used and only 29 have been selected using the new methodology. Measurements were performed using slabs of Solid Water RW1 to simulate measuring in the 'water', using three different experimental apparatus and each measurement was repeated at least three times. The TLD-100 calibration was performed using a Dermopan II - Siemens. The measured values showed a good agreement with the ones available in the literature. Finally, these measured values were compared with calculated ones obtained by a semiempirical simulation program, showing a good agreement and, therefore, demonstrating the validity of the proposed methodology regarding dosimetric calculations. (author)

  16. [A new applicator with regulatable air bag designed for intracavitary brachytherapy of nasopharyngeal carcinoma].

    Science.gov (United States)

    Zhang, Ning; Wei, Guang-Yu; Tan, Yi-Chang; Huang, Ze-Li; Li, Shao-En; Lu, Zhi-Qian

    2004-10-01

    Nasopharynx applicator used in intracavitary brachytherapy plays an important role in the radiotherapy of nasopharyngeal carcinoma (NPC), its quality affects the efficiency of treatment. This study was to design a new applicator for clinical use. An inexpensive, reusable, and flexible latex nasopharynx applicator was designed. An air bag was placed at 15 mm from the foreside of the applicator, clung to the tube. The edge of air bag is tangent to the axis of tube. When the bag was full of air, the tube would hunch reversely,close to nasopharyngeal vault. After introduced into nasopharynx through middle nasal meatus, the applicator could be fixed in suitable position by its rotation, and air bag regulation, and confirmed its position by simulation. A total of 221 patients with NPC were treated with external beam radiation therapy in our hospital, and boosted HDR brachytherapy using this new applicator. The response rate was 92.6% in the primary tumor group (200/216), and 100% in the recurrent tumor group (5/5). Mucosal necrosis in the posterior or anterior wall of nasopharynx occurred in 5 patients, 8 patients experienced nasal congestion and nasal synechia. This new nasopharynx applicator is easy to operate, painless, and well dosage-distributed. Mucosal necrosis is likely due to higher fractional dose.

  17. 3D shape measurement system developed on mobile platform

    Science.gov (United States)

    Wu, Zhoujie; Chang, Meng; Shi, Bowen; Zhang, Qican

    2017-02-01

    Three-dimensional (3-D) shape measurement technology based on structured light has become one hot research field inspired by the increasing requirements. Many methods have been implemented and applied in the industry applications, but most of their equipments are large and complex, cannot be portable. Meanwhile, the popularity of the smart mobile terminals, such as smart phones, provides a platform for the miniaturization and portability of this technology. The measurement system based on phase-shift algorithm and Gray-code pattern under the Android platform on a mobile phone is mainly studied and developed, and it has been encapsulated into a mobile phone application in order to reconstruct 3-D shape data in the employed smart phone easily and quickly. The experimental results of two measured object are given in this paper and demonstrate the application we developed in the mobile platform is effective.

  18. Oxygenation status of cervical carcinomas before and during spinal anesthesia for application of brachytherapy

    International Nuclear Information System (INIS)

    Weitmann, H.D.; Knocke, T.H.; Poetter, R.; Gustorff, B.; Vaupel, P.

    2003-01-01

    Background and Purpose: To date, no information is available concerning the impact of spinal anesthesia on the oxygenation status of carcinomas of the uterine cervix. The aim of this study was therefore to determine the influence of spinal anesthesia on the oxygenation status of cervical carcinomas. Patients and Methods: In ten patients with cervical carcinoma who received spinal anesthesia for a first application of brachytherapy, intratumoral pO 2 measurements (pO 2 histography system, Eppendorf-Netheler-Hinz, Hamburg, Germany) were performed. Systemic parameters were documented prior to and during spinal anesthesia. Patients breathed room air spontaneously. For further evaluation, all intratumoral pO 2 values were pooled, and overall median pO 2 values and fractions of hypoxic pO 2 values ≤ 5 mm Hg were calculated. Overall median pO 2 values in the subcutis were also calculated. Results: There were no significant changes of systemic parameters, median subcutaneous pO 2 values, median intratumoral pO 2 values, and the fractions of hypoxic pO 2 values ≤ 5 mm Hg in the tumor upon administration of spinal anesthesia. The variability of measured pO 2 values increased during spinal anesthesia, although substantial changes in the oxygenation status were only seen in individual cases (n = 2). Conclusion: This study shows for the first time that the oxygenation status of cervical carcinomas, in general, is not influenced by spinal anesthesia prior to application of brachytherapy. To conclude, the data presented suggest that reliable pO 2 measurements can be performed under spinal anesthesia. At the same time, since no substantial changes in tumor oxygenation were observed, spinal anesthesia should not affect the O 2 -related efficacy of high-dose-rate brachytherapy. (orig.)

  19. Novel simple templates for reproducible positioning of skin applicators in brachytherapy

    Directory of Open Access Journals (Sweden)

    Silvia Rodríguez Villalba

    2016-08-01

    Full Text Available Purpose : Esteya and Valencia surface applicators are designed to treat skin tumors using brachytherapy. In clinical practice, in order to avoid errors that may affect the treatment outcome, there are two issues that need to be carefully addressed. First, the selected applicator for the treatment should provide adequate margin for the target, and second, the applicator has to be precisely positioned before each treatment fraction. In this work, we describe the development and use of a new acrylic templates named Template La Fe-ITIC. They have been designed specifically to help the clinical user in the selection of the correct applicator, and to assist the medical staff in reproducing the positioning of the applicator. These templates are freely available upon request. Material and methods: Templates that were developed by University and Polytechnic Hospital La Fe (La Fe and Hospital Clínica Benidorm (ITIC in cooperation with Elekta, consist of a thin sheet made of transparent acrylic. For each applicator, a crosshair and two different circles are drawn on these templates: the inner one corresponds to the useful beam, while the outer one represents the external perimeter of the applicator. The outer circle contains slits that facilitate to draw a circle on the skin of the patient for exact positioning of the applicator. In addition, there are two perpendicular rulers to define the adequate margin. For each applicator size, a specific template was developed. Results: The templates have been used successfully in our institutions for more than 50 patients’ brachytherapy treatments. They are currently being used for Esteya and Valencia applicators. Conclusions : The template La Fe-ITIC is simple and practical. It improves both the set-up time and reproducibility. It helps to establish the adequate margins, an essential point in the clinical outcome.

  20. Bio-absorption evaluation procedure with gamma irradiated for brachytherapy strand application

    International Nuclear Information System (INIS)

    Leme, Ednilse; Silva, Patricia C.P.; Rostelato, Maria Elisa C.M.; Moriguchi, Patricia; Ribeiro, Suzana P.; Manzoli, Jose E.

    2007-01-01

    Bio-absorbable sutures are largely used to hold and wind tissues together in good apposition until completing the healing process, without needing future removal. There are some materials commonly used for these sutures, such as polyglycolide, polylactide, poly(ecaprolactone), mucosa or beef intestines. Some of these materials have marked or moderate tissue reaction, like mucosa or beef intestines, and could not be used for some delicate applications, like braiding brachytherapy seed strands. The best option for this application is Vicryl sutures, trade mark of Johnson and Johnson company. Vicryl has a bio-absorption time still a little long, for brachytherapy application, but it could be accelerated imparting a dose of ionizing radiation in the strand, before using it. In this work, it is shown the procedure where small hanks of Vicryl wires (fifteen centimeters unrolled), surgical diameter number 7-0 (∼50 mm), were inserted into rats underskin and removed for mechanical and histological evaluation after 15, 30 and 60 days. Wire samples were irradiated with gamma doses of 10, 25 and 50 kGy, besides those non-irradiated. Preliminary mechanical evaluation was carried out in a EMIC DL 2000 machine, using NBR 13904 standard normative test. Fifty grays caused great degradation on wires, preventing any traction evaluation. Small doses are promising for accelerating bio-absorption and the samples mechanical tests results will be the scope of a future work. (author)

  1. Effect of pH grade on polymer-gel dosimeter and its brachytherapy application

    International Nuclear Information System (INIS)

    Spevacek, V.; Hrbacek, J.; Dvorak, P.; Cechak, T.; Novotny, J.

    2003-01-01

    To evaluate impact of pH grade on characteristics of polymer-gel dosimeter and its application in dose distribution verification in brachytherapy. A polymer-gel dosimeter based on radiation induced polymerization and crosslinking of acrylic monomers (acrylic acid, N,N' methylen-bis-acrylamide) was investigated with respect to its pH grade. pH grade of a dosimeter was varied by concentration of natrium hydroxide. Afterwards, dosimeter was split into several samples which were uniformly irradiated with Co-60 gamma rays. The range of doses applied was usually from 0 to 50 Gy with the main interest in region up to 20 Gy. Evaluation of dosimeter dose response was performed using MRI (T2). Dose response curves obtained were evaluated with respect to pH grade as a parameter. In parallel, there was studied temperature resistance (melting temperature) of gels with various pH grade. pH grade modified polymer-gel dosimeter was then used to compare dose distribution calculated with brachytherapy treatment planning system for simple irradiation geometry with Ir-192 HDR source. Additionaly, Monte Carlo calculated data were also included in the brachytherapy study. There was observed effect of pH grade on dose-response curve parameters (slope of linear fit, background response, linear range and maximum measurable dose). In general, the lower pH grade the higher sensitivity. Another positive effect of decreased pH grade is significantly higher maximum measurable dose. Maximum melting temperature of a gel was observed with pH grade between 3.5 and 4. For both higher and lower pH grades the melting temperature was lower. Using pH modified polymer-gel dosimeter simple brachytherapy dose distribution was measured and compared with calculated and Monte Carlo simulated data. There was observed strong dependence of dose-response relationship on pH grade of polymer-gel dosimeter resulting in significant improvement of dosimeter characteristics, namely sensitivity, applicable range of

  2. Radiation protection in brachytherapy

    International Nuclear Information System (INIS)

    Benitez, Manuel

    1996-02-01

    It covers technical procedures in medical applications for cancer treatment. Radiation protection principles in brachytherapy. Medical uses in therapy for Sr-90, Cs-137, Co-60, Ra-226, Ir-192, Au-198, Bi-214, Pb-214. (The author)

  3. Automated high-dose rate brachytherapy treatment planning for a single-channel vaginal cylinder applicator

    Science.gov (United States)

    Zhou, Yuhong; Klages, Peter; Tan, Jun; Chi, Yujie; Stojadinovic, Strahinja; Yang, Ming; Hrycushko, Brian; Medin, Paul; Pompos, Arnold; Jiang, Steve; Albuquerque, Kevin; Jia, Xun

    2017-06-01

    High dose rate (HDR) brachytherapy treatment planning is conventionally performed manually and/or with aids of preplanned templates. In general, the standard of care would be elevated by conducting an automated process to improve treatment planning efficiency, eliminate human error, and reduce plan quality variations. Thus, our group is developing AutoBrachy, an automated HDR brachytherapy planning suite of modules used to augment a clinical treatment planning system. This paper describes our proof-of-concept module for vaginal cylinder HDR planning that has been fully developed. After a patient CT scan is acquired, the cylinder applicator is automatically segmented using image-processing techniques. The target CTV is generated based on physician-specified treatment depth and length. Locations of the dose calculation point, apex point and vaginal surface point, as well as the central applicator channel coordinates, and the corresponding dwell positions are determined according to their geometric relationship with the applicator and written to a structure file. Dwell times are computed through iterative quadratic optimization techniques. The planning information is then transferred to the treatment planning system through a DICOM-RT interface. The entire process was tested for nine patients. The AutoBrachy cylindrical applicator module was able to generate treatment plans for these cases with clinical grade quality. Computation times varied between 1 and 3 min on an Intel Xeon CPU E3-1226 v3 processor. All geometric components in the automated treatment plans were generated accurately. The applicator channel tip positions agreed with the manually identified positions with submillimeter deviations and the channel orientations between the plans agreed within less than 1 degree. The automatically generated plans obtained clinically acceptable quality.

  4. SU-F-T-25: Design and Implementation of a Multi-Purpose Applicator for Pelvic Brachytherapy Applications

    Energy Technology Data Exchange (ETDEWEB)

    Bogue, J; Parsai, E [University of Toledo Medical Center, Toledo, OH (United States)

    2016-06-15

    Purpose: The current generation of inflatable multichannel brachytherapy applicators, such as the Varian Capri, have limited implementation to only vaginal and rectal cancers. While there are similar designs utilizing rigid, non-inflatable applicators, these alternatives could cause increased dose to surrounding tissue due to air gaps. Modification of the Capri could allow for easier treatment planning by reducing the number of channels and increased versatility by modifying the applicator to include an attachable single tandem for cervical or multiple tandems for endometrial applications. Methods: A Varian Capri applicator was simulated in water to replicate a patient. Multiple plans were optimized to deliver a prescribed dose of 100 cGy at 5mm away from the exterior of the applicator using six to thirteen existing channels. The current model was expanded upon to include a detachable tandem or multiple tandoms to increase its functionality to both cervical and endometrial cancers. Models were constructed in both threedimensional rendering software and Monte Carlo to allow prototyping and simulations. Results: Treatment plans utilizing six to thirteen channels produced limited dosimetric differences between channel arrangements, with a seven channel plan very closely approximating the thirteen channels. It was concluded that only seven channels would be necessary in future simulations to give an accurate representation of the applicator. Tandem attachments were prototyped for the applicator to demonstrate the ease of which they could be included. Future simulation in treatment planning software and Monte Carlo results will be presented to further define the ideal applicator geometry Conclusion: The current Capri applicator design could be easily modified to increase applicability to include cervical and endometrial treatments in addition to vaginal and rectal cancers. This new design helps in a more versatile single use applicator that can easily be inserted and to

  5. Studies on the preparation of 103Pd inner core of seed sources for brachytherapy applications

    International Nuclear Information System (INIS)

    Saha, Sujata; Manolkar, R.B.; Vimalnath, K.V.; Dash, A.; Venkatesh, Meera

    2007-01-01

    103 Pd seed sources are used widely world over for brachytherapy applications. 103 Pd available in-house was used to study its deposition on silver wire using electro-deposition and electroless deposition techniques with an aim to developing the inner core preparation of sealed radiation sources for treatment of prostate and ocular melanoma. Various parameters such as radioactive concentration of the feed solution, current density, time, temperature and pH of the solution were optimized to achieve maximum 103 Pd deposition on Ag wire. In electroless technique, the deposited amount of Pd was found to be nearly triple compared to electro-deposition in two hours time period. Both the methods gave nonleachable and well adherent sources. (author)

  6. Pelvic MRI application to the dosimetric analysis in Brachytherapy of Uterine Cervix Carcinoma

    International Nuclear Information System (INIS)

    Ahn, S. J.; Chung, W. K.; Nah, B. K.

    1997-01-01

    Before we report the results of curative radiotherapy in cervix cancer patients, we review the significance and safety of our dose specification methods in the brachytherapy system to have the insight of the potential predictive value of doses at specific points. We analyze the 45 cases of cervix cancer patients treated with intracavitary brachytherapy. In the lateral simulation film we draw the isodose curve and observe the absorbed dose rate of point A, the reference point of bladder(SBD) and rectum(SRD). In the sagittal view of pelvic MRI film we demarcate the tumor volume(TV) and determine whether the prescription dose curve of point A covers the tumor volume adequately by drawing the isodose curve as correctly as possible. Also we estimate the maximum point dose of bladder (MBD) and rectum (MRD) and calculate the inclusion area where the absorbed dose rate is higher than that of point A in the bladder (HBV) and rectum (HRV), respectively. Of forty-five cases, the isodose curve of point A seems to cover tumor volume optimally in only 24 (53%). The optimal tumor coverage seems to be associated not with the stage of the disease but with the tumor volume. There is no statistically significant association between SBD/SRD and MBD/MRD, respectively. SRD has statistically significant association with HBV and HRV. Our current treatment calculation methods seem to have the defect in the aspects of the nonoptimal coverage of the bulky tumor and the inappropriate estimation of bladder dose. We therefore need to modify the applicator geometry to optimize the dose distribution at the position of lower tandem source. Also it appears that the position of the bladder in relation to the applicators needs to be defined individually to define 'hot spots'. (author)

  7. TU-AB-201-07: Image Guided Endorectal HDR Brachytherapy Using a Compliant Balloon Applicator

    Energy Technology Data Exchange (ETDEWEB)

    Cohen, G; Goodman, K [Memorial Sloan Kettering Cancer Center, New York, NY (United States)

    2015-06-15

    Purpose: High dose rate endorectal brachytherapy is an option to deliver a focal, high-dose radiotherapy to rectal tumors for patients undergoing non-operative management. We investigate a new multichannel, MR compatible applicator with a novel balloon-based design to provide improved treatment geometry. We report on the initial clinical experience using this applicator. Methods: Patients were enrolled on an IRB-approved, dose-escalation protocol evaluating the use of the anorectal (AR-1) applicator (Ancer Medical, Hialeah, FL), a multichannel applicator with two concentric balloons. The inner balloon supports 8 source lumens; the compliant outer balloon expands to separate the normal rectal wall and the source lumens, yet deforms around a firm, exophytic rectal mass, leading to dose escalation to tumor while sparing normal rectum. Under general anesthesia, gold fiducial markers were inserted above and below the tumor, and the AR applicator was placed in the rectum. MRI-based treatment plans were prepared to deliver 15 Gy in 3 weekly fractions to the target volume while sparing healthy rectal tissue, bladder, bowel and anal muscles. Prior to each treatment, CBCT/Fluoroscopy were used to place the applicator in the treatment position and confirm the treatment geometry using rigid registration of the CBCT and planning MRI. After registration of the applicator images, positioning was evaluated based on the match of the gold markers. Results: Highly conformal treatment plans were achieved. MR compatibility of the applicator enabled good tumor visualization. In spite of the non-rigid nature of the applicators and the fact that a new applicator was used at each treatment session, treatment geometry was reproducible to within 2.5 mm. Conclusions: This is the first report on using the AR applicator in patients. Highly conformal plans, confidence in MRI target delineation, in combination with reproducible treatment geometry provide encouraging feedback for continuation with

  8. SU-F-T-08: Brachytherapy Film Dosimetry in a Water Phantom for a Ring and Tandem HDR Applicator

    International Nuclear Information System (INIS)

    Lee, B; Grelewicz, Z; Kang, Z; Cutright, D; Gopalakrishnan, M; Sathiaseelan, V; Zhang, H

    2016-01-01

    Purpose: The feasibility of dose measurement using new generation EBT3 film was explored in a water phantom for a ring and tandem HDR applicator for measurements tracking mucosal dose during cervical brachytherapy. Methods: An experimental fixture was assembled to position the applicator in a water phantom. Prior to measurement, calibration curves for EBT3 film in water and in solidwater were verified. EBT3 film was placed at different known locations around the applicator in the water tank. A CT scan of the phantom with applicator was performed using clinical protocol. A typical cervical cancer treatment plan was then generated by Oncentra brachytherapy planning system. A dose of 500 cGy was prescribed to point A (2 cm, 2 cm). Locations measured by film included the outer surface of the ring, measurement point A-m (2.2 cm, 2.2 cm), and profiles extending from point A-m parallel to the tandem. Three independent measurements were conducted. The doses recorded by film were carefully analyzed and compared with values calculated by the treatment planning system. Results: Assessment of the EBT3 films indicate that the dose at point A matches the values predicted by the planning system. Dose to the point A-m was 411.5 cGy, and the outer circumferential surface dose of the ring was between 500 and 1150 cGy. It was found that from the point A-m, the dose drops 60% within 4.5 cm on the line parallel to the tandem. The measurement doses agree with the treatment planning system. Conclusion: Use of EBT3 film is feasible for in-water measurements for brachytherapy. A carefully machined apparatus will likely improve measurement accuracy. In a typical plan, our study found that the ring surface dose can be 2.5 times larger than the point A prescription dose. EBT3 film can be used to monitor mucosal dose in brachytherapy treatments.

  9. SU-F-T-08: Brachytherapy Film Dosimetry in a Water Phantom for a Ring and Tandem HDR Applicator

    Energy Technology Data Exchange (ETDEWEB)

    Lee, B; Grelewicz, Z; Kang, Z; Cutright, D; Gopalakrishnan, M; Sathiaseelan, V; Zhang, H [Northwestern Memorial Hospital, Chicago, IL (United States)

    2016-06-15

    Purpose: The feasibility of dose measurement using new generation EBT3 film was explored in a water phantom for a ring and tandem HDR applicator for measurements tracking mucosal dose during cervical brachytherapy. Methods: An experimental fixture was assembled to position the applicator in a water phantom. Prior to measurement, calibration curves for EBT3 film in water and in solidwater were verified. EBT3 film was placed at different known locations around the applicator in the water tank. A CT scan of the phantom with applicator was performed using clinical protocol. A typical cervical cancer treatment plan was then generated by Oncentra brachytherapy planning system. A dose of 500 cGy was prescribed to point A (2 cm, 2 cm). Locations measured by film included the outer surface of the ring, measurement point A-m (2.2 cm, 2.2 cm), and profiles extending from point A-m parallel to the tandem. Three independent measurements were conducted. The doses recorded by film were carefully analyzed and compared with values calculated by the treatment planning system. Results: Assessment of the EBT3 films indicate that the dose at point A matches the values predicted by the planning system. Dose to the point A-m was 411.5 cGy, and the outer circumferential surface dose of the ring was between 500 and 1150 cGy. It was found that from the point A-m, the dose drops 60% within 4.5 cm on the line parallel to the tandem. The measurement doses agree with the treatment planning system. Conclusion: Use of EBT3 film is feasible for in-water measurements for brachytherapy. A carefully machined apparatus will likely improve measurement accuracy. In a typical plan, our study found that the ring surface dose can be 2.5 times larger than the point A prescription dose. EBT3 film can be used to monitor mucosal dose in brachytherapy treatments.

  10. MO-AB-BRA-02: Modeling Nanoparticle-Eluting Spacer Degradation During Brachytherapy Application with in Situ Dose-Painting

    Energy Technology Data Exchange (ETDEWEB)

    Boateng, F [University of Massachusetts Lowell, Lowell, Massachusetts (United States); Ngwa, W [University of Massachusetts Lowell, Lowell, Massachusetts (United States); Harvard Medical School, Boston, MA (United States)

    2016-06-15

    Purpose: Brachytherapy application with in situ dose-painting using gold nanoparticles (GNP) released from GNP-loaded brachytherapy spacers has been proposed as an innovative approach to increase therapeutic efficacy during brachytherapy. This work investigates the dosimetric impact of slow versus burst release of GNP from next generation biodegradable spacers. Methods: Mathematical models were developed based on experimental data to study the release of GNP from a spacer designed with FDA approved poly(lactic-co-glycolic acid) (PLGA) polymer. The diffusion controlled released process and PLGA polymer degradation kinetics was incorporated in the calculations for the first time. An in vivo determined diffusion coefficient was used for determining the concentration profiles and corresponding dose enhancement based on initial GNP-loading concentrations of 7 mg/g. Results: The results showed that there is significant delay before the concentration profile of GNP diffusion in the tumor is similar to that when burst release is assumed as in previous studies. For example, in the case of burst release after spacer administration, it took up to 25 days for all the GNP to be released from the spacer using diffusion controlled release process only. However, it took up to 45 days when a combined model for both diffusion and polymer degradation processes was used. Based on the tumor concentration profiles, a significant dose enhancement factor (DEF >20%), could be attained at a tumor distances of 5 mm from a spacer loaded with 10 nm GNP sizes. Conclusion: The results highlight the need to take the slow release of GNP from spacers and factors such as biodegradation of polymers into account in research development of GNP-eluting spacers for brachytherapy applications with in-situ dose-painting using gold nanoparticles. The findings suggest that I-125 may be the more appropriate for such applications given the relatively longer half-live compared to other radioisotopes like Pd-103

  11. SU-E-T-362: Automatic Catheter Reconstruction of Flap Applicators in HDR Surface Brachytherapy

    International Nuclear Information System (INIS)

    Buzurovic, I; Devlin, P; Hansen, J; O'Farrell, D; Bhagwat, M; Friesen, S; Damato, A; Lewis, J; Cormack, R

    2014-01-01

    Purpose: Catheter reconstruction is crucial for the accurate delivery of radiation dose in HDR brachytherapy. The process becomes complicated and time-consuming for large superficial clinical targets with a complex topology. A novel method for the automatic catheter reconstruction of flap applicators is proposed in this study. Methods: We have developed a program package capable of image manipulation, using C++class libraries of The-Visualization-Toolkit(VTK) software system. The workflow for automatic catheter reconstruction is: a)an anchor point is placed in 3D or in the axial view of the first slice at the tip of the first, last and middle points for the curved surface; b)similar points are placed on the last slice of the image set; c)the surface detection algorithm automatically registers the points to the images and applies the surface reconstruction filter; d)then a structured grid surface is generated through the center of the treatment catheters placed at a distance of 5mm from the patient's skin. As a result, a mesh-style plane is generated with the reconstructed catheters placed 10mm apart. To demonstrate automatic catheter reconstruction, we used CT images of patients diagnosed with cutaneous T-cell-lymphoma and imaged with Freiburg-Flap-Applicators (Nucletron™-Elekta, Netherlands). The coordinates for each catheter were generated and compared to the control points selected during the manual reconstruction for 16catheters and 368control point Results: The variation of the catheter tip positions between the automatically and manually reconstructed catheters was 0.17mm(SD=0.23mm). The position difference between the manually selected catheter control points and the corresponding points obtained automatically was 0.17mm in the x-direction (SD=0.23mm), 0.13mm in the y-direction (SD=0.22mm), and 0.14mm in the z-direction (SD=0.24mm). Conclusion: This study shows the feasibility of the automatic catheter reconstruction of flap applicators with a high

  12. Surface applicators for high dose rate brachytherapy in AIDS-related kaposi's sarcoma

    International Nuclear Information System (INIS)

    Evans, Michael D.C.; Yassa, Mariam; Podgorsak, Ervin B.; Roman, Ted N.; Schreiner, L. John; Souhami, Luis

    1997-01-01

    Purpose: The development of commercially available surface applicators using high dose rate remote afterloading devices has enabled radiotherapy centers to treat selected superficial lesions using a remote afterloading brachytherapy unit. The dosimetric parameters of these applicators, the clinical implementation of this technique, and a review of the initial patient treatment regimes are presented. Methods and Materials: A set of six fixed-diameter (1, 2, and 3 cm), tungsten/steel surface applicators is available for use with a single stepping-source (Ir-192, 370 GBq) high dose rate afterloader. The source can be positioned either in a parallel or perpendicular orientation to the treatment plane at the center of a conical aperture that sits at an SSD of approximately 15 mm and is used with a 1-mm thick removable plastic cap. The surface dose rates, percent depth dose, and off-axis ratios were measured. A custom-built, ceiling-mounted immobilization device secures the applicator on the surface of the patient's lesion during treatment. Results: Between November 1994, and September 1996, 16 AIDS-related Kaposi's sarcoma patients having a total of 120 lesions have been treated with palliative intent. Treatment sites were distributed between the head and neck, extremity, and torso. Doses ranged from 8 to 20 Gy, with a median dose of 10 Gy delivered in a single fraction. Treatments were well tolerated with minimal skin reaction, except for patients with lesions treated to 20 Gy who developed moderate/severe desquamation. Conclusion: Radiotherapy centers equipped with a high dose rate remote afterloading unit may treat small selected surface lesions with commercially available surface applicators. These surface applicators must be used with a protective cap to eliminate electron contamination. The optimal surface dose appears to be either 10 or 15 Gy depending upon the height of the lesion

  13. Dosimetric effects of saline- versus water-filled balloon applicators for IORT using the model S700 electronic brachytherapy source.

    Science.gov (United States)

    Redler, Gage; Templeton, Alistair; Zhen, Heming; Turian, Julius; Bernard, Damian; Chu, James C H; Griem, Katherine L; Liao, Yixiang

    The Xoft Axxent Electronic Brachytherapy System (Xoft, Inc., San Jose, CA) is a viable option for intraoperative radiation therapy (IORT) treatment of early-stage breast cancer. The low-energy (50-kVp) X-ray source simplifies shielding and increases relative biological effectiveness but increases dose distribution sensitivity to medium composition. Treatment planning systems typically assume homogenous water for brachytherapy dose calculations, including precalculated atlas plans for Xoft IORT. However, Xoft recommends saline for balloon applicator filling. This study investigates dosimetric differences due to increased effective atomic number (Z eff ) for saline (Z eff  = 7.56) versus water (Z eff  = 7.42). Balloon applicator diameters range from 3 to 6 cm. Monte Carlo N-Particle software is used to calculate dose at the surface (D s ) of and 1 cm away (D 1cm ) from the water-/saline-filled balloon applicator using a single dwell at the applicator center as a simple estimation of the dosimetry and multiple dwells simulating the clinical dose distributions for the atlas plans. Single-dwell plans show a 4.4-6.1% decrease in D s for the 3- to 6-cm diameter applicators due to the saline. Multidwell plans show similar results: 4.9% and 6.4% D s decrease, for 4-cm and 6-cm diameter applicators, respectively. For the single-dwell plans, D 1cm decreases 3.6-5.2% for the 3- to 6-cm diameter applicators. For the multidwell plans, D 1cm decreases 3.3% and 5.3% for the 4-cm and 6-cm applicators, respectively. The dosimetric effect introduced by saline versus water filling for Xoft balloon applicator-based IORT treatments is ∼5%. Users should be aware of this in the context of both treatment planning and patient outcome studies. Copyright © 2017 American Brachytherapy Society. Published by Elsevier Inc. All rights reserved.

  14. Implantation of xenon in amorphous carbon and silicon for brachytherapy application

    International Nuclear Information System (INIS)

    Marques, F.C.; Barbieri, P.F.; Viana, G.A.; Silva, D.S. da

    2013-01-01

    We report a procedure to implant high dose of xenon atoms (Xe) in amorphous carbon, a-C, and amorphous silicon, a-Si, for application in brachytherapy seeds. An ion beam assisted deposition (IBAD) system was used for the deposition of the films, where one ion gun was used for sputtering a carbon (or silicon) target, while the other ion gun was used to simultaneously bombard the growing film with a beam of xenon ion Xe + in the 0–300 eV range. Xe atoms were implanted into the film with concentration up to 5.5 at.%, obtained with Xe bombardment energy in the 50–150 eV range. X-ray absorption spectroscopy was used to investigate the local arrangement of the implanted Xe atoms through the Xe L III absorption edge (4.75 keV). It was observed that Xe atoms tend to agglomerate in nanoclusters in a-C and are dispersed in a-Si.

  15. SU-E-T-661: Quantitative MRI Assessment of a Novel Direction-Modulated Brachytherapy Tandem Applicator for Cervical Cancer

    Energy Technology Data Exchange (ETDEWEB)

    Soliman, A; Elzibak, A; Fatemi, A; Safigholi, H; Leung, E; Ravi, A; Song, W [Sunnybrook Research Institute, Sunnybrook Health Sciences Centre, Toronto, Ontario (Canada); Han, D [Sunnybrook Research Institute, Sunnybrook Health Sciences Centre, Toronto, Ontario (Canada); University of California, San Diego, La Jolla, CA (United States)

    2015-06-15

    Purpose: To quantitatively evaluate the MR image quality of a novel direction modulated brachytherapy (DMBT) tandem applicator for cervical cancer, using the clinical MRI scanning protocol for image guided brachytherapy. Methods: The tungsten alloy-based applicator was placed in a water phantom and clinical imaging protocol was performed. Axial images were acquired using 2D turbo-spin echo (TSE) T2-weighted sequence on a 1.5T GE 450w MR scanner and an 8-channel body coil. As multi-channel receiver coil was used, inhomogeneities in the B1 receive field must be considered before performing the quantification process. Therefore the applicator was removed from the phantom and the whole imaging session was performed again for the water phantom with the same parameters. Images from the two scans were then subtracted, resulting in a difference image that only shows the applicator with its surrounding magnetic susceptibility dipole artifact. Line profiles were drawn and plotted on the difference image at various angles and locations along the tandem. Full width at half maximum (FWHM) was measured at all the line profiles to quantify the extent of the artifact. Additionally, the extent of the artifact along the diameter of the tandem was measured at various angles and locations. Results: After removing the background inhomogeneities of the receiver coil, FWHM of the tandem measured 5.75 ± 0.35 mm (the physical tandem diameter is 5.4 mm). The average extent of the artifacts along the diameter of the tandem measured is 2.14 ± 0.56 mm. In contrast to CT imaging of the same applicator (not shown here), the tandem can be easily identified without additional correction algorithms. Conclusion: This work demonstrated that the novel DMBT tandem applicator has minimal susceptibility artifact in T2-weighted images employed in clinical practice for MRI-guided brachytherapy of cervical cancer.

  16. SU-E-T-04: 3D Printed Patient-Specific Surface Mould Applicators for Brachytherapy Treatment of Superficial Lesions

    International Nuclear Information System (INIS)

    Cumming, I; Lasso, A; Rankin, A; Fichtinger, G; Joshi, C P; Falkson, C; Schreiner, L John

    2014-01-01

    Purpose: Evaluate the feasibility of constructing 3D-printed patient-specific surface mould applicators for HDR brachytherapy treatment of superficial lesions. Methods: We propose using computer-aided design software to create 3D printed surface mould applicators for brachytherapy. A mould generation module was developed in the open-source 3D Slicer ( http://www.slicer.org ) medical image analysis platform. The system extracts the skin surface from CT images, and generates smooth catheter paths over the region of interest based on user-defined start and end points at a specified stand-off distance from the skin surface. The catheter paths are radially extended to create catheter channels that are sufficiently wide to ensure smooth insertion of catheters for a safe source travel. An outer mould surface is generated to encompass the channels. The mould is also equipped with fiducial markers to ensure its reproducible placement. A surface mould applicator with eight parallel catheter channels of 4mm diameters was fabricated for the nose region of a head phantom; flexible plastic catheters of 2mm diameter were threaded through these channels maintaining 10mm catheter separations and a 5mm stand-off distance from the skin surface. The apparatus yielded 3mm thickness of mould material between channels and the skin. The mould design was exported as a stereolithography file to a Dimension SST1200es 3D printer and printed using ABS Plus plastic material. Results: The applicator closely matched its design and was found to be sufficiently rigid without deformation during repeated application on the head phantom. Catheters were easily threaded into channels carved along catheter paths. Further tests are required to evaluate feasibility of channel diameters smaller than 4mm. Conclusion: Construction of 3D-printed mould applicators show promise for use in patient specific brachytherapy of superficial lesions. Further evaluation of 3D printing techniques and materials is required

  17. SU-E-T-04: 3D Printed Patient-Specific Surface Mould Applicators for Brachytherapy Treatment of Superficial Lesions

    Energy Technology Data Exchange (ETDEWEB)

    Cumming, I; Lasso, A; Rankin, A; Fichtinger, G [Laboratory for Percutaneous Surgery, School of Computing, Queen' s University, Kingston, Ontario (Canada); Joshi, C P; Falkson, C; Schreiner, L John [CCSEO, Kingston General Hospital and Department of Oncology, Queen' s University, Kingston, Ontario (Canada)

    2014-06-01

    Purpose: Evaluate the feasibility of constructing 3D-printed patient-specific surface mould applicators for HDR brachytherapy treatment of superficial lesions. Methods: We propose using computer-aided design software to create 3D printed surface mould applicators for brachytherapy. A mould generation module was developed in the open-source 3D Slicer ( http://www.slicer.org ) medical image analysis platform. The system extracts the skin surface from CT images, and generates smooth catheter paths over the region of interest based on user-defined start and end points at a specified stand-off distance from the skin surface. The catheter paths are radially extended to create catheter channels that are sufficiently wide to ensure smooth insertion of catheters for a safe source travel. An outer mould surface is generated to encompass the channels. The mould is also equipped with fiducial markers to ensure its reproducible placement. A surface mould applicator with eight parallel catheter channels of 4mm diameters was fabricated for the nose region of a head phantom; flexible plastic catheters of 2mm diameter were threaded through these channels maintaining 10mm catheter separations and a 5mm stand-off distance from the skin surface. The apparatus yielded 3mm thickness of mould material between channels and the skin. The mould design was exported as a stereolithography file to a Dimension SST1200es 3D printer and printed using ABS Plus plastic material. Results: The applicator closely matched its design and was found to be sufficiently rigid without deformation during repeated application on the head phantom. Catheters were easily threaded into channels carved along catheter paths. Further tests are required to evaluate feasibility of channel diameters smaller than 4mm. Conclusion: Construction of 3D-printed mould applicators show promise for use in patient specific brachytherapy of superficial lesions. Further evaluation of 3D printing techniques and materials is required

  18. Surface applicator calibration and commissioning of an electronic brachytherapy system for nonmelanoma skin cancer treatment

    International Nuclear Information System (INIS)

    Rong, Yi; Welsh, James S.

    2010-01-01

    Purpose: The Xoft Axxent x-ray source has been used for treating nonmelanoma skin cancer since the surface applicators became clinically available in 2009. The authors report comprehensive calibration procedures for the electronic brachytherapy (eBx) system with the surface applicators. Methods: The Xoft miniature tube (model S700) generates 50 kVp low-energy x rays. The new surface applicators are available in four sizes of 10, 20, 35, and 50 mm in diameter. The authors' tests include measurements of dose rate, air-gap factor, output stability, depth dose verification, beam flatness and symmetry, and treatment planning with patient specific cutout factors. The TG-61 in-air method was used as a guideline for acquiring nominal dose-rate output at the skin surface. A soft x-ray parallel-plate chamber (PTW T34013) and electrometer was used for the output commissioning. GafChromic EBT films were used for testing the properties of the treatment fields with the skin applicators. Solid water slabs were used to verify the depth dose and cutout factors. Patients with basal cell or squamous cell carcinoma were treated with eBx using a calibrated Xoft system with the low-energy x-ray source and the skin applicators. Results: The average nominal dose-rate output at the skin surface for the 35 mm applicator is 1.35 Gy/min with ±5% variation for 16 sources. The dose-rate output and stability (within ±5% variation) were also measured for the remaining three applicators. For the same source, the output variation is within 2%. The effective source-surface distance was calculated based on the air-gap measurements for four applicator sizes. The field flatness and symmetry are well within 5%. Percentage depth dose in water was provided by factory measurements and can be verified using solid water slabs. Treatment duration was calculated based on the nominal dose rate, the prescription fraction size, the depth dose percentage, and the cutout factor. The output factor needs to be

  19. Surface applicator calibration and commissioning of an electronic brachytherapy system for nonmelanoma skin cancer treatment

    Energy Technology Data Exchange (ETDEWEB)

    Rong, Yi; Welsh, James S. [Department of Human Oncology, University of Wisconsin School of Medicine and Public Health, Madison, Wisconsin 53792 and University of Wisconsin Cancer Center-Riverview, Riverview Hospital Association, Wisconsin Rapids, Wisconsin 54494 (United States); Department of Human Oncology and Medical Physics, University of Wisconsin School of Medicine and Public Health, Madison, Wisconsin 53792 and University of Wisconsin Cancer Center-Riverview, Riverview Hospital Association, Wisconsin Rapids, Wisconsin 54494 (United States)

    2010-10-15

    Purpose: The Xoft Axxent x-ray source has been used for treating nonmelanoma skin cancer since the surface applicators became clinically available in 2009. The authors report comprehensive calibration procedures for the electronic brachytherapy (eBx) system with the surface applicators. Methods: The Xoft miniature tube (model S700) generates 50 kVp low-energy x rays. The new surface applicators are available in four sizes of 10, 20, 35, and 50 mm in diameter. The authors' tests include measurements of dose rate, air-gap factor, output stability, depth dose verification, beam flatness and symmetry, and treatment planning with patient specific cutout factors. The TG-61 in-air method was used as a guideline for acquiring nominal dose-rate output at the skin surface. A soft x-ray parallel-plate chamber (PTW T34013) and electrometer was used for the output commissioning. GafChromic EBT films were used for testing the properties of the treatment fields with the skin applicators. Solid water slabs were used to verify the depth dose and cutout factors. Patients with basal cell or squamous cell carcinoma were treated with eBx using a calibrated Xoft system with the low-energy x-ray source and the skin applicators. Results: The average nominal dose-rate output at the skin surface for the 35 mm applicator is 1.35 Gy/min with {+-}5% variation for 16 sources. The dose-rate output and stability (within {+-}5% variation) were also measured for the remaining three applicators. For the same source, the output variation is within 2%. The effective source-surface distance was calculated based on the air-gap measurements for four applicator sizes. The field flatness and symmetry are well within 5%. Percentage depth dose in water was provided by factory measurements and can be verified using solid water slabs. Treatment duration was calculated based on the nominal dose rate, the prescription fraction size, the depth dose percentage, and the cutout factor. The output factor needs

  20. Surface applicator calibration and commissioning of an electronic brachytherapy system for nonmelanoma skin cancer treatment.

    Science.gov (United States)

    Rong, Yi; Welsh, James S

    2010-10-01

    The Xoft Axxent x-ray source has been used for treating nonmelanoma skin cancer since the surface applicators became clinically available in 2009. The authors report comprehensive calibration procedures for the electronic brachytherapy (eBx) system with the surface applicators. The Xoft miniature tube (model S700) generates 50 kVp low-energy x rays. The new surface applicators are available in four sizes of 10, 20, 35, and 50 mm in diameter. The authors' tests include measurements of dose rate, air-gap factor, output stability, depth dose verification, beam flatness and symmetry, and treatment planning with patient specific cutout factors. The TG-61 in-air method was used as a guideline for acquiring nominal dose-rate output at the skin surface. A soft x-ray parallel-plate chamber (PTW T34013) and electrometer was used for the output commissioning. GafChromic EBT films were used for testing the properties of the treatment fields with the skin applicators. Solid water slabs were used to verify the depth dose and cutout factors. Patients with basal cell or squamous cell carcinoma were treated with eBx using a calibrated Xoft system with the low-energy x-ray source and the skin applicators. The average nominal dose-rate output at the skin surface for the 35 mm applicator is 1.35 Gy/min with +/- 5% variation for 16 sources. The dose-rate output and stability (within +/- 5% variation) were also measured for the remaining three applicators. For the same source, the output variation is within 2%. The effective source-surface distance was calculated based on the air-gap measurements for four applicator sizes. The field flatness and symmetry are well within 5%. Percentage depth dose in water was provided by factory measurements and can be verified using solid water slabs. Treatment duration was calculated based on the nominal dose rate, the prescription fraction size, the depth dose percentage, and the cutout factor. The output factor needs to be measured for each case with

  1. SU-E-T-10: A Clinical Implementation and the Dosimetric Evidence in High Dose Rate Vaginal Multichannel Applicator Brachytherapy

    Energy Technology Data Exchange (ETDEWEB)

    Syh, J; Syh, J; Patel, B; Zhang, J; Wu, H; Rosen, L [Willis-Knighton Medical Center, Shreveport, LA (United States)

    2015-06-15

    Purpose: The multichannel cylindrical applicator has a distinctive modification of the traditional single channel cylindrical applicator. The novel multichannel applicator has additional peripheral channels that provide more flexibility both in treatment planning process and outcomes. To protect by reducing doses to adjacent organ at risk (OAR) while maintaining target coverage with inverse plan optimization are the goals for such novel Brachytherapy device. Through a series of comparison and analysis of reults in more than forty patients who received HDR Brachytherapy using multichannel vaginal applicator, this procedure has been implemented in our institution. Methods: Multichannel planning was CT image based. The CTV of 5mm vaginal cuff rind with prescribed length was well reconstructed as well as bladder and rectum. At least D95 of CTV coverage is 95% of prescribed dose. Multichannel inverse plan optimization algorithm not only shapes target dose cloud but set dose avoids to OAR’s exclusively. The doses of D2cc, D5cc and D5; volume of V2Gy in OAR’s were selected to compare with single channel results when sole central channel is only possibility. Results: Study demonstrates plan superiorly in OAR’s doe reduction in multi-channel plan. The D2cc of the rectum and bladder were showing a little lower for multichannel vs. single channel. The V2Gy of the rectum was 93.72% vs. 83.79% (p=0.007) for single channel vs. multichannel respectively. Absolute reduced mean dose of D5 by multichannel was 17 cGy (s.d.=6.4) and 44 cGy (s.d.=15.2) in bladder and rectum respectively. Conclusion: The optimization solution in multichannel was to maintain D95 CTV coverage while reducing the dose to OAR’s. Dosimetric advantage in sparing critical organs by using a multichannel applicator in HDR Brachytherapy treatment of the vaginal cuff is so promising and has been implemented clinically.

  2. 3D shaping of electron beams using amplitude masks

    Energy Technology Data Exchange (ETDEWEB)

    Shiloh, Roy, E-mail: royshilo@post.tau.ac.il; Arie, Ady

    2017-06-15

    Highlights: • Electron beams are shaped in 3D with examples of curves and lattices. • Computer generated holograms are manifested as binary amplitude masks. • Applications in electron-optical particle trapping, manipulation, and synthesis. • Electron beam lithography fabrication scheme explained in detail. • Measurement paradigms of 3D shaped beams are discussed. - Abstract: Shaping the electron wavefunction in three dimensions may prove to be an indispensable tool for research involving atomic-sized particle trapping, manipulation, and synthesis. We utilize computer-generated holograms to sculpt electron wavefunctions in a standard transmission electron microscope in 3D, and demonstrate the formation of electron beams exhibiting high intensity along specific trajectories as well as shaping the beam into a 3D lattice of hot-spots. The concepts presented here are similar to those used in light optics for trapping and tweezing of particles, but at atomic scale resolutions.

  3. Reconstruction of MRI/CT compatible ring and tandem applicators in CT or MRI images used for treatment planning in brachytherapy

    International Nuclear Information System (INIS)

    Surendran, N.; Kim, Hayeon; Beriwal, Sushil; Saiful Huq, M.

    2008-01-01

    Brachytherapy (BT) plays a crucial role in the management of invasive cervix cancer from stage I to IV. Intracavitary techniques are based on afterloading devices, with different types of applicators. CT and/or MRI compatible applicators allow a sectional image based approach with a better assessment of gross tumour volume (GTV) and definition and delineation of target volume (CTV) compared to traditional approaches. To evaluate reconstruction of MRI/CT compatible ring and tandem applicators in 3D CT or MRI images used for treatment planning in Brachytherapy

  4. Dosimetric evaluation of a combination of brachytherapy applicators for uterine cervix cancer with involvement of the distal vagina

    International Nuclear Information System (INIS)

    Guimaraes, Roger Guilherme Rodrigues

    2009-01-01

    Objective: To evaluate an alternative brachytherapy technique for uterine cervix cancer involving the distal vagina, without increasing the risk of toxicity. Materials And Methods: Theoretical study comparing three different high-dose rate intracavitary brachytherapy applicators: intrauterine tandem and vaginal cylinder (TC); tandem/ring applicator combined with vaginal cylinder (TR+C); and a virtual applicator combining both the tandem/ring and vaginal cylinder in a single device (TRC). Prescribed doses were 7 Gy at point A, and 5 Gy on the surface or at a 5 mm depth of the vaginal mucosa. Doses delivered to the rectum, bladder and sigmoid colon were kept below the tolerance limits. Volumes covered by the isodoses, respectively, 50% (V50), 100% (V100), 150% (V150) and 200% (V200) were compared. Results: Both the combined TR+C and TRC presented a better dose distribution as compared with the TC applicator. The TR+C dose distribution was similar to the TRC dose, with V150 and V200 being about 50% higher for TR+C (within the cylinder). Conclusion: Combined TR+C in a two-time single application may represent an alternative therapy technique for patients affected by uterine cervix cancer involving the distal vagina. (author)

  5. SU-G-201-04: Can the Dynamic Library of Flap Applicators Replace Treatment Planning in Surface Brachytherapy?

    Energy Technology Data Exchange (ETDEWEB)

    Buzurovic, I; Devlin, P; Hansen, J; O’Farrell, D; Bhagwat, M; Friesen, S; Damato, A; Harris, T; Cormack, R [Dana-Farber/Brigham and Women’s Cancer Center, Harvard Medical School, Boston, MA (United States)

    2016-06-15

    Purpose: Contemporary brachytherapy treatment planning systems-(TPS) include the applicator model libraries to improve digitization; however, the library of surface-flap-applicators-(SFA) is not incorporated into the commercial TPS. We propose the dynamic library-(DL) for SFA and investigate if such library can eliminate applicator reconstruction, source activation and dose normalization. Methods: DL was generated for the SFA using the C++class libraries of the Visualization Toolkit-(VTK) and Qt-application framework for complete abstraction of the graphical interface. DL was designed such that the user can initially choose the size of the applicator that corresponds to the one clinically placed to the patient. The virtual applicator-(VA) has an elastic property so that it can be registered to the clinical CT images with a real applicator-(RA) on it. The VA and RA matching is performed by adjusting the position and curvature of the VA. The VA does not elongate or change its size so each catheter could always be at a distance of 5mm from the skin and 10mm apart from the closest catheter maintaining the physical accuracy of the clinical setup. Upon the applicator placement, the dwell positions were automatically activated, and the dose is normalized to the prescription depth. The accuracy of source positioning was evaluated using various applicator sizes. Results: The accuracy of the applicator placement was in the sub-millimeter range. The time-study reveals that up to 50% of the planning time can be saved depending on the complexity of the clinical setup. Unlike in the classic approach, the planning time was not highly dependent on the applicator size. Conclusion: The practical benefits of the DL of the SFA were demonstrated. The time demanding planning processes can be partially automated. Consequently, the planner can dedicate effort to fine tuning, which can result in the improvement of the quality of treatment plans in surface brachytherapy.

  6. SU-G-201-04: Can the Dynamic Library of Flap Applicators Replace Treatment Planning in Surface Brachytherapy?

    International Nuclear Information System (INIS)

    Buzurovic, I; Devlin, P; Hansen, J; O’Farrell, D; Bhagwat, M; Friesen, S; Damato, A; Harris, T; Cormack, R

    2016-01-01

    Purpose: Contemporary brachytherapy treatment planning systems-(TPS) include the applicator model libraries to improve digitization; however, the library of surface-flap-applicators-(SFA) is not incorporated into the commercial TPS. We propose the dynamic library-(DL) for SFA and investigate if such library can eliminate applicator reconstruction, source activation and dose normalization. Methods: DL was generated for the SFA using the C++class libraries of the Visualization Toolkit-(VTK) and Qt-application framework for complete abstraction of the graphical interface. DL was designed such that the user can initially choose the size of the applicator that corresponds to the one clinically placed to the patient. The virtual applicator-(VA) has an elastic property so that it can be registered to the clinical CT images with a real applicator-(RA) on it. The VA and RA matching is performed by adjusting the position and curvature of the VA. The VA does not elongate or change its size so each catheter could always be at a distance of 5mm from the skin and 10mm apart from the closest catheter maintaining the physical accuracy of the clinical setup. Upon the applicator placement, the dwell positions were automatically activated, and the dose is normalized to the prescription depth. The accuracy of source positioning was evaluated using various applicator sizes. Results: The accuracy of the applicator placement was in the sub-millimeter range. The time-study reveals that up to 50% of the planning time can be saved depending on the complexity of the clinical setup. Unlike in the classic approach, the planning time was not highly dependent on the applicator size. Conclusion: The practical benefits of the DL of the SFA were demonstrated. The time demanding planning processes can be partially automated. Consequently, the planner can dedicate effort to fine tuning, which can result in the improvement of the quality of treatment plans in surface brachytherapy.

  7. Dosimetric evaluation of a novel high dose rate (HDR) intraluminal / interstitial brachytherapy applicator for gastrointestinal and bladder cancers

    Science.gov (United States)

    Aghamiri, Seyyed Mahmoud Reza; Najarian, Siamak; Jaberi, Ramin

    2010-01-01

    High dose rate (HDR) brachytherapy is one of the accepted treatment modalities in gastro‐intestinal tract and bladder carcinomas. Considering the shortcoming of contact brachytherapy routinely used in gastrointestinal tract in treatment of big tumors or invasive method of bladder treatment, an intraluminal applicator with the capability of insertion into the tumor depth seems to be useful. This study presents some dosimetric evaluations to introduce this applicator to the clinical use. The radiation attenuation characteristics of the applicator were evaluated by means of two dosimetric methods including well‐type chamber and radiochromic film. The proposed 110 cm long applicator has a flexible structure made of stainless steel for easy passage through lumens and a needle tip to drill into big tumors. The 2 mm diameter of the applicator is thick enough for source transition, while easy passage through any narrow lumen such as endoscope or cystoscope working channel is ensured. Well‐chamber results showed an acceptably low attenuation of this steel springy applicator. Performing absolute dosimetry resulted in a correlation coefficient of R=0.9916(p‐value≈10−7) between standard interstitial applicator and the one proposed in this article. This study not only introduces a novel applicator with acceptable attenuation but also proves the response independency of the GAFCHROMIC EBT films to energy. By applying the dose response of the applicator in the treatment planning software, it can be used as a new intraluminal / interstitial applicator. PACS number: 87.53.Bn, 87.53.Jw, 29.40.Cs

  8. Multicentre treatment planning study of MRI-guided brachytherapy for cervical cancer: Comparison between tandem-ovoid applicator users

    International Nuclear Information System (INIS)

    Nomden, Christel N.; Leeuw, Astrid A.C. de; Van Limbergen, Erik; Brabandere, Marisol de; Nulens, An; Nout, Remi A.; Laman, Mirjam; Ketelaars, Martijn; Lutgens, Ludovicus; Reniers, Brigitte; Jürgenliemk-Schulz, Ina Maria

    2013-01-01

    Background and purpose: To compare MRI-guided treatment planning approaches between four centres that use tandem-ovoid applicators. Material and methods: Four centres generated three treatment plans for four patients: standard, optimised intracavitary, and optimised intracavitary/interstitial. Prescribed D90 High-Risk CTV (HR-CTV) was 85 Gy EQD2 (external-beam radiotherapy and brachytherapy), while the D 2cc OAR limit was 90 Gy EQD2 for bladder and 75 Gy EQD2 for rectum, sigmoid, and bowel, respectively. DVH-parameters, source loading patterns and spatial dose distributions of the three treatment plans were compared. Results: The standard plans of the different centres were comparable with respect to the D90 HR-CTV, but differed in OAR doses. MRI-guided intracavitary optimisation resulted in organ sparing and smaller variation in DVH parameters between the centres. Adding interstitial needles led to target dose escalation while respecting the OAR constraints. However, substantial differences in relative weights of the applicator parts resulted in an increased variation in DVH parameters and locations of high dose regions. Conclusions: MRI-guided brachytherapy treatment planning optimisation provides the possibility to increase the dose to the HR-CTV and spare the OARs. Depending on the degree of conformity the centres make different choices in relative weighting of applicator parts, leading to different dose distributions

  9. Positional variation of applicators during low dose rate intracavitary brachytherapy for cervical cancer: a prospective study

    Directory of Open Access Journals (Sweden)

    Arul Ponni

    2010-10-01

    Full Text Available Purpose: In order to know the effect of variation in position of applicators to the dose received by the tumor volume, critical organs such as rectum and bladder and the correlation of variation on the clinical outcome.Material and methods: 36 patients with histologically proven cervical cancer, undergoing intracavitary brachythe - rapy (ICBT from October 2005 to December 2006 were the subjects of the study. Two pairs of orthogonal X-ray films were taken: one prior to loading of sources and the other after removal of sources. These patients were followed up as per the RTOG criteria.Results: The median duration of insertion was 25 hours with a median follow up period of 6.7 months. The translational variation of the applicator position for all patients was 3 mm and 1 mm (2 SD, respectively, in the patient’s lateral and antero-posterior direction. The rotational variation was 3 and 4 degrees (2 SD in the patient’s transverse and sagittal planes. Detailed analysis of source movement showed following changes in median dose: point A: 14%, point B: 2%, point P: 1%, Rectum 1: 3.5%, Rectum 2: 4% and Bladder: 9.1%. The incidence of rectal toxicity was 6/36(16.7% and that of bladder was 1/36 (2.8%. When the variables were grouped to evaluate the relationship, our study showed statistically significant relationship between: R2 and rectal toxicity (p value: 0.002, point A and rectal toxicity (Pearson: 0.792, lateral displacement/anteroposterior displacement and rectal toxicity (p value: 0.012/0.003, beta angle and R2 (p value: 0.002.Conclusions: The geometric relationships between the ICBT applicators and the critical structures vary during the course of low dose rate brachytherapy. Source movement does result in significant dose alterations in terms of increased rate of complications, but its impact on cure rates needs to be studied in the future.

  10. Clinical Use of the Utrecht Applicator for Combined Intracavitary/Interstitial Brachytherapy Treatment in Locally Advanced Cervical Cancer

    International Nuclear Information System (INIS)

    Nomden, Christel N.; Leeuw, Astrid A.C. de; Moerland, Marinus A.; Roesink, Judith M.; Tersteeg, Robbert J.H.A.; Jürgenliemk-Schulz, Ina Maria

    2012-01-01

    Purpose: The aims of this study were to investigate the benefit of the Utrecht interstitial CT/MR applicator for combined intracavitary/interstitial (IC/IS) approach, using magnetic resonance imaging—guided brachytherapy, over the intracavitary approach alone in patients with locally advanced cervical cancer and to analyze the clinical use of needles. Methods and Materials: This study includes the first 20 patients treated with the new applicator. Brachytherapy consisted of two pulsed dose rate applications, and the second application was performed with the IC/IS approach. The number of needles, chosen guiding holes through the ovoids, and insertion depths were based on the dose distribution and dosimetric shortcomings of the first application (IC alone). We investigated the dosimetric gain by comparing the clinical interstitial optimized plan (IC/IS clinical ) with an additionally generated optimized plan without needle use (IC study ). Furthermore, we studied the relation of the inserted needles and their source loading patterns with the high-risk clinical target volume (HR-CTV). Results: A total of 54 needles (range, 1–6 per application) were applied with an average depth of 25 mm. The chosen needle positions corresponded with the location of the HR-CTV extensions. The total and individual needle treatment times per application were on average 19% (range, 4–35%) and 7% (range, 2–14%) of the implant treatment time, respectively. The total (external-beam radiotherapy + brachytherapy) D90 HR-CTV for the IC study and the IC/IS clinical were on average 79.5 (SD 7.4) Gy α/β10 and 83.9 (SD 6.7) Gy α/β10 , respectively, with an average gain of 4.4 (SD 2.3) Gy α/β10 for the second application. Conclusions: Needle placement was feasible in all patients and resulted in a gain in dose and better coverage of HR-CTV. Defining the location of HR-CTV protrusions and analyzing the associated needles has given us deeper understanding of the possibilities in magnetic

  11. SU-G-201-07: Dosimetric Verification of a 3D Printed HDR Skin Brachytherapy Applicator

    Energy Technology Data Exchange (ETDEWEB)

    Rasmussen, K; Stanley, D; Eng, T; Kirby, N; Gutierrez, A; Stathakis, S; Papanikolaou, N [University of Texas HSC SA, San Antonio, TX (United States); Baumgarten, A; Pelletier, C; Jung, J; Feng, Y; Huang, Z; Ju, A [East Carolina University, Greenville, NC (United States); Corbett, M [Greenville Health System, Greenville, SC (United States)

    2016-06-15

    Purpose: The use of radiation as a treatment modality for skin cancer has increased significantly over the last decade with standardized applicators. Utilizing 3D printing, the ability to make applicators specifically designed for each patient’s anatomy has become economically feasible. With this in mind it was the aim of this study to determine the dosimetric accuracy of a 3-D printed HDR brachytherapy applicator for the skin. Methods: A CT reference image was used to generate a custom applicator based on an anthropomorphic head and neck phantom. To create the applicator a 1cm expansion anteriorly with 0.5cmX0.5cm trenches on the outer surface that were spaced 1cm sup-inf to accommodate standard 6F flexible catheters. The applicator was printed using PLA material using a printrbot simple printer. A treatment plan optimized to deliver a clinically representative volume was created in Oncentra and delivered with a nucletron afterloader. Measurements were made using TLDs and EBT3 gafchromic film that were placed between the applicator and the phantom’s forehead. An additional piece of film was also used to qualitatively asses the dose distribution in the transverse plane. Using a standard vaginal cylinder and bolus, a standardized curve correlating TLD and film exposure-to-radiation dose was established by irradiating film to known doses (200,500,700 cGy) at a 3.5 cm radius distance. Results: Evaluated TLDs showed the absolute dose delivered to the skin surface using the 3-D printed bolus was 615cGy±6%, with a mean predicted TPS value in the measured area of 617.5±7%. Additionally, planar dose distributions had good qualitative agreement with calculated TPS isodoses. Conclusion: This work demonstrates patient specific 3-D printed HDR brachytherapy applicators for skin cancer treatments are practical and accurate in TPS calculations but additional measurements are needed to verify additional sites and dose at depth.

  12. Investigation of Anisotropy Caused by Cylinder Applicator on Dose Distribution around Cs-137 Brachytherapy Source using MCNP4C Code

    Directory of Open Access Journals (Sweden)

    Sedigheh Sina

    2011-06-01

    Full Text Available Introduction: Brachytherapy is a type of radiotherapy in which radioactive sources are used in proximity of tumors normally for treatment of malignancies in the head, prostate and cervix. Materials and Methods: The Cs-137 Selectron source is a low-dose-rate (LDR brachytherapy source used in a remote afterloading system for treatment of different cancers. This system uses active and inactive spherical sources of 2.5 mm diameter, which can be used in different configurations inside the applicator to obtain different dose distributions. In this study, first the dose distribution at different distances from the source was obtained around a single pellet inside the applicator in a water phantom using the MCNP4C Monte Carlo code. The simulations were then repeated for six active pellets in the applicator and for six point sources.  Results: The anisotropy of dose distribution due to the presence of the applicator was obtained by division of dose at each distance and angle to the dose at the same distance and angle of 90 degrees. According to the results, the doses decreased towards the applicator tips. For example, for points at the distances of 5 and 7 cm from the source and angle of 165 degrees, such discrepancies reached 5.8% and 5.1%, respectively.  By increasing the number of pellets to six, these values reached 30% for the angle of 5 degrees. Discussion and Conclusion: The results indicate that the presence of the applicator causes a significant dose decrease at the tip of the applicator compared with the dose in the transverse plane. However, the treatment planning systems consider an isotropic dose distribution around the source and this causes significant errors in treatment planning, which are not negligible, especially for a large number of sources inside the applicator.

  13. SU-G-201-07: Dosimetric Verification of a 3D Printed HDR Skin Brachytherapy Applicator

    International Nuclear Information System (INIS)

    Rasmussen, K; Stanley, D; Eng, T; Kirby, N; Gutierrez, A; Stathakis, S; Papanikolaou, N; Baumgarten, A; Pelletier, C; Jung, J; Feng, Y; Huang, Z; Ju, A; Corbett, M

    2016-01-01

    Purpose: The use of radiation as a treatment modality for skin cancer has increased significantly over the last decade with standardized applicators. Utilizing 3D printing, the ability to make applicators specifically designed for each patient’s anatomy has become economically feasible. With this in mind it was the aim of this study to determine the dosimetric accuracy of a 3-D printed HDR brachytherapy applicator for the skin. Methods: A CT reference image was used to generate a custom applicator based on an anthropomorphic head and neck phantom. To create the applicator a 1cm expansion anteriorly with 0.5cmX0.5cm trenches on the outer surface that were spaced 1cm sup-inf to accommodate standard 6F flexible catheters. The applicator was printed using PLA material using a printrbot simple printer. A treatment plan optimized to deliver a clinically representative volume was created in Oncentra and delivered with a nucletron afterloader. Measurements were made using TLDs and EBT3 gafchromic film that were placed between the applicator and the phantom’s forehead. An additional piece of film was also used to qualitatively asses the dose distribution in the transverse plane. Using a standard vaginal cylinder and bolus, a standardized curve correlating TLD and film exposure-to-radiation dose was established by irradiating film to known doses (200,500,700 cGy) at a 3.5 cm radius distance. Results: Evaluated TLDs showed the absolute dose delivered to the skin surface using the 3-D printed bolus was 615cGy±6%, with a mean predicted TPS value in the measured area of 617.5±7%. Additionally, planar dose distributions had good qualitative agreement with calculated TPS isodoses. Conclusion: This work demonstrates patient specific 3-D printed HDR brachytherapy applicators for skin cancer treatments are practical and accurate in TPS calculations but additional measurements are needed to verify additional sites and dose at depth.

  14. Dosimetric comparison of different dose prescription systems with CT based intracavitary brachytherapy and manual back projection technique to reconstruct the applicator

    International Nuclear Information System (INIS)

    Oinam, A.S.; Dubey, S.; Kehwar, T.S.; Rout, Sanjaya K.; Patel, F.D.; Sharma, S.C.; Goyal, D.R.; Narayan, P.

    2002-01-01

    Intracavitary brachytherapy is one of the well-established techniques for the treatment of carcinoma of cervix. The prediction of late effect of normal tissue like rectum and bladder needs the defining of the volume of the bladder and rectum in situ. In the normal planning of intracavitary and interstitial implants, simulated radiograph films are used to reconstruct the applicator geometry and dose points to represent the dose to critical organs. CT based brachytherapy can define such volume instead of defining dose points, which represent the dose to these critical organs

  15. Brachytherapy, diagnostic radiology, mammographic radiology and ophthalmic applicators. An assessment of current and future needs in the UK and the role of NPL

    International Nuclear Information System (INIS)

    Angliss, R.; Bass, G.; Sander, T.

    2001-01-01

    Several UK hospitals were visited by NPL staff to discuss the current practises and future developments in brachytherapy, diagnostic and mammographic radiology and ophthalmic applicators. The results of the discussions are presented here, including NPL's role in each of these areas is discussed. (author)

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2014-05-15

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

  17. Application of Gafchromic registered film in the dosimetry of an intravascular brachytherapy source

    International Nuclear Information System (INIS)

    Song Haijun; Roa, D. Eduardo; Yue Ning; D'Errico, Francesco; Chen Zhe; Nath, Ravinder

    2006-01-01

    The methodology of brachytherapy source dosimetry with Gafchromic registered MD 55-2 film (ISP Technologies, Inc.) is examined with an emphasis on the nonlinearity of the optical density-dose relation within the dynamic dose range, the radial distance-dependent measurement uncertainty, and the format of data presentation. The specific source chosen for this study was a Checkmate trade mark sign (Cordis Corporation) intravascular brachytherapy system. The two-dimensional dose distribution around the source was characterized by a comprehensive analysis of measurement uncertainties. A comparative analysis of the dosimetric data from the vendor and from the scientific literature showed a substantial consistency of the information available for the Checkmate trade mark sign source. Our two-dimensional dosimetric data for the Checkmate trade mark sign source trains is presented in the form of measured along and away dose tables

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

    Energy Technology Data Exchange (ETDEWEB)

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

    1999-12-31

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

  19. Aspects of the application of complementary brachytherapy for early invasive breast cancer

    Energy Technology Data Exchange (ETDEWEB)

    Homma, L.A.H. [Universidade Federal de Minas Gerais (UFMG), Belo Horizonte, MG (Brazil). Programa de Pos-Graduacao em Ciencias e Tecnicas Nucleares; Universidade Federal de Minas Gerais (UFMG), Belo Horizonte, MG (Brazil). Hospital das Clinicas]. E-mail: luciahomma@terra.com.br; Campos, T.P.R. [Universidade Federal de Minas Gerais (UFMG), Belo Horizonte, MG (Brazil). Programa de Pos-Graduacao em Ciencias e Tecnicas Nucleares]. E-mail: campos@nuclear.ufmg.br; Silva, S.Z.C. [Universidade Federal de Minas Gerais (UFMG), Belo Horizonte, MG (Brazil). Hospital das Clinicas; Lima, C.F. [ECOGRAF, Belo Horizonte, MG (Brazil). Nucleo de Diagnostico

    2007-07-01

    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/r{sup 2}, 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 Ir{sup 192} was simulated through the development of a computerized digital voxels phantom, which represented the breast anatomy. The Monte Carlo Code (MCNP {sup 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. Aspects of the application of complementary brachytherapy for early invasive breast cancer

    International Nuclear Information System (INIS)

    Homma, L.A.H.; Universidade Federal de Minas Gerais; Campos, T.P.R.; Silva, S.Z.C.; Lima, C.F.

    2007-01-01

    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/r 2 , 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 Ir 192 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)

  1. SU-E-J-216: A Sequence Independent Approach for Quantification of MR Image Deformations From Brachytherapy Applicators

    Energy Technology Data Exchange (ETDEWEB)

    Wieringen, N van; Heerden, L van; Gurney-Champion, O; Kesteren, Z van; Houweling, A; Pieters, B; Bel, A [Academic Medical Center, Amsterdam (Netherlands)

    2015-06-15

    Purpose: MRI is increasingly used as a single imaging modality for brachytherapy treatment planning. The presence of a brachytherapy applicator may cause distortions in the images, especially at higher field strengths. Our aim is to develop a procedure to quantify these distortions theoretically for any MR-sequence and to verify the estimated deformations for clinical sequences. Methods: Image distortions due to perturbation of the B0-field are proportional to the ratio of the induced frequency shift and the read-out bandwidth of the applied sequence. By reconstructing a frequency-shift map from the phase data from a multi-echo sequence, distortions can be calculated for any MR-sequence. Verification of this method for estimating distortions was performed by acquiring images with opposing read-out directions and consequently opposing distortions. The applicator shift can be determined by rigidly matching these images. Clinically, T2W-TSE-images are used for this purpose. For pre-clinical tests, EPI-sequences with narrow read-out bandwidth (19.5–47.5Hz), consequently large distortions, were added to the set of clinical MRsequences. To quantify deformations of the Utrecht Interstitial CT/MR applicator (Elekta Brachytherapy) on a Philips Ingenia 3T MRI, pre-clinical tests were performed in a phantom with the applicator in water, followed by clinical validation. Results: Deformations observed in the narrow bandwidth EPI-images were well predicted using the frequency-shift, the latter giving an overestimation up to 30%/up to 1 voxel. For clinically applied MR-sequences distortions were well below the voxel size. In patient setup distortions determined from the frequency-shift map were at sub-voxel level (<0.7mm). Using T2W-images larger distortions were found (1–2mm). This discrepancy was caused by patient movement between/during acquisition of the T2W-images with opposing read-out directions. Conclusion: Phantom experiments demonstrated the feasibility of a

  2. Towards clinical application of RayStretch for heterogeneity corrections in LDR permanent 125I prostate brachytherapy.

    Science.gov (United States)

    Hueso-González, Fernando; Ballester, Facundo; Perez-Calatayud, Jose; Siebert, Frank-André; Vijande, Javier

    RayStretch is a simple algorithm proposed for heterogeneity corrections in low-dose-rate brachytherapy. It is built on top of TG-43 consensus data, and it has been validated with Monte Carlo (MC) simulations. In this study, we take a real clinical prostate implant with 71 125 I seeds as reference and we apply RayStretch to analyze its performance in worst-case scenarios. To do so, we design two cases where large calcifications are located in the prostate lobules. RayStretch resilience under various calcification density values is also explored. Comparisons against MC calculations are performed. Dose-volume histogram-related parameters like prostate D 90 , rectum D 2cc , or urethra D 10 obtained with RayStretch agree within a few percent with the detailed MC results for all cases considered. The robustness and compatibility of RayStretch with commercial treatment planning systems indicate its applicability in clinical practice for dosimetric corrections in prostate calcifications. Its use during intraoperative ultrasound planning is foreseen. Copyright © 2017 American Brachytherapy Society. Published by Elsevier Inc. All rights reserved.

  3. Posttraumatic Stress Disorder After High-Dose-Rate Brachytherapy for Cervical Cancer With 2 Fractions in 1 Application Under Spinal/Epidural Anesthesia: Incidence and Risk Factors

    Energy Technology Data Exchange (ETDEWEB)

    Kirchheiner, Kathrin, E-mail: kathrin.kirchheiner@meduniwien.ac.at [Department of Radiation Oncology, Comprehensive Cancer Center, Medical University of Vienna/General Hospital of Vienna, Vienna (Austria); Christian Doppler Laboratory for Medical Radiation Research for Radiation Oncology, Medical University of Vienna, Vienna (Austria); Czajka-Pepl, Agnieszka [Department of Radiation Oncology, Comprehensive Cancer Center, Medical University of Vienna/General Hospital of Vienna, Vienna (Austria); Ponocny-Seliger, Elisabeth [Department of Psychology, Sigmund Freud Private University Vienna, Vienna (Austria); Scharbert, Gisela; Wetzel, Léonore [Department of Anaesthesia, General Intensive Care and Pain Management, Medical University of Vienna/General Hospital of Vienna, Vienna (Austria); Nout, Remi A. [Department of Clinical Oncology, Leiden University Medical Center, Leiden (Netherlands); Sturdza, Alina [Department of Radiation Oncology, Comprehensive Cancer Center, Medical University of Vienna/General Hospital of Vienna, Vienna (Austria); Dimopoulos, Johannes C. [Metropolitan Hospital, Athens (Greece); Dörr, Wolfgang; Pötter, Richard [Department of Radiation Oncology, Comprehensive Cancer Center, Medical University of Vienna/General Hospital of Vienna, Vienna (Austria); Christian Doppler Laboratory for Medical Radiation Research for Radiation Oncology, Medical University of Vienna, Vienna (Austria)

    2014-06-01

    Purpose: To investigate the psychological consequences of high-dose-rate brachytherapy with 2 fractions in 1 application under spinal/epidural anesthesia in the treatment of locally advanced cervical cancer. Methods and Materials: In 50 patients with locally advanced cervical cancer, validated questionnaires were used for prospective assessment of acute and posttraumatic stress disorder (ASD/PTSD) (Impact of Event Scale–Revision), anxiety/depression (Hospital Anxiety and Depression Scale), quality of life (European Organization for Research and Treatment of Cancer Quality of Life Questionnaire Core 30/Cervical Cancer 24), physical functioning (World Health Organization performance status), and pain (visual analogue scale), before and during treatment and 1 week and 3 months after treatment. Qualitative interviews were recorded in open format for content analysis. Results: Symptoms of ASD occurred in 30% of patients 1 week after treatment; and of PTSD in 41% 3 months after treatment in association with this specific brachytherapy procedure. Pretreatment predictive variables explain 82% of the variance of PTSD symptoms. Helpful experiences were the support of the treatment team, psychological support, and a positive attitude. Stressful factors were pain, organizational problems during treatment, and immobility between brachytherapy fractions. Conclusions: The specific brachytherapy procedure, as performed in the investigated mono-institutional setting with 2 fractions in 1 application under spinal/epidural anesthesia, bears a considerable risk of traumatization. The source of stress seems to be not the brachytherapy application itself but the maintenance of the applicator under epidural anesthesia in the time between fractions. Patients at risk may be identified before treatment, to offer targeted psycho-social support. The patients' open reports regarding helpful experiences are an encouraging feedback for the treatment team; the reported stressful

  4. Posttraumatic Stress Disorder After High-Dose-Rate Brachytherapy for Cervical Cancer With 2 Fractions in 1 Application Under Spinal/Epidural Anesthesia: Incidence and Risk Factors

    International Nuclear Information System (INIS)

    Kirchheiner, Kathrin; Czajka-Pepl, Agnieszka; Ponocny-Seliger, Elisabeth; Scharbert, Gisela; Wetzel, Léonore; Nout, Remi A.; Sturdza, Alina; Dimopoulos, Johannes C.; Dörr, Wolfgang; Pötter, Richard

    2014-01-01

    Purpose: To investigate the psychological consequences of high-dose-rate brachytherapy with 2 fractions in 1 application under spinal/epidural anesthesia in the treatment of locally advanced cervical cancer. Methods and Materials: In 50 patients with locally advanced cervical cancer, validated questionnaires were used for prospective assessment of acute and posttraumatic stress disorder (ASD/PTSD) (Impact of Event Scale–Revision), anxiety/depression (Hospital Anxiety and Depression Scale), quality of life (European Organization for Research and Treatment of Cancer Quality of Life Questionnaire Core 30/Cervical Cancer 24), physical functioning (World Health Organization performance status), and pain (visual analogue scale), before and during treatment and 1 week and 3 months after treatment. Qualitative interviews were recorded in open format for content analysis. Results: Symptoms of ASD occurred in 30% of patients 1 week after treatment; and of PTSD in 41% 3 months after treatment in association with this specific brachytherapy procedure. Pretreatment predictive variables explain 82% of the variance of PTSD symptoms. Helpful experiences were the support of the treatment team, psychological support, and a positive attitude. Stressful factors were pain, organizational problems during treatment, and immobility between brachytherapy fractions. Conclusions: The specific brachytherapy procedure, as performed in the investigated mono-institutional setting with 2 fractions in 1 application under spinal/epidural anesthesia, bears a considerable risk of traumatization. The source of stress seems to be not the brachytherapy application itself but the maintenance of the applicator under epidural anesthesia in the time between fractions. Patients at risk may be identified before treatment, to offer targeted psycho-social support. The patients' open reports regarding helpful experiences are an encouraging feedback for the treatment team; the reported stressful

  5. MR guided applicator reconstruction for brachytherapy of cervical cancer using the novel titanium Rotterdam applicator

    International Nuclear Information System (INIS)

    Petit, Steven; Wielopolski, Piotr; Rijnsdorp, Reneé; Mens, Jan-Willem; Kolkman-Deurloo, Inger-Karine

    2013-01-01

    A novel model of the titanium Rotterdam tandem and ovoid applicator is presented. As titanium produces artefacts in MR images, an MR sequence was sought and optimised for visualisation and accurate applicator reconstruction. The mean inter-observer (8 observers) variability for four patients was only 0.7 mm (maximum 1.7 mm)

  6. TU-AB-BRC-08: Egs-brachy, a Fast and Versatile Monte Carlo Code for Brachytherapy Applications

    Energy Technology Data Exchange (ETDEWEB)

    Chamberland, M; Taylor, R; Rogers, D; Thomson, R [Carleton University, Ottawa, ON (Canada)

    2016-06-15

    Purpose: To introduce egs-brachy, a new, fast, and versatile Monte Carlo code for brachytherapy applications. Methods: egs-brachy is an EGSnrc user-code based on the EGSnrc C++ class library (egs++). Complex phantom, applicator, and source model geometries are built using the egs++ geometry module. egs-brachy uses a tracklength estimator to score collision kerma in voxels. Interaction, spectrum, energy fluence, and phase space scoring are also implemented. Phase space sources and particle recycling may be used to improve simulation efficiency. HDR treatments (e.g. stepping source through dwell positions) can be simulated. Standard brachytherapy seeds, as well as electron and miniature x-ray tube sources are fully modelled. Variance reduction techniques for electron source simulations are implemented (Bremsstrahlung cross section enhancement, uniform Bremsstrahlung splitting, and Russian Roulette). TG-43 parameters of seeds are computed and compared to published values. Example simulations of various treatments are carried out on a single 2.5 GHz Intel Xeon E5-2680 v3 processor core. Results: TG-43 parameters calculated with egs-brachy show excellent agreement with published values. Using a phase space source, 2% average statistical uncertainty in the PTV ((2mm){sup 3} voxels) can be achieved in 10 s for 100 {sup 125}I or {sup 103}Pd seeds in a 36.2 cm{sup 3} prostate PTV, 31 s for 64 {sup 103}Pd seeds in a 64 cm{sup 3} breast PTV, and 56 s for a miniature x-ray tube in a 27 cm{sup 3} breast PTV. Comparable uncertainty is reached in 12 s in a (1 mm){sup 3} water voxel 5 mm away from a COMS 16mm eye plaque with 13 {sup 103}Pd seeds. Conclusion: The accuracy of egs-brachy has been demonstrated through benchmarking calculations. Calculation times are sufficiently fast to allow full MC simulations for routine treatment planning for diverse brachytherapy treatments (LDR, HDR, miniature x-ray tube). egs-brachy will be available as free and open-source software to the

  7. TU-AB-BRC-08: Egs-brachy, a Fast and Versatile Monte Carlo Code for Brachytherapy Applications

    International Nuclear Information System (INIS)

    Chamberland, M; Taylor, R; Rogers, D; Thomson, R

    2016-01-01

    Purpose: To introduce egs-brachy, a new, fast, and versatile Monte Carlo code for brachytherapy applications. Methods: egs-brachy is an EGSnrc user-code based on the EGSnrc C++ class library (egs++). Complex phantom, applicator, and source model geometries are built using the egs++ geometry module. egs-brachy uses a tracklength estimator to score collision kerma in voxels. Interaction, spectrum, energy fluence, and phase space scoring are also implemented. Phase space sources and particle recycling may be used to improve simulation efficiency. HDR treatments (e.g. stepping source through dwell positions) can be simulated. Standard brachytherapy seeds, as well as electron and miniature x-ray tube sources are fully modelled. Variance reduction techniques for electron source simulations are implemented (Bremsstrahlung cross section enhancement, uniform Bremsstrahlung splitting, and Russian Roulette). TG-43 parameters of seeds are computed and compared to published values. Example simulations of various treatments are carried out on a single 2.5 GHz Intel Xeon E5-2680 v3 processor core. Results: TG-43 parameters calculated with egs-brachy show excellent agreement with published values. Using a phase space source, 2% average statistical uncertainty in the PTV ((2mm)"3 voxels) can be achieved in 10 s for 100 "1"2"5I or "1"0"3Pd seeds in a 36.2 cm"3 prostate PTV, 31 s for 64 "1"0"3Pd seeds in a 64 cm"3 breast PTV, and 56 s for a miniature x-ray tube in a 27 cm"3 breast PTV. Comparable uncertainty is reached in 12 s in a (1 mm)"3 water voxel 5 mm away from a COMS 16mm eye plaque with 13 "1"0"3Pd seeds. Conclusion: The accuracy of egs-brachy has been demonstrated through benchmarking calculations. Calculation times are sufficiently fast to allow full MC simulations for routine treatment planning for diverse brachytherapy treatments (LDR, HDR, miniature x-ray tube). egs-brachy will be available as free and open-source software to the medical physics research community. This

  8. The use of laminarias for osmotic dilation of the cervix in gynecological brachytherapy applications

    International Nuclear Information System (INIS)

    Mayr, Nina A.; Sorosky, Joel I.; Zhen Weining; Weidner, Geoffrey J.; Hussey, David H.; Anderson, Barrie; Buller, Richard E.

    1998-01-01

    Purpose: Osmotic dilators (laminarias) have been used for gradual nontraumatic dilation of the cervical canal for various intrauterine procedures; however, this technique has not been well accepted in gynecological brachytherapy. The purpose of this study was to evaluate the efficacy of osmotic cervical dilation for brachytherapy in gynecologic cancer patients, without the use of general/regional anesthesia, and to assess patient tolerance, complications, and outcome. Methods and Materials: Thirteen brachytherapy procedures were performed in 6 patients with clinical Stages I and II endometrial (5) and Stage IB cervical cancer (1), who were unable to tolerate general/regional anesthesia because of severe medical problems. An osmotic dilator (synthetic laminaria) was inserted into the cervical os 10-12 h before each brachytherapy procedure and removed just before the procedure. Standard Fletcher-Suit-Delclos tandem insertions with vaginal colpostats or cylinders were then performed. Degree of cervical dilation, patient discomfort, procedure time, intra- and postoperative complications were recorded, and local control and survival were assessed. Median follow-up was 31 months (range: 8-35 months). Results: The diameter of the dilated cervical os after laminaria removal was adequate (≥ 5 mm) for tandem insertion, and no additional mechanical dilation was required in all but one procedure (1 of 13). All procedures were performed without general/regional anesthesia. The mean duration of the procedures was 44 min (range, 20-60 min). Discomfort was minimal in all cases. There were no intra- or postoperative complications. All patients maintained local control until death (1 of metastatic disease, 2 of intercurrent disease) or last follow-up (2 with no evidence of disease, 1 alive with metastatic disease). Conclusion: This preliminary study suggests that osmotic cervical dilation with a synthetic laminaria is a useful technique to facilitate intrauterine tandem insertion

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

    Energy Technology Data Exchange (ETDEWEB)

    Lacerda, Kassio Andre; Lameiras, Fernando Soares [Centro de Desenvolvimento da Tecnologia Nuclear, (CDTN/CNEN-MG), Belo Horizonte, MG (Brazil); Silva, Viviane Viana [Centro de Desenvolvimento da Tecnologia Nuclear, (CDTN/CNEN-MG), Belo Horizonte, MG (Brazil); Universidade Vale do Rio Verde de Tres Coracoes, MG (Brazil)

    2007-07-15

    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. (author)

  10. Improved electromagnetic tracking for catheter path reconstruction with application in high-dose-rate brachytherapy.

    Science.gov (United States)

    Lugez, Elodie; Sadjadi, Hossein; Joshi, Chandra P; Akl, Selim G; Fichtinger, Gabor

    2017-04-01

    measurements (3.5 mm) by 46%. Similarly, with a path reconstruction precision of 0.8 mm, the nonholonomic EKF surpassed the performance of the manufacturer's filters (1.0 mm) by 20% and the raw EM measurements (1.7 mm) by 53%. Path reconstruction accuracies did not follow an apparent trend when varying the path curvature and sensor velocity; instead, reconstruction accuracies were predominantly impacted by the position of the EM field transmitter ([Formula: see text]). The advanced nonholonomic EKF is effective in reducing EM measurement errors when reconstructing catheter paths, is robust to path curvature and sensor speed, and runs in real time. Our approach is promising for a plurality of clinical procedures requiring catheter reconstructions, such as cardiovascular interventions, pulmonary applications (Bender et al. in medical image computing and computer-assisted intervention-MICCAI 99. Springer, Berlin, pp 981-989, 1999), and brachytherapy.

  11. Optimal application of the Contura multilumen balloon breast brachytherapy catheter vacuum port to deliver accelerated partial breast irradiation.

    Science.gov (United States)

    Tokita, Kenneth M; Cuttino, Laurie W; Vicini, Frank A; Arthur, Douglas W; Todor, Dorin A; Julian, Thomas B; Lyden, Maureen R

    2011-01-01

    The impact of using the Contura multilumen balloon (MLB) (SenoRx, Inc., Irvine, CA) breast brachytherapy catheter's vacuum port in patients treated with accelerated partial breast irradiation (APBI) was analyzed. Data from 32 patients at two sites were reviewed. Variables analyzed included the seroma fluid (SF):air volume around the MLB before and after vacuum port use and on its ability to improve (1) the eligibility of patients for APBI and (2) dose coverage of the planning target volume for evaluation (PTV_EVAL) in eligible patients. The median SF/air volume before vacuum removal was 6.8 cc vs. 0.8 cc after vacuum removal (median reduction in SF/air volume was 90.5%). Before vacuum port use, the median SF/air volume expressed as percentage of the PTV_EVAL was 7.8% (range, 1.9-26.6) in all patients. After application of the vacuum, this was reduced to 1.2%. Before vacuum port use, 10 (31.3%) patients were not considered acceptable candidates for APBI because the SF/air volume:PTV_EVAL ratio (SF:PTV) was greater than 10% (range, 10.1-26.6%; median, 15.2%). After vacuum port use, the median SF:PTV ratio was 1.6% for a median reduction of 91.5%. In addition, the percentage of the prescribed dose covering greater than or equal to 90% of the PTV_EVAL proportionally increased a median of 8% (range, 3-10%) in eligible patients. Use of the Contura MLB vacuum port significantly improved the conformity of the target tissue to the balloon surface, leading to reproducible dose delivery and increased target volume coverage. In addition, application of the vacuum allowed the safe treatment of unacceptable patients with APBI. Copyright © 2011 American Brachytherapy Society. Published by Elsevier Inc. All rights reserved.

  12. 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)

    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.

    2013-01-01

    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)

  13. SU-E-T-232: Custom High-Dose-Rate Brachytherapy Surface Mold Applicators: The Importance Source to Skin Distance

    International Nuclear Information System (INIS)

    Park, S; Demanes, J; Kamrava, M

    2015-01-01

    Purpose: Surface mold applicators can be customized to fit irregular skin surfaces that are difficult to treat with other radiation therapy techniques. Optimal design of customized HDR skin brachytherapy is not well-established. We evaluated the impact of applicator thickness (source to skin distance) on target dosimetry. Methods: 27 patients had 34 treated sites: scalp 4, face 13, extremity 13, and torso 4. Custom applicators were constructed from 5–15 mm thick thermoplastic bolus molded over the skin lesion. A planar array of plastic brachytherapy catheters spaced 5–10 mm apart was affixed to the bolus. CT simulation was used to contour the target volume and to determine the prescription depth. Inverse planning simulated annealing followed by graphical optimization was used to plan and deliver 40–56 Gy in 8–16 fractions. Target coverage parameters (D90, Dmean, and V100) and dose uniformity (V110–200, D0.1cc, D1cc, and D2cc) were studied according to target depth (<5mm vs. ≥5mm) and applicator thickness (5–10mm vs. ≥10mm). Results: The average prescription depth was 4.2±1.5mm. The average bolus thickness was 9.2±2.4mm. The median CTV volume was 10.0 cc (0.2–212.4 cc). Similar target coverage was achieved with prescription depths of <5mm and ≥5mm (Dmean = 113.8% vs. 112.4% and D90 = 100.2% vs. 98.3%). The <5mm prescription depth plans were more uniform (D0.1cc = 131.8% vs. 151.8%). Bolus thickness <10mm vs. ≥10mm plans also had similar target coverage (Dmean = 118.2% vs. 110.7% and D90 = 100.1% vs. 99.0%). Applicators ≥10mm thick, however, provide more uniform target dosimetry (D0.1cc = 146.9% vs. 139.5%). Conclusion: Prescription depth is based upon the thickness of the lesion and upon the clinical needs of the patient. Applicators ≥10mm thick provide more dose uniformity than 5–10mm thick applicators. Applicator thickness is an important variable that should be considered during treatment planning to achieve optimal dose uniformity

  14. Applicability and dosimetric impact of ultrasound-based preplanning in high-dose-rate brachytherapy of prostate cancer

    International Nuclear Information System (INIS)

    Aebersold, D.M.; Isaak, B.; Behrensmeier, F.; Kolotas, C.; Mini, R.; Greiner, R.H.; Thalmann, G.; Kranzbuehler, H.

    2004-01-01

    Background and purpose: analyses of permanent brachytherapy seed implants of the prostate have demonstrated that the use of a preplan may lead to a considerable decrease of dosimetric implant quality. The authors aimed to determine whether the same drawbacks of preplanning also apply to high-dose-rate (HDR) brachytherapy. Patients and methods: 15 patients who underwent two separate HDR brachytherapy implants in addition to external-beam radiation therapy for advanced prostate cancer were analyzed. A pretherapeutic transrectal ultrasound was performed in all patients to generate a preplan for the first brachytherapy implant. For the second brachytherapy, a subset of patients were treated by preplans based on the ultrasound from the first brachytherapy implant. Preplans were compared with the respective postplans assessing the following parameters: coverage index, minimum target dose, homogeneity index, and dose exposure of organs at risk. The prostate geometries (volume, width, height, length) were compared as well. Results: at the first brachytherapy, the matching between the preplan and actual implant geometry was sufficient in 47% of the patients, and the preplan could be applied. The dosimetric implant quality decreased considerably: the mean coverage differed by -0.11, the mean minimum target dose by -0.15, the mean homogeneity index by -0.09. The exposure of organs at risk was not substantially altered. At the second brachytherapy, all patients could be treated by the preplan; the differences between the implant quality parameters were less pronounced. The changes of prostate geometry between preplans and postplans were considerable, the differences in volume ranging from -8.0 to 13.8 cm 3 and in dimensions (width, height, length) from -1.1 to 1.0 cm. Conclusion: preplanning in HDR brachytherapy of the prostate is associated with a substantial decrease of dosimetric implant quality, when the preplan is based on a pretherapeutic ultrasound. The implant quality

  15. Assessment of ocular beta radiation dose distribution due to 106Ru/106Rh brachytherapy applicators using MCNPX Monte Carlo code

    Directory of Open Access Journals (Sweden)

    Nilseia Aparecida Barbosa

    2014-08-01

    Full Text Available Purpose: Melanoma at the choroid region is the most common primary cancer that affects the eye in adult patients. Concave ophthalmic applicators with 106Ru/106Rh beta sources are the more used for treatment of these eye lesions, mainly lesions with small and medium dimensions. The available treatment planning system for 106Ru applicators is based on dose distributions on a homogeneous water sphere eye model, resulting in a lack of data in the literature of dose distributions in the eye radiosensitive structures, information that may be crucial to improve the treatment planning process, aiming the maintenance of visual acuity. Methods: The Monte Carlo code MCNPX was used to calculate the dose distribution in a complete mathematical model of the human eye containing a choroid melanoma; considering the eye actual dimensions and its various component structures, due to an ophthalmic brachytherapy treatment, using 106Ru/106Rh beta-ray sources. Two possibilities were analyzed; a simple water eye and a heterogeneous eye considering all its structures. Two concave applicators, CCA and CCB manufactured by BEBIG and a complete mathematical model of the human eye were modeled using the MCNPX code. Results and Conclusion: For both eye models, namely water model and heterogeneous model, mean dose values simulated for the same eye regions are, in general, very similar, excepting for regions very distant from the applicator, where mean dose values are very low, uncertainties are higher and relative differences may reach 20.4%. For the tumor base and the eye structures closest to the applicator, such as sclera, choroid and retina, the maximum difference observed was 4%, presenting the heterogeneous model higher mean dose values. For the other eye regions, the higher doses were obtained when the homogeneous water eye model is taken into consideration. Mean dose distributions determined for the homogeneous water eye model are similar to those obtained for the

  16. High dose rate brachytherapy using custom made superficial mould applicators and Leipzig applicators for non melanoma localized skin cancer

    Energy Technology Data Exchange (ETDEWEB)

    Pellizzon, A. Cassio A.; Miziara, Daniela; Lima, Flavia Pedroso de; Miziara, Miguel

    2014-07-01

    Purpose: advances in technology and the commercial production of Leipzig applicators allowed High Dose Rate after-load brachytherapy (HDR-BT) to address a number of the challenges associated with the delivery of superficial radiation to treat localized non melanoma skin cancer (NMSK). We reviewed our uni-institutional experience on the treatment of NMSK with HDR-BT. Methods: data were collected retrospectively from patients attending the Radiation Oncology Department at AV Carvalho Insitute, Sao Paulo, Brazil. HDR-BT was done using the stepping source HDR 192Ir Microselectron (Nucletron BV). The planning target volume consisted of the macroscopic lesion plus a 5mm to 10mm margin.The depth of treatment was 0.5 cm in smaller (< 2.0 cm) tumors and 10 to 15 mm for lesions bigger than that. Results: Thirteen patients were treated with HDR-BT from June, 2007 to June 2013. The median age and follow up time were 72 (38-90) years old and 36 (range, 7-73) months, respectively. There a predominance of males (61.5%) and of patients referred for adjuvant treatment due positive surgical margins or because they have had only a excision biopsy without safety margins (61.5%). Six (46.2%) patients presented with squamous cell carcinoma and 7 (53.8%) patients presented with basal cell carcinoma. The median tumor size was 20 (range, 5-42) mm. Patients were treated with a median total dose of 40 Gy (range, 20 -60), given in 10 (range, 2-15) fractions, given daily or twice a week. All patients responded very well to treatment and only one patient has failed locally so far, after 38 months of the end of the irradiation. The crude and actuarial 3-year local control rates were 100% and 80%, respectively. Moist desquamation, grade 2 RTOG, was observed in 4 (30.8%) patients. Severe late complication, radiation-induced dyspigmentation, occurred in 2 patients and 1 of the patients also showed telangiectasia in the irradiated area. The cosmetic result was considered good in 84% (11/13) patients

  17. High dose rate brachytherapy using custom made superficial mould applicators and Leipzig applicators for non melanoma localized skin cancer

    International Nuclear Information System (INIS)

    Pellizzon, A. Cassio A.; Miziara, Daniela; Lima, Flavia Pedroso de; Miziara, Miguel

    2014-01-01

    Purpose: advances in technology and the commercial production of Leipzig applicators allowed High Dose Rate after-load brachytherapy (HDR-BT) to address a number of the challenges associated with the delivery of superficial radiation to treat localized non melanoma skin cancer (NMSK). We reviewed our uni-institutional experience on the treatment of NMSK with HDR-BT. Methods: data were collected retrospectively from patients attending the Radiation Oncology Department at AV Carvalho Insitute, Sao Paulo, Brazil. HDR-BT was done using the stepping source HDR 192Ir Microselectron (Nucletron BV). The planning target volume consisted of the macroscopic lesion plus a 5mm to 10mm margin.The depth of treatment was 0.5 cm in smaller (< 2.0 cm) tumors and 10 to 15 mm for lesions bigger than that. Results: Thirteen patients were treated with HDR-BT from June, 2007 to June 2013. The median age and follow up time were 72 (38-90) years old and 36 (range, 7-73) months, respectively. There a predominance of males (61.5%) and of patients referred for adjuvant treatment due positive surgical margins or because they have had only a excision biopsy without safety margins (61.5%). Six (46.2%) patients presented with squamous cell carcinoma and 7 (53.8%) patients presented with basal cell carcinoma. The median tumor size was 20 (range, 5-42) mm. Patients were treated with a median total dose of 40 Gy (range, 20 -60), given in 10 (range, 2-15) fractions, given daily or twice a week. All patients responded very well to treatment and only one patient has failed locally so far, after 38 months of the end of the irradiation. The crude and actuarial 3-year local control rates were 100% and 80%, respectively. Moist desquamation, grade 2 RTOG, was observed in 4 (30.8%) patients. Severe late complication, radiation-induced dyspigmentation, occurred in 2 patients and 1 of the patients also showed telangiectasia in the irradiated area. The cosmetic result was considered good in 84% (11/13) patients

  18. Topical application of β-radiation to reduce intimal hyperplasia after carotid artery balloon injury in rabbit A possible application for brachytherapy in vascular surgery

    International Nuclear Information System (INIS)

    Rosenthal, David; Stevens, Scott L.; Skillern, C.S.; Wellons, Eric D.; Robinson, Keith; Matsuura, John H.; Gannon, Brian J.

    2002-01-01

    Purpose: Endovascular brachytherapy for the prevention of intimal hyperplasia (IH) and restenosis after balloon/stent angioplasty has proven effective both in animal preparations and clinical trials. A variety of β-emitting isotopes and catheter-based devices have been developed for the delivery of low-dose radiation in clinical coronary and peripheral trials. No platform, however, has yet been developed for brachytherapy in concert with vascular surgical operations. The purpose of this study was to evaluate the vascular histopathologic response following balloon injury to rabbit carotid arteries with and without topically applied low-dose β-radiation. Methods: The β-emitting isotope strontium-90 (Sr-90) was conjugated onto the matrix of polypropylene (PLYP) mesh. Rabbit carotid arteries were balloon-injured with a no. 2 embolectomy catheter. Six carotid arteries were wrapped with nonradioactive PLYP mesh (controls) and Sr-90 (∼90 μCi) PLYP mesh in order to deliver low-dose radiation to the vessel wall from the external (adventitial) surface. Tissue was harvested at 6 weeks and processed for histologic examination. Results: There was consistent blockade of fibrocellular neointima formation with virtually no neointima present in all treated segments, compared to moderate neointima formation in controls. Medial thinning and smooth muscle cell (SMC) necrosis were also associated with topical brachytherapy. Conclusion: β-Radiation applied by an externally wrapped PLYP mesh labeled with Sr-90 markedly suppressed neointima formation in an animal vascular surgical injury model. Further studies, however, are necessary to determine a suitable isotope and dosage for clinical application

  19. Comparison between beta radiation dose distribution due to LDR and HDR ocular brachytherapy applicators using GATE Monte Carlo platform.

    Science.gov (United States)

    Mostafa, Laoues; Rachid, Khelifi; Ahmed, Sidi Moussa

    2016-08-01

    Eye applicators with 90Sr/90Y and 106Ru/106Rh beta-ray sources are generally used in brachytherapy for the treatment of eye diseases as uveal melanoma. Whenever, radiation is used in treatment, dosimetry is essential. However, knowledge of the exact dose distribution is a critical decision-making to the outcome of the treatment. The Monte Carlo technique provides a powerful tool for calculation of the dose and dose distributions which helps to predict and determine the doses from different shapes of various types of eye applicators more accurately. The aim of this work consisted in using the Monte Carlo GATE platform to calculate the 3D dose distribution on a mathematical model of the human eye according to international recommendations. Mathematical models were developed for four ophthalmic applicators, two HDR 90Sr applicators SIA.20 and SIA.6, and two LDR 106Ru applicators, a concave CCB model and a flat CCB model. In present work, considering a heterogeneous eye phantom and the chosen tumor, obtained results with the use of GATE for mean doses distributions in a phantom and according to international recommendations show a discrepancy with respect to those specified by the manufacturers. The QC of dosimetric parameters shows that contrarily to the other applicators, the SIA.20 applicator is consistent with recommendations. The GATE platform show that the SIA.20 applicator present better results, namely the dose delivered to critical structures were lower compared to those obtained for the other applicators, and the SIA.6 applicator, simulated with MCNPX generates higher lens doses than those generated by GATE. Copyright © 2016 Associazione Italiana di Fisica Medica. Published by Elsevier Ltd. All rights reserved.

  20. SU-E-J-207: Effect of Pulse Sequence Parameters On Geometric Distortions Induced by a Titanium Brachytherapy Applicator

    International Nuclear Information System (INIS)

    Shea, S; Diak, A; Surucu, M; Harkenrider, M; Yacoub, J; Roeske, J; Small, W

    2015-01-01

    Purpose: To investigate the effect of readout bandwidth and voxel size on the appearance of distortion artifacts caused by a titanium brachytherapy applicator. Methods: An acrylic phantom was constructed to rigidly hold a MR conditional, titanium Fletcher-Suit-Delclos-style applicator set (Varian Medical Systems) for imaging on CT (Philips Brilliance) and 1.5T MRI (Siemens Magnetom Aera). Several variants of MRI parameters were tried for 2D T2-weighted turbo spin echo imaging in comparison against the standard clinical protocol with the criteria to keep relative SNR loss less than 20% and imaging time as short as possible. Two 3D sequences were also used for comparison with similar parameters. The applicator tandem was segmented on axial CT images (0.4×0.4×1.5mm 3 resolution) and the CT images were registered to the 3D MR images in Eclipse (Varian). The applicator volume was then overlaid on all MRI sets in 3D-Slicer and distances were measured from the tandem tip to the MRI artifact edge in right/left/superior and anterior/posterior/superior directions from coronal and sagittal 2D acquisitions, respectively, or 3D data reformats. Artifact regions were also manually contoured in coronal/sagittal orientations for area measurements. Results: As would be expected, reductions in voxel size and increases in readout bandwidth reduced artifact size (average max artifact length decreased by 0.95 mm and average max area decrease by 0.27 cm 2 ). Interestingly, bandwidth increases yielded reductions in area (0.19 cm 2 ) and in distance measurements (1 mm) even with voxel increases, as compared to a standard protocol. This could be useful when high performance protocols are not feasible due to long imaging times. Conclusion: We have characterized artifacts caused by cervical brachytherapy applicator across multiple sequence parameters at 1.5T. Future work will focus on finalizing an optimal protocol that balances artifact reduction with imaging time and then testing this new

  1. Poster - Thur Eve - 03: LDR to HDR: RADPOS applications in brachytherapy.

    Science.gov (United States)

    Cherpak, A J; Cygler, J E; Kertzscher, G; E, C; Perry, G

    2012-07-01

    The RADPOS in vivo dosimetry system combines an electromagnetic positioning sensor and either one or five MOSFET dosimeters. The feasibility of using the system for quality control has been explored for a range of radiotherapy treatment techniques including most recently transperineal interstitial permanent prostate brachytherapy and high dose rate (HDR) treatments. Dose and position information was collected by a RADPOS array detector inside a Foley catheter within patients' urethra during permanent seed implantation. Ten patients were studied, and average displacement during implantation was Δr = (1.4-5.1) mm, with movements up to 9.7 mm due to the removal of the transrectal ultrasound probe. Maximum integral dose in the prostatic urethra ranged from 110-195 Gy, and it was found that the dose can change up to 63 cGy (62.0%) depending on whether the rectal probe is in place. For HDR, a RADPOS detector was first calibrated with an Ir-192 source. A treatment was then simulated using a total of 50 dwell positions in 5 catheters in an acrylic phantom. Dwell positions ranged from 1 to 10 cm away from the RADPOS detector and dose was measured for each source position. An average calibration coefficient of 0.74±0.11 cGy/mV was calculated for the detector and the average absolute difference between measured values and expected dose was 0.7±5.4 cGy (5±20%). The demonstrated accuracy of RADPOS dose measurements along with its ability to simultaneously measure displacement makes it a powerful tool for brachytherapy treatments, where high dose gradients can present unique in vivo dosimetry challenges. © 2012 American Association of Physicists in Medicine.

  2. Applications of the Italian protocol for the calibration of brachytherapy sources

    International Nuclear Information System (INIS)

    Piermattei, A.; Azario, L.

    1997-01-01

    The Associazione Italiana di Fisica Biomedica (AIFB; Italian Association of Biomedical Physics) has adopted the Italian protocol for the calibration of brachytherapy sources. The AIFB protocol allows measurements of the reference air kerma rate, dK/dt r , within 1.7% (1σ). To measure dK/dt r the AIFB protocol has identified a direct and an indirect procedure. The direct procedure is based on the use of spherical or cylindrical ionization chambers as local reference dosimeters positioned along the transverse bisector axis of the source. Once the source is specified by a dK/dt r value, this can be used to calibrate a field instrument, such as a well-type ionization chamber, for further source calibrations by means of an indirect procedure. This paper reports the results obtained by the Physics Laboratory of the Universita Cattolica del S Cuore (PL-UCSC), in terms of dK/dt r calibration of five types of source, 169 Yb, 192 Ir and 137 Cs. The role of the dK/dt r determination for a brachytherapy source has been underlined when a new source such as the 169 Yb seed model X1267 has been proposed for clinical use. The dK/dt r values for 137 Cs spherical sources differed by 5% from the vendor's mean value. The five types of source calibrated in terms of dK/dt r were used to obtain the calibration factor, N K r source , of an HDR-1000 well-type ionization chamber. (author)

  3. Patient-related factors determining geometry of intracavitary applicators and pelvic dose distribution during cervical cancer brachytherapy

    International Nuclear Information System (INIS)

    Senkus-Konefka, Elzbieta; Kobierska, Anna; Jassem, Jacek; Badzio, Andrezej

    1997-01-01

    Purpose: The aim of this study was to assess retrospectively the influence of the size of cervical cancer brachytherapy applicators (ovoids and uterine tandems) on pelvic dose distribution and to analyze the impact of various patient-and disease-related factors on applicators' geometry and on dose distribution in particular applications. Methods and Materials: The subject of this study were 356 cervical cancer patients treated with Selectron LDR as a part of their radical radiotherapy. Analyzed factors included patient age, weight, number of vaginal deliveries, and disease stage. Results: The use of larger vaginal applicators resulted in lower bladder and rectum doses and in higher point B doses (all p < 0.0001); longer uterine tandems produced lower rectum doses and higher point B doses (both p < 0.0001). Increasing patient age and disease stage resulted in a decreased frequency of use of large ovoids (both p < 0.0001) and of long tandems (age: p = 0.0069, stage: p = 0.004). As a result, higher doses to bladder (age: p < 0.0001, stage: p = 0.017) and rectum (age: p = 0.037, stage: p = 0.011) were observed. Increasing age also resulted in lower point B doses (p < 0.0001). Increasing patient weight correlated with less frequent use of long tandems (p = 0.0015) and with higher bladder doses (p = 0.04). Higher number of vaginal deliveries was related to the increase in the use of long tandems (p = 0.002); in patients who had had at least one vaginal delivery, point B doses were significantly higher (p = 0.0059). In multivariate analysis ovoid size and uterine tandem length were dependent on patient age (respectively: p < 0.001 and p = 0.001), disease stage (respectively: p = 0.003 and p = 0.008) and on the number of vaginal deliveries (respectively: p = 0.07 and p 0.008). Doses to critical organs and to points B were dependent on patient age (respectively: p < 0.001, p = 0.011, and p < 0.001) and on disease stage (respectively: p < 0.001, p = 0.004, and p = 0

  4. Value of Magnetic Resonance Imaging Without or With Applicator in Place for Target Definition in Cervix Cancer Brachytherapy

    Energy Technology Data Exchange (ETDEWEB)

    Pötter, Richard [Department of Radiotherapy, Comprehensive Cancer Center, Medical University of Vienna, Vienna (Austria); Christian Doppler Laboratory for Medical Radiation Research for Radiation Oncology, Medical University of Vienna, Vienna (Austria); Federico, Mario [Department of Radiotherapy, Comprehensive Cancer Center, Medical University of Vienna, Vienna (Austria); Department of Radiation Oncology, Gran Canaria University Hospital, Las Palmas de Gran Canaria (Spain); Sturdza, Alina [Department of Radiotherapy, Comprehensive Cancer Center, Medical University of Vienna, Vienna (Austria); Fotina, Irina [Department of Radiotherapy, Comprehensive Cancer Center, Medical University of Vienna, Vienna (Austria); Institute of Physics and Technology, Tomsk Polytechnic University, Tomsk Oblast (Russian Federation); Hegazy, Neamat [Department of Radiotherapy, Comprehensive Cancer Center, Medical University of Vienna, Vienna (Austria); Department of Clinical Oncology, Medical University of Alexandria, Alexandria (Egypt); Schmid, Maximilian; Kirisits, Christian [Department of Radiotherapy, Comprehensive Cancer Center, Medical University of Vienna, Vienna (Austria); Christian Doppler Laboratory for Medical Radiation Research for Radiation Oncology, Medical University of Vienna, Vienna (Austria); Nesvacil, Nicole, E-mail: nicole.nesvacil@meduniwien.ac.at [Department of Radiotherapy, Comprehensive Cancer Center, Medical University of Vienna, Vienna (Austria); Christian Doppler Laboratory for Medical Radiation Research for Radiation Oncology, Medical University of Vienna, Vienna (Austria)

    2016-03-01

    Purpose: To define, in the setting of cervical cancer, to what extent information from additional pretreatment magnetic resonance imaging (MRI) without the brachytherapy applicator improves conformity of CT-based high-risk clinical target volume (CTV{sub HR}) contours, compared with the MRI for various tumor stages (International Federation of Gynecology and Obstetrics [FIGO] stages I-IVA). Methods and Materials: The CTV{sub HR} was contoured in 39 patients with cervical cancer (FIGO stages I-IVA) (1) on CT images based on clinical information (CTV{sub HR}-CT{sub Clinical}) alone; and (2) using an additional MRI before brachytherapy, without the applicator (CTV{sub HR}-CT{sub pre-BT} {sub MRI}). The CT contours were compared with reference contours on MRI with the applicator in place (CTV{sub HR}-MRI{sub ref}). Width, height, thickness, volumes, and topography were analyzed. Results: The CT-MRI{sub ref} differences hardly varied in stage I tumors (n=8). In limited-volume stage IIB and IIIB tumors (n=19), CTV{sub HR}-CT{sub pre-BT} {sub MRI}–MRI{sub ref} volume differences (2.6 cm{sup 3} [IIB], 7.3 cm{sup 3} [IIIB]) were superior to CTV{sub HR}-CT{sub Clinical}–MRI{sub ref} (11.8 cm{sup 3} [IIB], 22.9 cm{sup 3} [IIIB]), owing to significant improvement of height and width (P<.05). In advanced disease (n=12), improved agreement with MR volume, width, and height was achieved for CTV{sub HR}-CT{sub pre-BT} {sub MRI}. In 5 of 12 cases, MRI{sub ref} contours were partly missed on CT. Conclusions: Pre-BT MRI helps to define CTV{sub HR} before BT implantation appropriately, if only CT images with the applicator in place are available for BT planning. Significant improvement is achievable in limited-volume stage IIB and IIIB tumors. In more advanced disease (extensive IIB to IVA), improvement of conformity is possible but may be associated with geographic misses. Limited impact on precision of CTV{sub HR}-CT is expected in stage IB tumors.

  5. Value of Magnetic Resonance Imaging Without or With Applicator in Place for Target Definition in Cervix Cancer Brachytherapy

    International Nuclear Information System (INIS)

    Pötter, Richard; Federico, Mario; Sturdza, Alina; Fotina, Irina; Hegazy, Neamat; Schmid, Maximilian; Kirisits, Christian; Nesvacil, Nicole

    2016-01-01

    Purpose: To define, in the setting of cervical cancer, to what extent information from additional pretreatment magnetic resonance imaging (MRI) without the brachytherapy applicator improves conformity of CT-based high-risk clinical target volume (CTV_H_R) contours, compared with the MRI for various tumor stages (International Federation of Gynecology and Obstetrics [FIGO] stages I-IVA). Methods and Materials: The CTV_H_R was contoured in 39 patients with cervical cancer (FIGO stages I-IVA) (1) on CT images based on clinical information (CTV_H_R-CT_C_l_i_n_i_c_a_l) alone; and (2) using an additional MRI before brachytherapy, without the applicator (CTV_H_R-CT_p_r_e_-_B_T _M_R_I). The CT contours were compared with reference contours on MRI with the applicator in place (CTV_H_R-MRI_r_e_f). Width, height, thickness, volumes, and topography were analyzed. Results: The CT-MRI_r_e_f differences hardly varied in stage I tumors (n=8). In limited-volume stage IIB and IIIB tumors (n=19), CTV_H_R-CT_p_r_e_-_B_T _M_R_I–MRI_r_e_f volume differences (2.6 cm"3 [IIB], 7.3 cm"3 [IIIB]) were superior to CTV_H_R-CT_C_l_i_n_i_c_a_l–MRI_r_e_f (11.8 cm"3 [IIB], 22.9 cm"3 [IIIB]), owing to significant improvement of height and width (P<.05). In advanced disease (n=12), improved agreement with MR volume, width, and height was achieved for CTV_H_R-CT_p_r_e_-_B_T _M_R_I. In 5 of 12 cases, MRI_r_e_f contours were partly missed on CT. Conclusions: Pre-BT MRI helps to define CTV_H_R before BT implantation appropriately, if only CT images with the applicator in place are available for BT planning. Significant improvement is achievable in limited-volume stage IIB and IIIB tumors. In more advanced disease (extensive IIB to IVA), improvement of conformity is possible but may be associated with geographic misses. Limited impact on precision of CTV_H_R-CT is expected in stage IB tumors.

  6. Accuracy of applicator tip reconstruction in MRI-guided interstitial 192Ir-high-dose-rate brachytherapy of liver tumors

    International Nuclear Information System (INIS)

    Wybranski, Christian; Eberhardt, Benjamin; Fischbach, Katharina; Fischbach, Frank; Walke, Mathias; Hass, Peter; Röhl, Friedrich-Wilhelm; Kosiek, Ortrud; Kaiser, Mandy; Pech, Maciej; Lüdemann, Lutz; Ricke, Jens

    2015-01-01

    Background and purpose: To evaluate the reconstruction accuracy of brachytherapy (BT) applicators tips in vitro and in vivo in MRI-guided 192 Ir-high-dose-rate (HDR)-BT of inoperable liver tumors. Materials and methods: Reconstruction accuracy of plastic BT applicators, visualized by nitinol inserts, was assessed in MRI phantom measurements and in MRI 192 Ir-HDR-BT treatment planning datasets of 45 patients employing CT co-registration and vector decomposition. Conspicuity, short-term dislocation, and reconstruction errors were assessed in the clinical data. The clinical effect of applicator reconstruction accuracy was determined in follow-up MRI data. Results: Applicator reconstruction accuracy was 1.6 ± 0.5 mm in the phantom measurements. In the clinical MRI datasets applicator conspicuity was rated good/optimal in ⩾72% of cases. 16/129 applicators showed not time dependent deviation in between MRI/CT acquisition (p > 0.1). Reconstruction accuracy was 5.5 ± 2.8 mm, and the average image co-registration error was 3.1 ± 0.9 mm. Vector decomposition revealed no preferred direction of reconstruction errors. In the follow-up data deviation of planned dose distribution and irradiation effect was 6.9 ± 3.3 mm matching the mean co-registration error (6.5 ± 2.5 mm; p > 0.1). Conclusion: Applicator reconstruction accuracy in vitro conforms to AAPM TG 56 standard. Nitinol-inserts are feasible for applicator visualization and yield good conspicuity in MRI treatment planning data. No preferred direction of reconstruction errors were found in vivo

  7. 3D shape measurement for moving scenes using an interlaced scanning colour camera

    International Nuclear Information System (INIS)

    Cao, Senpeng; Cao, Yiping; Lu, Mingteng; Zhang, Qican

    2014-01-01

    A Fourier transform deinterlacing algorithm (FTDA) is proposed to eliminate the blurring and dislocation of the fringe patterns on a moving object captured by an interlaced scanning colour camera in phase measuring profilometry (PMP). Every frame greyscale fringe from three colour channels of every colour fringe is divided into even and odd field fringes respectively, each of which is respectively processed by FTDA. All of the six frames deinterlaced fringes from one colour fringe form two sets of three-step phase-shifted greyscale fringes, with which two 3D shapes corresponding to two different moments are reconstructed by PMP within a frame period. The deinterlaced fringe is identical with the exact frame fringe at the same moment theoretically. The simulation and experiments show its feasibility and validity. The method doubles the time resolution, maintains the precision of the traditional phase measurement profilometry, and has potential applications in the moving and online object’s 3D shape measurements. (paper)

  8. Application of Multiobjective Genetic Algorithms in Anatomy Based Dose Optimization in Brachytherapy and its Comparation with Deterministic Algorithms

    National Research Council Canada - National Science Library

    Milickovic, Natasa

    2001-01-01

    In High Dose Rate (HDR) brachytherapy the conventional dose optimization algorithms consider the multiple objectives in the form of an aggregate function which combines individual objectives into a single utility value...

  9. 3D shape decomposition and comparison for gallbladder modeling

    Science.gov (United States)

    Huang, Weimin; Zhou, Jiayin; Liu, Jiang; Zhang, Jing; Yang, Tao; Su, Yi; Law, Gim Han; Chui, Chee Kong; Chang, Stephen

    2011-03-01

    This paper presents an approach to gallbladder shape comparison by using 3D shape modeling and decomposition. The gallbladder models can be used for shape anomaly analysis and model comparison and selection in image guided robotic surgical training, especially for laparoscopic cholecystectomy simulation. The 3D shape of a gallbladder is first represented as a surface model, reconstructed from the contours segmented in CT data by a scheme of propagation based voxel learning and classification. To better extract the shape feature, the surface mesh is further down-sampled by a decimation filter and smoothed by a Taubin algorithm, followed by applying an advancing front algorithm to further enhance the regularity of the mesh. Multi-scale curvatures are then computed on the regularized mesh for the robust saliency landmark localization on the surface. The shape decomposition is proposed based on the saliency landmarks and the concavity, measured by the distance from the surface point to the convex hull. With a given tolerance the 3D shape can be decomposed and represented as 3D ellipsoids, which reveal the shape topology and anomaly of a gallbladder. The features based on the decomposed shape model are proposed for gallbladder shape comparison, which can be used for new model selection. We have collected 19 sets of abdominal CT scan data with gallbladders, some shown in normal shape and some in abnormal shapes. The experiments have shown that the decomposed shapes reveal important topology features.

  10. 3D shape recovery from image focus using Gabor features

    Science.gov (United States)

    Mahmood, Fahad; Mahmood, Jawad; Zeb, Ayesha; Iqbal, Javaid

    2018-04-01

    Recovering an accurate and precise depth map from a set of acquired 2-D image dataset of the target object each having different focus information is an ultimate goal of 3-D shape recovery. Focus measure algorithm plays an important role in this architecture as it converts the corresponding color value information into focus information which will be then utilized for recovering depth map. This article introduces Gabor features as focus measure approach for recovering depth map from a set of 2-D images. Frequency and orientation representation of Gabor filter features is similar to human visual system and normally applied for texture representation. Due to its little computational complexity, sharp focus measure curve, robust to random noise sources and accuracy, it is considered as superior alternative to most of recently proposed 3-D shape recovery approaches. This algorithm is deeply investigated on real image sequences and synthetic image dataset. The efficiency of the proposed scheme is also compared with the state of art 3-D shape recovery approaches. Finally, by means of two global statistical measures, root mean square error and correlation, we claim that this approach, in spite of simplicity, generates accurate results.

  11. Fast dose kernel interpolation using Fourier transform with application to permanent prostate brachytherapy dosimetry.

    Science.gov (United States)

    Liu, Derek; Sloboda, Ron S

    2014-05-01

    Boyer and Mok proposed a fast calculation method employing the Fourier transform (FT), for which calculation time is independent of the number of seeds but seed placement is restricted to calculation grid points. Here an interpolation method is described enabling unrestricted seed placement while preserving the computational efficiency of the original method. The Iodine-125 seed dose kernel was sampled and selected values were modified to optimize interpolation accuracy for clinically relevant doses. For each seed, the kernel was shifted to the nearest grid point via convolution with a unit impulse, implemented in the Fourier domain. The remaining fractional shift was performed using a piecewise third-order Lagrange filter. Implementation of the interpolation method greatly improved FT-based dose calculation accuracy. The dose distribution was accurate to within 2% beyond 3 mm from each seed. Isodose contours were indistinguishable from explicit TG-43 calculation. Dose-volume metric errors were negligible. Computation time for the FT interpolation method was essentially the same as Boyer's method. A FT interpolation method for permanent prostate brachytherapy TG-43 dose calculation was developed which expands upon Boyer's original method and enables unrestricted seed placement. The proposed method substantially improves the clinically relevant dose accuracy with negligible additional computation cost, preserving the efficiency of the original method.

  12. High density low-q discharges with D-shaped plasmas in Doublet III

    International Nuclear Information System (INIS)

    Nagami, Masayuki; Yoshida, Hidetoshi; Shinya, Kichiro; Yokomizo, Hideaki; Shimada, Michiya; Ioki, Kimihiro; Izumi, Shigeru; Kitsunezaki, Masao; Jahns, G.

    1981-07-01

    The maximum plasma current in Doublet III is found to be limited by disruptions when the limiter safety factor is approximately 2. However, due to the strong toroidal and shaping field effect on rotational transform at the outer plasma edge associated with a D-shape formation having a vertical elongation of 1.5, the safety factor q sub(a) * estimated from simple geometric considerations for D-shaped plasmas corresponds to values as low as 1.5. These discharges operate stably with considerably higher plasma current than most reactor design studies assume. These low-q discharges show excellent plasma performance: very flat spatial electron temperature progiles, high density operation with anti n sub(e)R/B sub(T) up to 7.8, and good energy confinement producing a volume average β of up to 1% with ohmic heating only. This operational regime appears to be applicable to future high β tokamaks with D-shaped cross section. (author)

  13. SU-F-T-65: AutomaticTreatment Planning for High-Dose Rate (HDR) Brachytherapy with a VaginalCylinder Applicator

    International Nuclear Information System (INIS)

    Zhou, Y; Tan, J; Jiang, S; Albuquerque, K; Jia, X

    2016-01-01

    Purpose: High dose rate (HDR) brachytherapy treatment planning is conventionally performed in a manual fashion. Yet it is highly desirable to perform computerized automated planning to improve treatment planning efficiency, eliminate human errors, and reduce plan quality variation. The goal of this research is to develop an automatic treatment planning tool for HDR brachytherapy with a cylinder applicator for vaginal cancer. Methods: After inserting the cylinder applicator into the patient, a CT scan was acquired and was loaded to an in-house developed treatment planning software. The cylinder applicator was automatically segmented using image-processing techniques. CTV was generated based on user-specified treatment depth and length. Locations of relevant points (apex point, prescription point, and vaginal surface point), central applicator channel coordinates, and dwell positions were determined according to their geometric relations with the applicator. Dwell time was computed through an inverse optimization process. The planning information was written into DICOM-RT plan and structure files to transfer the automatically generated plan to a commercial treatment planning system for plan verification and delivery. Results: We have tested the system retrospectively in nine patients treated with vaginal cylinder applicator. These cases were selected with different treatment prescriptions, lengths, depths, and cylinder diameters to represent a large patient population. Our system was able to generate treatment plans for these cases with clinically acceptable quality. Computation time varied from 3–6 min. Conclusion: We have developed a system to perform automated treatment planning for HDR brachytherapy with a cylinder applicator. Such a novel system has greatly improved treatment planning efficiency and reduced plan quality variation. It also served as a testbed to demonstrate the feasibility of automatic HDR treatment planning for more complicated cases.

  14. SU-F-T-65: AutomaticTreatment Planning for High-Dose Rate (HDR) Brachytherapy with a VaginalCylinder Applicator

    Energy Technology Data Exchange (ETDEWEB)

    Zhou, Y; Tan, J; Jiang, S; Albuquerque, K; Jia, X [UT Southwestern Medical Center, Dallas, TX (United States)

    2016-06-15

    Purpose: High dose rate (HDR) brachytherapy treatment planning is conventionally performed in a manual fashion. Yet it is highly desirable to perform computerized automated planning to improve treatment planning efficiency, eliminate human errors, and reduce plan quality variation. The goal of this research is to develop an automatic treatment planning tool for HDR brachytherapy with a cylinder applicator for vaginal cancer. Methods: After inserting the cylinder applicator into the patient, a CT scan was acquired and was loaded to an in-house developed treatment planning software. The cylinder applicator was automatically segmented using image-processing techniques. CTV was generated based on user-specified treatment depth and length. Locations of relevant points (apex point, prescription point, and vaginal surface point), central applicator channel coordinates, and dwell positions were determined according to their geometric relations with the applicator. Dwell time was computed through an inverse optimization process. The planning information was written into DICOM-RT plan and structure files to transfer the automatically generated plan to a commercial treatment planning system for plan verification and delivery. Results: We have tested the system retrospectively in nine patients treated with vaginal cylinder applicator. These cases were selected with different treatment prescriptions, lengths, depths, and cylinder diameters to represent a large patient population. Our system was able to generate treatment plans for these cases with clinically acceptable quality. Computation time varied from 3–6 min. Conclusion: We have developed a system to perform automated treatment planning for HDR brachytherapy with a cylinder applicator. Such a novel system has greatly improved treatment planning efficiency and reduced plan quality variation. It also served as a testbed to demonstrate the feasibility of automatic HDR treatment planning for more complicated cases.

  15. Determining the distribution of the absorbed dose for a body exposed to Cs-137 using the Monte Carlo method and application in a brachytherapy treatment planning

    International Nuclear Information System (INIS)

    Randriantsizafy, R.D.

    2014-01-01

    Brachytherapy is a means of precise and effective cancer treatment. This is due to the nearby sources of ionizing radiation. The precision and efficiency requires a good dosimetry and a good knowledge of the dose distribution in the patient. The aim is to give the right dose of ionizing radiation to destroy the tumor while reducing the dose to sensitive organs such as the bladder , liver, .... The Monte Carlo is a recognized model method for the distribution of radiation in the material. It is used in this work to determine the doses to organs during treatment planning for Cesium -137 brachytherapy. The programming language used is Python . Library outcome of this work is used in a web application BrachyPy, we designed to replace the manual processing in the Cs-137 brachytherapy planning. Model validation is done by comparing the isodose curves of the model with the isodose curves abacus NUCLETRON and the last report of the American Association of Medical Physics (AAPM) on the amendment to the algorithm TG43. [fr

  16. Development of a reference system and a methodology for the calibration of ophthalmic applicators utilized in brachytherapy

    International Nuclear Information System (INIS)

    Oliveira, Mercia Liane de

    2005-01-01

    90 Sr+ 90 Y beta radiation sources are widely utilized in brachytherapy, in the treatment of superficial lesions of eyes and skin. According to international recommendations, these applicators should be specified in terms of the absorbed dose rate to water at the reference point (1 mm from the source surface, along its axis of symmetry). Two mini-extrapolation chambers were developed with adequate geometrical characteristics for the dosimetry of plane and concave 90 Sr+ 90 Y sources. These chambers have 3.0 cm of outer diameter and 11.3 cm of length. Aluminized polyester foils are used as entrance windows, and the collecting electrodes were made of graphited polymethylmethacrylate. The mini-chambers were tested in 90 Sr+ 90 Y radiation beams from a beta check source and plane and concave ophthalmic applicators. All results obtained show the usefulness of these chambers as reference primary standards for the calibration of 90 Sr+ 90 Y applicators. The previous calibration of the mini-chambers in relation to a standard ionization chamber or to a standard beta source is unnecessary. The minichamber with plane window showed utility for low energy X-rays too. In order to establish an alternative method for the calibration of beta radiation sources, different thermoluminescent materials were tested: LiF, CaF 2 :Mn, CaF 2 :Dy and CaS0 4 :Dy. For their characterization, the response reproducibility, calibration curves, TL response as a function of the source-detector distance, transmission factors and the linearity of the sample response were determined. The calibration procedures of ophthalmic applicators were established utilizing the ionometric technique and thermoluminescence dosimetry. (author)

  17. Monte Carlo study of LDR seed dosimetry with an application in a clinical brachytherapy breast implant.

    Science.gov (United States)

    Furstoss, C; Reniers, B; Bertrand, M J; Poon, E; Carrier, J-F; Keller, B M; Pignol, J P; Beaulieu, L; Verhaegen, F

    2009-05-01

    A Monte Carlo (MC) study was carried out to evaluate the effects of the interseed attenuation and the tissue composition for two models of 125I low dose rate (LDR) brachytherapy seeds (Medi-Physics 6711, IBt InterSource) in a permanent breast implant. The effect of the tissue composition was investigated because the breast localization presents heterogeneities such as glandular and adipose tissue surrounded by air, lungs, and ribs. The absolute MC dose calculations were benchmarked by comparison to the absolute dose obtained from experimental results. Before modeling a clinical case of an implant in heterogeneous breast, the effects of the tissue composition and the interseed attenuation were studied in homogeneous phantoms. To investigate the tissue composition effect, the dose along the transverse axis of the two seed models were calculated and compared in different materials. For each seed model, three seeds sharing the same transverse axis were simulated to evaluate the interseed effect in water as a function of the distance from the seed. A clinical study of a permanent breast 125I implant for a single patient was carried out using four dose calculation techniques: (1) A TG-43 based calculation, (2) a full MC simulation with realistic tissues and seed models, (3) a MC simulation in water and modeled seeds, and (4) a MC simulation without modeling the seed geometry but with realistic tissues. In the latter, a phase space file corresponding to the particles emitted from the external surface of the seed is used at each seed location. The results were compared by calculating the relevant clinical metrics V85, V100, and V200 for this kind of treatment in the target. D90 and D50 were also determined to evaluate the differences in dose and compare the results to the studies published for permanent prostate seed implants in literature. The experimental results are in agreement with the MC absolute doses (within 5% for EBT Gafchromic film and within 7% for TLD-100

  18. 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.

  19. Innovation in gynaecological brachytherapy: new technologies, pulse dose-rate brachytherapy, image, definition of new volumes of interest and their impact on dosimetry: application in a clinical research programme 'S.T.I.C.'

    International Nuclear Information System (INIS)

    Haie-Meder, C.; Peiffert, D.

    2006-01-01

    Brachytherapy plays a fundamental role in the therapeutic approach of patients with stage I-IV cervical carcinoma. Technical modalities have evolved during the last decades: stepping source technology, imaging modalities development, specially IMN, treatment planning system integrating 3D images. Images from CT-Scan and MRI have contributed to a better knowledge of tumoral extension and critical organs. CT and/or MRI compatible applicators allow a sectional image based approach with a better definition of tumour volume compared to traditional approaches. The introduction of 3D image based approach for GTV and CTV requires new definitions and a common language. In 2000, a working group within GEC-ESTRO was created to support 3D image based 3D treatment planning approach in cervix cancer BT. The task was to determine a common terminology enabling various groups to use a common language. Recommendations were described and proposed based on clinical experience and dosimetric concepts of different institutions. Two CTVs were described en relation to the risk for recurrence: high-risk CTV and intermediate risk CTV. In order to better define the role of such definitions and their potential impact on the complication incidence in patients with cervical cancer, a special French programme was developed. The aim of this programme is to study the incidence of the severe 2-year complication rate in two comparable patient populations: one population is treated using PDR brachytherapy with CT-Scan or MRI with the applicators in place allowing a 3D dosimetry with optimization, the second population is treated using standard X-rays radiographs, without any delineation of the target nor optimisation. Each population arm includes 425 patients. A medico-economic assessment is performed, allowing a real cost of the most sophisticated approach compared to a historical dosimetric system. (author)

  20. Uncertainties in Assesment of the Vaginal Dose for Intracavitary Brachytherapy of Cervical Cancer using a Tandem-ring Applicator

    International Nuclear Information System (INIS)

    Berger, Daniel; Dimopoulos, Johannes; Georg, Petra; Georg, Dietmar; Poetter, Richard; Kirisits, Christian

    2007-01-01

    Purpose: The vagina has not been widely recognized as organ at risk in brachytherapy for cervical cancer. No widely accepted dose parameters are available. This study analyzes the uncertainties in dose reporting for the vaginal wall using tandem-ring applicators. Methods and Materials: Organ wall contours were delineated on axial magnetic resonance (MR) slices to perform dose-volume histogram (DVH) analysis. Different DVH parameters were used in a feasibility study based on 40 magnetic resonance imaging (MRI)-based treatment plans of different cervical cancer patients. Dose to the most irradiated, 0.1 cm 3 , 1 cm 3 , 2 cm 3 , and at defined points on the ring surface and at 5-mm tissue depth were reported. Treatment-planning systems allow different methods of dose point definition. Film dosimetry was used to verify the maximum dose at the surface of the ring applicator in an experimental setup. Results: Dose reporting for the vagina is extremely sensitive to geometrical uncertainties with variations of 25% for 1 mm shifts. Accurate delineation of the vaginal wall is limited by the finite pixel size of MRI and available treatment-planning systems. No significant correlation was found between dose-point and dose-volume parameters. The DVH parameters were often related to noncontiguous volumes and were not able to detect very different situations of spatial dose distributions inside the vaginal wall. Deviations between measured and calculated doses were up to 21%. Conclusions: Reporting either point dose values or DVH parameters for the vaginal wall is based on high inaccuracies because of contouring and geometric positioning. Therefore, the use of prospective dose constraints for individual treatment plans is not to be recommended at present. However, for large patient groups treated within one protocol correlation with vaginal morbidity can be evaluated

  1. Use of a Flexible Inflatable Multi-Channel Applicator for Vaginal Brachytherapy in the Management of Gynecologic Cancer

    Directory of Open Access Journals (Sweden)

    Samuel M Shin

    2015-09-01

    Full Text Available Introduction: Evaluate use of novel multi-channel applicator (MC CapriTM to improve vaginal disease coverage achievable by single-channel applicator (SC and comparable to Syed plan simulation. Material and Methods: 28 plans were evaluated from 4 patients with primary or recurrent gynecologic cancer in the vagina. Each received whole pelvis radiation, followed by 3 weekly treatments using HDR brachytherapy with a 13-channel MC. Upper vagina was treated to 5 mm depth to 1500 cGy/3 fractions with a simultaneous integrated boost totaling 2100 cGy/3 fractions to tumor. Modeling of SC and Syed plans was performed using MC scans for each patient. Dosimetry for MC and SC plans was evaluated for PTV700 cGy coverage, maximum dose to 2cm3 to bladder, rectum as well as mucosal surface points. Dosimetry for Syed plans was calculated for PTV700 cGy coverage. Patients were followed for treatment response and toxicity.Results: Dosimetric analysis between MC and SC plans demonstrated increased tumor coverage (PTV700 cGy, with decreased rectal, bladder, and contralateral vaginal mucosa dose in favor of MC. These differences were significant (p<0.05. Comparison of MC and Syed plans demonstrated increased tumor coverage in favor of Syed plans which were not significant (p=0.71. Patients treated with MC had no cancer recurrence or ≥ grade 3 toxicity.Conclusion: Use of MC was efficacious and safe, providing superior coverage of tumor volumes ≤1cm depth compared to SC and comparable to Syed implant. MC avoids excess dose to surrounding organs compared to SC, and potentially less morbidity than Syed implants. For tumors extending ≤1cm depth, use of MC represents an alternative to an interstitial implant.

  2. Aesthetic preference recognition of 3D shapes using EEG.

    Science.gov (United States)

    Chew, Lin Hou; Teo, Jason; Mountstephens, James

    2016-04-01

    Recognition and identification of aesthetic preference is indispensable in industrial design. Humans tend to pursue products with aesthetic values and make buying decisions based on their aesthetic preferences. The existence of neuromarketing is to understand consumer responses toward marketing stimuli by using imaging techniques and recognition of physiological parameters. Numerous studies have been done to understand the relationship between human, art and aesthetics. In this paper, we present a novel preference-based measurement of user aesthetics using electroencephalogram (EEG) signals for virtual 3D shapes with motion. The 3D shapes are designed to appear like bracelets, which is generated by using the Gielis superformula. EEG signals were collected by using a medical grade device, the B-Alert X10 from advance brain monitoring, with a sampling frequency of 256 Hz and resolution of 16 bits. The signals obtained when viewing 3D bracelet shapes were decomposed into alpha, beta, theta, gamma and delta rhythm by using time-frequency analysis, then classified into two classes, namely like and dislike by using support vector machines and K-nearest neighbors (KNN) classifiers respectively. Classification accuracy of up to 80 % was obtained by using KNN with the alpha, theta and delta rhythms as the features extracted from frontal channels, Fz, F3 and F4 to classify two classes, like and dislike.

  3. Exploration of continuous variability in collections of 3D shapes

    KAUST Repository

    Ovsjanikov, Maks; Li, Wilmot; Guibas, Leonidas J.; Mitra, Niloy J.

    2011-01-01

    As large public repositories of 3D shapes continue to grow, the amount of shape variability in such collections also increases, both in terms of the number of different classes of shapes, as well as the geometric variability of shapes within each class. While this gives users more choice for shape selection, it can be difficult to explore large collections and understand the range of variations amongst the shapes. Exploration is particularly challenging for public shape repositories, which are often only loosely tagged and contain neither point-based nor part-based correspondences. In this paper, we present a method for discovering and exploring continuous variability in a collection of 3D shapes without correspondences. Our method is based on a novel navigation interface that allows users to explore a collection of related shapes by deforming a base template shape through a set of intuitive deformation controls. We also help the user to select the most meaningful deformations using a novel technique for learning shape variability in terms of deformations of the template. Our technique assumes that the set of shapes lies near a low-dimensional manifold in a certain descriptor space, which allows us to avoid establishing correspondences between shapes, while being rotation and scaling invariant. We present results on several shape collections taken directly from public repositories. © 2011 ACM.

  4. Exploration of continuous variability in collections of 3D shapes

    KAUST Repository

    Ovsjanikov, Maks

    2011-07-01

    As large public repositories of 3D shapes continue to grow, the amount of shape variability in such collections also increases, both in terms of the number of different classes of shapes, as well as the geometric variability of shapes within each class. While this gives users more choice for shape selection, it can be difficult to explore large collections and understand the range of variations amongst the shapes. Exploration is particularly challenging for public shape repositories, which are often only loosely tagged and contain neither point-based nor part-based correspondences. In this paper, we present a method for discovering and exploring continuous variability in a collection of 3D shapes without correspondences. Our method is based on a novel navigation interface that allows users to explore a collection of related shapes by deforming a base template shape through a set of intuitive deformation controls. We also help the user to select the most meaningful deformations using a novel technique for learning shape variability in terms of deformations of the template. Our technique assumes that the set of shapes lies near a low-dimensional manifold in a certain descriptor space, which allows us to avoid establishing correspondences between shapes, while being rotation and scaling invariant. We present results on several shape collections taken directly from public repositories. © 2011 ACM.

  5. Quasi-D-shaped optical fiber plasmonic refractive index sensor

    Science.gov (United States)

    An, Guowen; Li, Shuguang; Wang, Haiyang; Zhang, Xuenan; Yan, Xin

    2018-03-01

    A quasi-D-shaped photonic crystal fiber plasmonic sensor with a rectangular lattice is proposed by using Au as a plasmonic layer and graphene to enhance the sensing performance. By moving the core to the edge of the fiber, a shorter polishing depth is achieved, which makes the fiber proposed have a greater mechanical strength than other common D-shaped fibers. Benefiting from the natural advantage of the rectangular lattice, the dual sensing channels make the proposed sensor show a maximum wavelength interrogation sensitivity of 3877 nm/RIU with the dynamic refractive index range from 1.33 to 1.42 and a maximum amplitude sensitivity of 1236 RIU-1 with the analyte RI = 1.41 in the visible region. The corresponding resolutions are 2.58 × 10-5 and 8.1 × 10-6 with the methods of the wavelength interrogation method and amplitude- or phase-based method. These advantages make the proposed sensor a competitive candidate for biosensing in the field of refractive index detection, such as water quality analysis, clinical medicine detection, and pharmaceutical testing.

  6. SU-E-J-215: Towards MR-Only Image Guided Identification of Calcifications and Brachytherapy Seeds: Application to Prostate and Breast LDR Implant Dosimetry

    Energy Technology Data Exchange (ETDEWEB)

    Elzibak, A; Fatemi-Ardekani, A; Soliman, A; Mashouf, S; Safigholi, H; Ravi, A; Morton, G; Song, WY [Sunnybrook Health Sciences Centre, University of Toronto, Toronto, Ontario (Canada); Han, D [Sunnybrook Health Sciences Centre, University of Toronto, Toronto, Ontario (Canada); University of California, San Diego, La Jolla, CA (United States)

    2015-06-15

    Purpose: To identify and analyze the appearance of calcifications and brachytherapy seeds on magnitude and phase MRI images and to investigate whether they can be distinguished from each other on corrected phase images for application to prostate and breast low dose rate (LDR) implant dosimetry. Methods: An agar-based gel phantom containing two LDR brachytherapy seeds (Advantage Pd-103, IsoAid, 0.8mm diameter, 4.5mm length) and two spherical calcifications (large: 7mm diameter and small: 4mm diameter) was constructed and imaged on a 3T Philips MR scanner using a 16-channel head coil and a susceptibility weighted imaging (SWI) sequence (2mm slices, 320mm FOV, TR/ TE= 26.5/5.3ms, 15 degree flip angle). The phase images were unwrapped and corrected using a 32×32, 2D Hanning high pass filter to remove background phase noise. Appearance of the seeds and calcifications was assessed visually and quantitatively using Osirix (http://www.osirix-viewer.com/). Results: As expected, calcifications and brachytherapy seeds appeared dark (hypointense) relative to the surrounding gel on the magnitude MRI images. The diameter of each seed without the surrounding artifact was measured to be 0.1 cm on the magnitude image, while diameters of 0.79 and 0.37 cm were measured for the larger and smaller calcifications, respectively. On the corrected phase images, the brachytherapy seeds and the calcifications appeared bright (hyperintense). The diameter of the seeds was larger on the phase images (0.17 cm) likely due to the dipole effect. Conclusion: MRI has the best soft tissue contrast for accurate organ delineation leading to most accurate implant dosimetry. This work demonstrated that phase images can potentially be useful in identifying brachytherapy seeds and calcifications in the prostate and breast due to their bright appearance, which helps in their visualization and quantification for accurate dosimetry using MR-only. Future work includes optimizing phase filters to best identify

  7. Dosimetric properties of a novel brachytherapy balloon applicator for the treatment of malignant brain-tumor resection-cavity margins

    International Nuclear Information System (INIS)

    Dempsey, James F.; Williams, Jeffery A.; Stubbs, James B.; Patrick, Timothy J.; Williamson, Jeffrey F.

    1998-01-01

    Purpose: This paper characterizes the dosimetric properties of a novel balloon brachytherapy applicator for the treatment of the tissue surrounding the resection cavity of a malignant brain tumor. Methods and Materials: The applicator consists of an inflatable silicone balloon reservoir attached to a positionable catheter that is intraoperatively implanted into the resection cavity and postoperatively filled with a liquid radionuclide solution. A simple dosimetric model, valid in homogeneous media and based on results from Monte Carlo photon-transport simulations, was used to determine the dosimetric characteristics of spherical geometry balloons filled with photon-emitting radionuclide solutions. Fractional depth-dose (FDD) profiles, along with activity densities, and total activities needed to achieve specified dose rates were studied as a function of photon energy and source-containment geometry. Dose-volume histograms (DVHs) were calculated to compare idealized balloon-applicator treatments to conventional 125 I seed volume implants. Results: For achievable activity densities and total activities, classical low dose rate (LDR) treatments of residual disease at distances of up to 1 cm from the resection cavity wall are possible with balloon applicators having radii between 0.5 cm and 2.5 cm. The dose penetration of these applicators increases approximately linearly with balloon radius. The FDD profile can be made significantly more or less penetrating by combining selection of radionuclide with source-geometry manipulation. Comparisons with 125 I seed-implant DVHs show that the applicator can provide a more conformal therapy with no target tissue underdosing, less target tissue overdosing, and no healthy tissue ''hot spots;'' however, more healthy tissue volume receives a dose of the prescribed dosage or less. Conclusions: This device, when filled with 125 I solution, is suitable for classical LDR treatments and may be preferable to 125 I interstitial

  8. SU-F-E-13: Design and Fabrication of Gynacological Brachytherapy Shielding & Non Shielding Applicators Using Indigenously Developed 3D Printing Machine

    Energy Technology Data Exchange (ETDEWEB)

    Shanmugam, S

    2016-06-15

    Purpose: In this innovative work we have developed Gynecological Brachytherapy shielding & Non Shielding Applicators and compared with the commercially available applicators by using the indigenously developed 3D Printing machine. Methods: We have successfully indigenously developed the 3D printing machine. Which contain the 3 dimensional motion platform, Heater unit, base plate, ect… To fabricate the Gynecological Brachytherapy shielding & non shielding applicators the 3D design were developed in the computer as virtual design. This virtual design is made in a CAD computer file using a 3D modeling program. Separate programme for the shielding & non shielding applicators. We have also provided the extra catheter insert provision in the applicator for the multiple catheter. The DICOM file of the applicator were then converted to stereo Lithography file for the 3D printer. The shielding & Non Shielding Applicators were printed on a indigenously developed 3D printer material. The same dimensions were used to develop the applicators in the acrylic material also for the comparative study. A CT scan was performed to establish an infill-density calibration curve as well as characterize the quality of the print such as uniformity and the infill pattern. To commission the process, basic CT and dose properties of the printing materials were measured in photon beams and compared against water and soft tissue. Applicator were then scanned to confirm the placement of multiple catheter position. Finally dose distributions with rescanned CTs were compared with those computer-generated applicators. Results: The doses measured from the ion Chamber and X-Omat film test were within 2%. The shielded applicator reduce the rectal dose comparatively with the non shielded applicator. Conclusion: As of submission 3 unique cylinders have been designed, printed, and tested dosimetrically. A standardizable workflow for commissioning custom 3D printed applicators was codified and will be

  9. SU-F-E-13: Design and Fabrication of Gynacological Brachytherapy Shielding & Non Shielding Applicators Using Indigenously Developed 3D Printing Machine

    International Nuclear Information System (INIS)

    Shanmugam, S

    2016-01-01

    Purpose: In this innovative work we have developed Gynecological Brachytherapy shielding & Non Shielding Applicators and compared with the commercially available applicators by using the indigenously developed 3D Printing machine. Methods: We have successfully indigenously developed the 3D printing machine. Which contain the 3 dimensional motion platform, Heater unit, base plate, ect… To fabricate the Gynecological Brachytherapy shielding & non shielding applicators the 3D design were developed in the computer as virtual design. This virtual design is made in a CAD computer file using a 3D modeling program. Separate programme for the shielding & non shielding applicators. We have also provided the extra catheter insert provision in the applicator for the multiple catheter. The DICOM file of the applicator were then converted to stereo Lithography file for the 3D printer. The shielding & Non Shielding Applicators were printed on a indigenously developed 3D printer material. The same dimensions were used to develop the applicators in the acrylic material also for the comparative study. A CT scan was performed to establish an infill-density calibration curve as well as characterize the quality of the print such as uniformity and the infill pattern. To commission the process, basic CT and dose properties of the printing materials were measured in photon beams and compared against water and soft tissue. Applicator were then scanned to confirm the placement of multiple catheter position. Finally dose distributions with rescanned CTs were compared with those computer-generated applicators. Results: The doses measured from the ion Chamber and X-Omat film test were within 2%. The shielded applicator reduce the rectal dose comparatively with the non shielded applicator. Conclusion: As of submission 3 unique cylinders have been designed, printed, and tested dosimetrically. A standardizable workflow for commissioning custom 3D printed applicators was codified and will be

  10. Reproducibility and interoperator reliability of obtaining images and measurements of the cervix and uterus with brachytherapy treatment applicators in situ using transabdominal ultrasound.

    Science.gov (United States)

    van Dyk, Sylvia; Garth, Margaret; Oates, Amanda; Kondalsamy-Chennakesavan, Srinivas; Schneider, Michal; Bernshaw, David; Narayan, Kailash

    2016-01-01

    To validate interoperator reliability of brachytherapy radiation therapists (RTs) in obtaining an ultrasound image and measuring the cervix and uterine dimensions using transabdominal ultrasound. Patients who underwent MRI with applicators in situ after the first insertion were included in the study. Imaging was performed by three RTs (RT1, RT2, and RT3) with varying degrees of ultrasound experience. All RTs were required to obtain a longitudinal planning image depicting the applicator in the uterine canal and measure the cervix and uterus. The MRI scan, taken 1 hour after the ultrasound, was used as the reference standard against which all measurements were compared. Measurements were analyzed with intraclass correlation coefficient and Bland-Altman plots. All RTs were able to obtain a suitable longitudinal image for each patient in the study. Mean differences (SD) between MRI and ultrasound measurements obtained by RTs ranged from 3.5 (3.6) to 4.4 (4.23) mm and 0 (3.0) to 0.9 (2.5) mm on the anterior and posterior surface of the cervix, respectively. Intraclass correlation coefficient for absolute agreement between MRI and RTs was >0.9 for all posterior measurement points in the cervix and ranged from 0.41 to 0.92 on the anterior surface. Measurements were not statistically different between RTs at any measurement point. RTs with variable training attained high levels of interoperator reliability when using transabdominal ultrasound to obtain images and measurements of the uterus and cervix with brachytherapy applicators in situ. Access to training and use of a well-defined protocol assist in achieving these high levels of reliability. Copyright © 2016 American Brachytherapy Society. Published by Elsevier Inc. All rights reserved.

  11. Evolution of brachytherapy for prostate carcinoma

    International Nuclear Information System (INIS)

    Qin Lan

    2005-01-01

    Brachytherapy is one of the most main management to prostate carcinoma. This method has been rapidly accepted in clinical application since it is a convenient, little-traumatic, and outpatient therapy. With the development of techniques of production of radio-seeds, imaging modality and three-dimensional radiotherapy plan system, brachytherapy has been made a virtually progress in improving curative-effect and reducing damage to surrounding normal tissue. (authors)

  12. Monte Carlo model for a prototype CT-compatible, anatomically adaptive, shielded intracavitary brachytherapy applicator for the treatment of cervical cancer

    Energy Technology Data Exchange (ETDEWEB)

    Price, Michael J.; Gifford, Kent A.; Horton, John L. Jr.; Eifel, Patricia J.; Gillin, Michael T.; Lawyer, Ann A.; Mourtada, Firas [Department of Radiation Physics, University of Texas M. D. Anderson Cancer Center, 1220 Holcombe Boulevard, Houston, Texas 77030 and Graduate School of Biomedical Sciences, University of Texas-Houston, 6767 Bertner Avenue, Houston, Texas 77030 (United States); Department of Radiation Physics, University of Texas M. D. Anderson Cancer Center, 1220 Holcombe Boulevard, Houston, Texas 77030 (United States); Division of Radiation Oncology, University of Texas M. D. Anderson Cancer Center, 1220 Holcombe Boulevard, Houston, Texas 77030 and Graduate School of Biomedical Sciences, University of Texas-Houston, 6767 Bertner Avenue, Houston, Texas 77030 (United States); Department of Radiation Physics, University of Texas M. D. Anderson Cancer Center, 1220 Holcombe Boulevard, Houston, Texas 77030 and Graduate School of Biomedical Sciences, University of Texas-Houston, 6767 Bertner Avenue, Houston, Texas 77030 (United States); Department of Radiation Physics, University of Texas M. D. Anderson Cancer Center, 1220 Holcombe Boulevard, Houston, Texas 77030 (United States); Department of Radiation Physics, University of Texas M. D. Anderson Cancer Center, 1220 Holcombe Boulevard, Houston, Texas 77030 and Graduate School of Biomedical Sciences, University of Texas-Houston, 6767 Bertner Avenue, Houston, Texas 77030 (United States)

    2009-09-15

    Purpose: Current, clinically applicable intracavitary brachytherapy applicators that utilize shielded ovoids contain a pair of tungsten-alloy shields which serve to reduce dose delivered to the rectum and bladder during source afterloading. After applicator insertion, these fixed shields are not necessarily positioned to provide optimal shielding of these critical structures due to variations in patient anatomies. The authors present a dosimetric evaluation of a novel prototype intracavitary brachytherapy ovoid [anatomically adaptive applicator (A{sup 3})], featuring a single shield whose position can be adjusted with two degrees of freedom: Rotation about and translation along the long axis of the ovoid. Methods: The dosimetry of the device for a HDR {sup 192}Ir was characterized using radiochromic film measurements for various shield orientations. A MCNPX Monte Carlo model was developed of the prototype ovoid and integrated with a previously validated model of a v2 mHDR {sup 192}Ir source (Nucletron Co.). The model was validated for three distinct shield orientations using film measurements. Results: For the most complex case, 91% of the absolute simulated and measured dose points agreed within 2% or 2 mm and 96% agreed within 10% or 2 mm. Conclusions: Validation of the Monte Carlo model facilitates future investigations into any dosimetric advantages the use of the A{sup 3} may have over the current state of art with respect to optimization and customization of dose delivery as a function of patient anatomical geometries.

  13. Monte Carlo model for a prototype CT-compatible, anatomically adaptive, shielded intracavitary brachytherapy applicator for the treatment of cervical cancer

    International Nuclear Information System (INIS)

    Price, Michael J.; Gifford, Kent A.; Horton, John L. Jr.; Eifel, Patricia J.; Gillin, Michael T.; Lawyer, Ann A.; Mourtada, Firas

    2009-01-01

    Purpose: Current, clinically applicable intracavitary brachytherapy applicators that utilize shielded ovoids contain a pair of tungsten-alloy shields which serve to reduce dose delivered to the rectum and bladder during source afterloading. After applicator insertion, these fixed shields are not necessarily positioned to provide optimal shielding of these critical structures due to variations in patient anatomies. The authors present a dosimetric evaluation of a novel prototype intracavitary brachytherapy ovoid [anatomically adaptive applicator (A 3 )], featuring a single shield whose position can be adjusted with two degrees of freedom: Rotation about and translation along the long axis of the ovoid. Methods: The dosimetry of the device for a HDR 192 Ir was characterized using radiochromic film measurements for various shield orientations. A MCNPX Monte Carlo model was developed of the prototype ovoid and integrated with a previously validated model of a v2 mHDR 192 Ir source (Nucletron Co.). The model was validated for three distinct shield orientations using film measurements. Results: For the most complex case, 91% of the absolute simulated and measured dose points agreed within 2% or 2 mm and 96% agreed within 10% or 2 mm. Conclusions: Validation of the Monte Carlo model facilitates future investigations into any dosimetric advantages the use of the A 3 may have over the current state of art with respect to optimization and customization of dose delivery as a function of patient anatomical geometries.

  14. A new applicator system for afterloading brachytherapy of the uterine cervix

    International Nuclear Information System (INIS)

    Duehmke, E.; Busch, M. II; Kirschner, H.

    1990-01-01

    We developed a new application system for the intracavitary afterloading therapy of the cervix carcinoma. With this system special problems of the application as the possible perforation of the cervix uteri are prevented. (orig.) [de

  15. Oncentra brachytherapy planning system.

    Science.gov (United States)

    Yang, Jack

    2018-03-27

    In modern cancer management, treatment planning has progressed as a contemporary tool with all the advances in computing power in recent years. One of the advanced planning tools uses 3-dimensional (3D) data sets for accurate dose distributions in patient prescription. Among these planning processes, brachytherapy has been a very important part of a successful cancer management program, offering clinical benefits with specific or combined treatments with external beam therapy. In this chapter, we mainly discussed the Elekta Oncentra planning system, which is the main treatment planning tool for high-dose rate (HDR) modality in our facility and in many other facilities in the United States. HDR is a technically advanced form of brachytherapy; a high-intensity radiation source (3.6 mm in length) is delivered with step motor in submillimeter precision under computer guidance directly into the tumor areas while minimizing injury to surrounding normal healthy tissue. Oncentra planning is the key component to generate a deliverable brachytherapy procedure, which is executed on the microSelectron V3 remote afterloader treatment system. Creating a highly conformal plan can be a time-consuming task. The development of Oncentra software (version 4.5.3) offers a variety of useful tools that facilitate many of the clinical challenging tasks for planning, such as contouring and image reconstruction, as well as rapid planning calculations with dose and dose volume histogram analysis. Oncentra Brachy module creates workflow and optimizes the planning accuracy for wide varieties of clinical HDR treatments, such as skin, gynecologic (GYN), breast, prostate, and many other applications. The treatment file can also be transferred to the afterloader control station for speedy delivery. The design concept, calculation algorithms, and optimization modules presented some key characteristics to plan and treat the patients effectively and accurately. The dose distribution and accuracy of

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

    International Nuclear Information System (INIS)

    Nag, Subir; Chao, Clifford; Erickson, Beth; Fowler, Jeffery; Gupta, Nilendu; Martinez, Alvaro; Thomadsen, Bruce

    2002-01-01

    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

  17. Stress analysis studies in optimised 'D' shaped TOKAMAK magnet designs

    International Nuclear Information System (INIS)

    Diserens, N.J.

    1975-07-01

    A suite of computer programs TOK was developed which enabled simple data input to be used for computation of magnetic fields and forces in a toroidal system of coils with either D-shaped or circular cross section. An additional requirement was that input data to the Swansea stress analysis program FINESSE could be output from the TOK fields and forces program, and that graphical output from either program should be available. A further program was required to optimise the coil shape. This used the field calculating routines from the TOK program. The starting point for these studies was the proposed 40 coil Princeton design. The stresses resulting from three different shapes of D-coil were compared. (author)

  18. High-dose rate iridium-192 brachytherapy with flexible applicator. A trial toward decrease of stress during treatment and improvement of quality of life

    International Nuclear Information System (INIS)

    Inoue, Keiji; Kasahara, Kotaro; Karashima, Takashi; Inoue, Yuichiro; Kariya, Shinji; Inomata, Taisuke; Yoshida, Shoji; Shuin, Taro

    2001-01-01

    We tried to improve the materials and methods of high-dose rate Iridium-192 brachytherapy for localized prostate cancer and evaluated the stress during the treatment in 20 patients with whom the therapy was performed. Rigid applicators made of stainless steel of 1.6 mm in diameter were indwelt with a template as usual for 30 hours in 14 patients (group A). Flexible applicators made of polyoxymethylene rosin (POM) of 2.0 mm in diameter were indwelt without a template for 30 hours after the applicator insertion in 6 patients (group B). We made inquiries about lumbago, inconvenience and necessity of assistant help and sleep in the course of therapy, and urinary incontinence and erectile function after the course of therapy as the QOL. The stress during the course of therapy in the patients of group B was obviously less than that of group A. There were no significant differences in urinary incontinence and erectile function after the course of therapy between group A and B. In this study, our trial successfully reduced the stress during the course of therapy in the patients with localized prostate cancer in the course of high-dose rate Iridium-192 brachytherapy. (author)

  19. High-dose rate iridium-192 brachytherapy with flexible applicator. A trial toward decrease of stress during treatment and improvement of quality of life

    Energy Technology Data Exchange (ETDEWEB)

    Inoue, Keiji; Kasahara, Kotaro; Karashima, Takashi; Inoue, Yuichiro; Kariya, Shinji; Inomata, Taisuke; Yoshida, Shoji; Shuin, Taro [Kochi Medical School, Nankoku (Japan)

    2001-07-01

    We tried to improve the materials and methods of high-dose rate Iridium-192 brachytherapy for localized prostate cancer and evaluated the stress during the treatment in 20 patients with whom the therapy was performed. Rigid applicators made of stainless steel of 1.6 mm in diameter were indwelt with a template as usual for 30 hours in 14 patients (group A). Flexible applicators made of polyoxymethylene rosin (POM) of 2.0 mm in diameter were indwelt without a template for 30 hours after the applicator insertion in 6 patients (group B). We made inquiries about lumbago, inconvenience and necessity of assistant help and sleep in the course of therapy, and urinary incontinence and erectile function after the course of therapy as the QOL. The stress during the course of therapy in the patients of group B was obviously less than that of group A. There were no significant differences in urinary incontinence and erectile function after the course of therapy between group A and B. In this study, our trial successfully reduced the stress during the course of therapy in the patients with localized prostate cancer in the course of high-dose rate Iridium-192 brachytherapy. (author)

  20. 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, ...

  1. The importance of applicator design for intraluminal brachytherapy of rectal cancer

    International Nuclear Information System (INIS)

    Hansen, Johnny Witterseh; Jakobsen, Anders

    2006-01-01

    An important aspect of designing an applicator for radiation treatment of rectal cancer is the ability to minimize dose to the mucosa and noninvolved parts of the rectum wall. For this reason we investigated a construction of a flexible multichannel applicator with several channels placed along the periphery of a cylinder and a construction of a rigid cylinder with a central channel and interchangeable shields. Calculations of the dose gradient, dose homogeneity in the tumor, and shielding ability were performed for the two applicators in question. Furthermore, the influence on dose distribution around a flexible multichannel applicator from an unintended off-axis positioning of the source inside a bent channel was investigated by film measurements on a single bent catheter. Calculations showed that a single-channel applicator with interchangeable shields yields a higher degree of shielding and has a better dose homogeneity in the tumor volume than that of a multichannel applicator. A single-channel applicator with interchangeable shields was manufactured, and the influence of different size of shield angle on dose rate in front of and behind the shields was measured. While dose rate in front of the shield and shielding ability are closely independent of the size of the shield angle when measured 1 cm from the applicator surface, dose rate in more distant volumes will to some extent be influenced by shield angle due to volume scatter conditions

  2. Computed tomography-based treatment planning for high-dose-rate brachytherapy using the tandem and ring applicator: influence of applicator choice on organ dose and inter-fraction adaptive planning

    Directory of Open Access Journals (Sweden)

    Vishruta A. Dumane

    2017-06-01

    Full Text Available Three dimensional planning for high-dose-rate (HDR brachytherapy in cervical cancer has been highly recommended by consensus guidelines such as the American Brachytherapy Society (ABS and the Groupe Européen de Curiethérapie – European Society for Radiotherapy and Oncology (GEC-ESTRO. In this document, we describe our experience with computed tomography (CT-based planning using the tandem/ring applicator. We discuss the influence of applicator geometry on doses to organs at risk (OARs, namely the bladder, rectum, and sigmoid. Through example cases with dose prescribed to point A, we demonstrate how adaptive planning can help achieve constraints to the OARs as per guidelines.

  3. Long duration mild temperature hyperthermia and brachytherapy.

    Science.gov (United States)

    Armour, E P; Raaphorst, G P

    2004-03-01

    Combining long duration mild temperature hyperthermia (LDMH) and low dose-rate (LDR) brachytherapy to enhance therapeutic killing of cancer cells was proposed many years ago. The cellular and tumour research that supports this hypothesis is presented in this review. Research describing LDMH interaction with pulsed brachytherapy and high dose-rate brachytherapy using clinically relevant parameters are compared with LDMH/LDR brachytherapy. The mechanism by which LDMH sensitizes LDR has been established as the inhibition of sublethal damage repair. The molecular mechanisms have been shown to involve DNA repair enzymes, but the exact nature of these processes is still under investigation. The relative differences between LDMH interactions with human and rodent cells are presented to help in the understanding of possible roles of LDMH in clinical application. The role of LDMH in modifying tumour blood flow and its possible role in LDR sensitization of tumours is also presented. The positive aspects of LDMH-brachytherapy for clinical application are sixfold; (1) the thermal goals (temperature, time and volume) are achievable with currently available technology, (2) the hyperthermia by itself has no detectable toxic effects, (3) thermotolerance appears to play a minor if any role in radiation sensitization, (4) TER of around 2 can be expected, (5) hypoxic fraction may be decreased due to blood flow modification and (6) simultaneous chemotherapy may also be sensitized. Combined LDMH and brachytherapy is a cancer therapy that has established biological rationale and sufficient technical and clinical advancements to be appropriately applied. This modality is ripe for clinical testing.

  4. SU-F-J-163: In Vivo Quantification of Sequence Parameter Effect On Geometric Distortion Caused by Implanted Titanium Brachytherapy Applicator

    Energy Technology Data Exchange (ETDEWEB)

    Sullivan, T; Diak, A; Surucu, M; Yacoub, J; Harkenrider, M; Shea, S [Loyola University Chicago, Maywood, IL (United States)

    2016-06-15

    Purpose: The use of MR to plan and evaluate brachytherapy treatment for cervical cancer is increasing given the availability of MR conditional or safe applicators and MRI’s proven superiority to CT for characterizing soft tissue lesions. The titanium applicators, however, cause geometric distortions or imaging artifacts, which reduce the utility of MRI for dosimetry. We sought to quantify the observed volume of the same applicator on a previously optimized T2 sequence in comparison to the conventional T2 sequence and CT obtained for brachytherapy planning. Methods: Prior work with testing in phantoms showed that increases in readout bandwidth yielded reductions in artifact area and distortion measurements even with voxel increases. Following IRB approval, nine patients with titanium tandem & ovoid applicator (Varian Medical Systems) in place were scanned with a standard periprocedural protocol which included sagittal T2 fast spin echo (FSE) acquisition (res 0.98×0.78×4.0 mm{sup 3}; BW 200Hz). An additional T2-weighted FSE sequence (res 0.98×0.98×3–4 mm{sup 3}; BW500Hz) with increased readout bandwidth, readout voxel size, and echo train length was added to the protocol. Volume measurements of the applicator (from tip to cervical stop) were hand-segmented in Velocity AI 3.1 (Velocity Medical Solutions) for the two T2 FSE sequences and a planning CT obtained shortly after MRI. Differences were analyzed using a paired t-test. Results: Average apparent volumes of the applicator on standard T2 sequence, decreased bandwidth T2 sequence and CT were 5.922±1.283 cm{sup 3}, 4.544±1.524 cm3, and 2.304±0.509 cm{sup 3} respectively. Conclusion: Apparent volumes of a brachytherapy applicator can be compared in vivo. The modified sequence results in decreased apparent size of the cervical applicator. Both MR sequence volumes were larger than the planning CT, which was expected. Future work will focus on the diagnostic quality of the new sequence and quantifying any

  5. SU-E-T-322: A Dosimetric Comparison of PBI Brachytherapy Techniques: SAVI, Contura, and Tube and Button Applicators.

    Science.gov (United States)

    Park, S; Kamrava, M; Demanes, J

    2012-06-01

    To evaluate the dosimetry of partial breast irradiation brachytherapy techniques using the Strut Adjusted Volume Implant (SAVI), Contura, and Tube and Button (T&B) applicators. A total of 51 breast-cancer patients (23 SAVI, 6 Contura, and 22 T&B) were treated. The target was delineated following NSABP B-39 guidelines. 3D plans were optimized using the Inverse Planning Simulated Annealing algorithm to deliver 3.4 Gy per fraction to the target and minimize dose to organs at risk (OARs). Graphical optimization was then used to fine tune the final dose distribution. The minimum cavity-to-skin distance was measured. Target coverage (V90 and V95) and maximum dose (D0.1cc) to the OARs were evaluated. Dose homogeneity index (DHI = 1-V150/V100) was calculated. The average cavity-to-skin distances were 4.1 mm (0.5-9.6 mm, SAVI) and 11.7 mm (7.1-15.4 mm, Contura). The target-to-skin distance for the T&B cases was 8.7 mm (5.0-13.7 mm). The average V90 and V95 to the target were 96.8% and 94.5% (SAVI), 97.0% and 93.0% (Contura), 98.6% and 97.3% (T&B). The mean D0.1cc to the skin, ribs, and lung was 91.5%, 58.8%, 44.5% (SAVI), 93.1%, 51.3%, 40.5% (Contura), 69.1%, 41.5%, and 31.9% (T&B). The average V150 and V200 to the normal breast tissue were 30.4 cc and 14.9 cc (SAVI), 29.5 cc and 7.3 cc (Contura), 18.3 cc and 7.1 cc (T&B). The average DHI for the SAVI, Contura, and T&B cases was 0.55 (0.50-0.60), 0.70 (0.63-0.78), and 0.76 (0.74-0.79). All techniques provided clinically acceptable target coverage and dose to the OARs. The SAVI device provided a lower skin dose at close cavity-to-skin distances while providing excellent target coverage. However, the T&B and Contura applicators produced more homogeneous dose distribution (higher DHI) in the target than the SAVI. The correlations between dosimetric properties and follow-up mammogram results are under investigation. © 2012 American Association of Physicists in Medicine.

  6. Prostate cancer brachytherapy

    International Nuclear Information System (INIS)

    Abreu, Carlos Eduardo Vita; Silva, Joao L. F.; Srougi, Miguel; Nesrallah, Adriano

    1999-01-01

    The transperineal brachytherapy with 125 I/Pd 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

  7. MCNP modelling of vaginal and uterine applicators used in intracavitary brachytherapy and comparison with radiochromic film measurements

    Science.gov (United States)

    Ceccolini, E.; Gerardy, I.; Ródenas, J.; van Dycke, M.; Gallardo, S.; Mostacci, D.

    Brachytherapy is an advanced cancer treatment that is minimally invasive, minimising radiation exposure to the surrounding healthy tissues. Microselectron© Nucletron devices with 192Ir source can be used for gynaecological brachytherapy, in patients with vaginal or uterine cancer. Measurements of isodose curves have been performed in a PMMA phantom and compared with Monte Carlo calculations and TPS (Plato software of Nucletron BPS 14.2) evaluation. The isodose measurements have been performed with radiochromic films (Gafchromic EBT©). The dose matrix has been obtained after digitalisation and use of a dose calibration curve obtained with a 6 MV photon beam provided by a medical linear accelerator. A comparison between the calculated and the measured matrix has been performed. The calculated dose matrix is obtained with a simulation using the MCNP5 Monte Carlo code (F4MESH tally).

  8. Prostate brachytherapy - discharge

    Science.gov (United States)

    Implant therapy - prostate cancer - discharge; Radioactive seed placement - discharge ... You had a procedure called brachytherapy to treat prostate cancer. Your treatment lasted 30 minutes or more, ...

  9. Commissioning of a well type chamber for HDR and LDR brachytherapy applications: a review of methodology and outcomes.

    Science.gov (United States)

    Mukwada, Godfrey; Neveri, Gabor; Alkhatib, Zaid; Waterhouse, David K; Ebert, Martin

    2016-03-01

    For safe and accurate dose delivery in brachytherapy, associated equipment is subject to commissioning and ongoing quality assurance (QA). Many centres depend on the use of a well-type chamber ('well chamber') for performing brachytherapy dosimetry. Documentation of well chamber commissioning is scarce despite the important role the chamber plays in the whole brachytherapy QA process. An extensive and structured commissioning of the HDR 1000 plus well chamber (Standard Imaging Inc, Middleton WI) for HDR and LDR dosimetry was undertaken at Sir Charles Gairdner Hospital. The methodology and outcomes of this commissioning is documented and presented as a guideline to others involved in brachytherapy. The commissioning tests described include mechanical integrity, leakage current, directional dependence, response, length of uniform response, the influence of insert holders, ion collection efficiency, polarity effect, accuracy of measured air kerma strength (S(K)) or reference air kerma rate (K(R)) and baseline setting (for ongoing constancy checks). For the HDR 1000 plus well chamber, some of the insert holders modify the response curve. The measured sweet length was 2.5 cm which is within 0.5% of that specified by the manufacturer. Correction for polarity was negligible (0.9999) and ion recombination was small (0.9994). Directional dependence was small (less than 0.2%) and leakage current was negligible. The measured K(R) for (192)Ir agreed within 0.11% compared with a second well chamber of similar model and was within 0.5% of that determined via a free-in-air measurement method. Routine constancy checks over a year agreed with the baseline within 0.4%.

  10. The novel nomogram of Gleason sum upgrade: possible application for the eligible criteria of low dose rate brachytherapy.

    Science.gov (United States)

    Budäus, Lars; Graefen, Markus; Salomon, Georg; Isbarn, Hendrik; Lughezzani, Giovanni; Sun, Maxine; Chun, Felix K H; Schlomm, Thorsten; Steuber, Thomas; Haese, Alexander; Koellermann, Jens; Sauter, Guido; Fisch, Margit; Heinzer, Hans; Huland, Hartwig; Karakiewicz, Pierre I

    2010-10-01

    To examine the rate of Gleason sum upgrading (GSU) from a sum of 6 to a Gleason sum of ≥7 in patients undergoing radical prostatectomy (RP), who fulfilled the recommendations for low dose rate brachytherapy (Gleason sum 6, prostate-specific antigen ≤10 ng/mL, clinical stage ≤T2a and prostate volume ≤50 mL), and to test the performance of an existing nomogram for prediction of GSU in this specific cohort of patients. The analysis focused on 414 patients, who fulfilled the European Society for Therapeutic Radiation and Oncology and American Brachytherapy Society criteria for low dose rate brachytherapy (LD-BT) and underwent a 10-core prostate biopsy followed by RP. The rate of GSU was tabulated and the ability of available clinical and pathological parameters for predicting GSU was tested. Finally, the performance of an existing GSU nomogram was explored. The overall rate of GSU was 35.5%. When applied to LD-BT candidates, the existing nomogram was 65.8% accurate versus 70.8% for the new nomogram. In decision curve analysis tests, the new nomogram fared substantially better than the assumption that no patient is upgraded and better than the existing nomogram. GSU represents an important issue in LD-BT candidates. The new nomogram might improve patient selection for LD-BT and cancer control outcome by excluding patients with an elevated probability of GSU. © 2010 The Japanese Urological Association.

  11. MO-B-BRD-04: Sterilization for 3D Printed Brachytherapy Applicators

    International Nuclear Information System (INIS)

    Cunha, J.

    2015-01-01

    This session is designed so that the learning objectives are practical. The intent is that the attendee may take home an understanding of not just the technology, but also the logistical steps necessary to execute these 3D printing techniques in the clinic. Four practical 3D printing topics will be discussed: (i) Creating bolus and compensators for photon machines; (ii) tools for proton therapy; (iii) clinical applications in imaging; (iv) custom phantom design for clinic and research use. The use of 3D printers within the radiation oncology setting is proving to be a useful tool for creating patient specific bolus and compensators with the added benefit of cost savings. Creating the proper protocol is essential to ensuring that the desired effect is achieved and modeled in the treatment planning system. The critical choice of printer material (since it determines the interaction with the radiation) will be discussed. Selection of 3D printer type, design methods, verification of dose calculation, and the printing process will be detailed to give the basis for establishing your own protocol for electron and photon fields. A practical discussion of likely obstacles that may be encountered will be included. The diversity of systems and techniques in proton facilities leads to different facilities having very different requirements for beam modifying hardware and quality assurance devices. Many departments find the need to design and fabricate facility-specific equipment, making 3D printing an attractive technology. 3D printer applications in proton therapy will be discussed, including beam filters and compensators, and the design of proton therapy specific quality assurance tools. Quality control specific to 3D printing in proton therapy will be addressed. Advantages and disadvantages of different printing technology for these applications will also be discussed. 3D printing applications using high-resolution radiology-based imaging data will be presented. This data

  12. MO-B-BRD-04: Sterilization for 3D Printed Brachytherapy Applicators

    Energy Technology Data Exchange (ETDEWEB)

    Cunha, J. [UC San Francisco (United States)

    2015-06-15

    This session is designed so that the learning objectives are practical. The intent is that the attendee may take home an understanding of not just the technology, but also the logistical steps necessary to execute these 3D printing techniques in the clinic. Four practical 3D printing topics will be discussed: (i) Creating bolus and compensators for photon machines; (ii) tools for proton therapy; (iii) clinical applications in imaging; (iv) custom phantom design for clinic and research use. The use of 3D printers within the radiation oncology setting is proving to be a useful tool for creating patient specific bolus and compensators with the added benefit of cost savings. Creating the proper protocol is essential to ensuring that the desired effect is achieved and modeled in the treatment planning system. The critical choice of printer material (since it determines the interaction with the radiation) will be discussed. Selection of 3D printer type, design methods, verification of dose calculation, and the printing process will be detailed to give the basis for establishing your own protocol for electron and photon fields. A practical discussion of likely obstacles that may be encountered will be included. The diversity of systems and techniques in proton facilities leads to different facilities having very different requirements for beam modifying hardware and quality assurance devices. Many departments find the need to design and fabricate facility-specific equipment, making 3D printing an attractive technology. 3D printer applications in proton therapy will be discussed, including beam filters and compensators, and the design of proton therapy specific quality assurance tools. Quality control specific to 3D printing in proton therapy will be addressed. Advantages and disadvantages of different printing technology for these applications will also be discussed. 3D printing applications using high-resolution radiology-based imaging data will be presented. This data

  13. CT-image-based conformal brachytherapy of breast cancer. The significance of semi-3-D and 3-D treatment planning.

    Science.gov (United States)

    Polgár, C; Major, T; Somogyi, A; Takácsi-Nagy, Z; Mangel, L C; Forrai, G; Sulyok, Z; Fodor, J; Németh, G

    2000-03-01

    .1% with semi-3-D planning, however, it was increased by 16.2% with 3-D planning, compared to the 2-D planning. The application of clips into the tumor bed and the conformal (semi-3-D and 3-D) planning help to avoid geographical miss. CT is suitable for 3-D brachytherapy planning. Better local control with less side effects might be achieved with these new techniques. Conformal 3-D brachytherapy calls for new treatment planning concepts, taking the irregular 3-D shape of the target volume into account. The routine clinical application of image-based 3-D brachytherapy is a real aim in the very close future.

  14. Guidelines by the AAPM and GEC-ESTRO on the use of innovative brachytherapy devices and applications: Report of Task Group 167

    Energy Technology Data Exchange (ETDEWEB)

    Nath, Ravinder [Department of Therapeutic Radiology, School of Medicine, Yale University, New Haven, Connecticut 06510 (United States); Rivard, Mark J., E-mail: mark.j.rivard@gmail.com [Department of Radiation Oncology, School of Medicine, Tufts University, Boston, Massachusetts 02111 (United States); DeWerd, Larry A. [Accredited Dosimetry and Calibration Laboratory, University of Wisconsin, Madison, Wisconsin 53706 (United States); Dezarn, William A. [Department of Radiation Oncology, School of Medicine, Wake Forest University, Winston-Salem, North Carolina 27157 (United States); Thompson Heaton, H. [Hagerstown, Maryland 21740 (United States); Ibbott, Geoffrey S. [Department of Radiation Physics, University of Texas MD Anderson Cancer Center, Houston, Texas 77030 (United States); Meigooni, Ali S. [Comprehensive Cancer Centers of Nevada, Las Vegas, Nevada 89169 (United States); Ouhib, Zoubir [Radiation Oncology, Lynn Regional Cancer Center, Delray Beach, Florida 33484 (United States); Rusch, Thomas W. [Xoft, Inc., A Subsidiary of iCAD, Inc., San Jose, California 95134 (United States); Siebert, Frank-André [Clinic of Radiotherapy, Universitätsklinikum Schleswig-Holstein, Campus Kiel, Kiel 24105 (Germany); Venselaar, Jack L. M. [Department of Medical Physics and Engineering, Instituut Verbeeten, Tilburg LA 5000 (Netherlands)

    2016-06-15

    Although a multicenter, Phase III, prospective, randomized trial is the gold standard for evidence-based medicine, it is rarely used in the evaluation of innovative devices because of many practical and ethical reasons. It is usually sufficient to compare the dose distributions and dose rates for determining the equivalence of the innovative treatment modality to an existing one. Thus, quantitative evaluation of the dosimetric characteristics of innovative radiotherapy devices or applications is a critical part in which physicists should be actively involved. The physicist’s role, along with physician colleagues, in this process is highlighted for innovative brachytherapy devices and applications and includes evaluation of (1) dosimetric considerations for clinical implementation (including calibrations, dose calculations, and radiobiological aspects) to comply with existing societal dosimetric prerequisites for sources in routine clinical use, (2) risks and benefits from a regulatory and safety perspective, and (3) resource assessment and preparedness. Further, it is suggested that any developed calibration methods be traceable to a primary standards dosimetry laboratory (PSDL) such as the National Institute of Standards and Technology in the U.S. or to other PSDLs located elsewhere such as in Europe. Clinical users should follow standards as approved by their country’s regulatory agencies that approved such a brachytherapy device. Integration of this system into the medical source calibration infrastructure of secondary standard dosimetry laboratories such as the Accredited Dosimetry Calibration Laboratories in the U.S. is encouraged before a source is introduced into widespread routine clinical use. The American Association of Physicists in Medicine and the Groupe Européen de Curiethérapie-European Society for Radiotherapy and Oncology (GEC-ESTRO) have developed guidelines for the safe and consistent application of brachytherapy using innovative devices

  15. SU-F-BRA-05: Utility of the Combined Use of Two Types of HDR Sources with the Direction Modulation Brachytherapy (DMBT) Tandem Applicator for Cervical Cancer Treatment

    Energy Technology Data Exchange (ETDEWEB)

    Safigholi, H; Soliman, A; Song, W [Sunnybrook Research Institute, Sunnybrook Health Sciences Centre, U of T, Toronto, Ontario (Canada); Han, D [Sunnybrook Research Institute, Sunnybrook Health Sciences Centre, U of T, Toronto, Ontario (Canada); University of California, San Diego, La Jolla, CA (United States); Meigooni, A Soleimani [Comprehensive Cancer Center of Nevada, Las Vegas, Nevada (United States); Scanderbeg, D [UCSD Medical Center, La Jolla, CA (United States)

    2015-06-15

    Purpose: To maximize the dose to HRCTV while minimizing dose to the OARs, the combination of two HDR brachytherapy sources, 192-Ir and 169-Yb, used in combination with the recently-proposed novel direction modulated brachytherapy (DMBT) tandem applicator were examined. Methods: The DMBT tandem, made from nonmagnetic tungsten-alloy rod, with diameter of 5.4mm, has 6 symmetric peripheral holes of 1.3mm diameter. The 0.3mm thick bio-compatible plastic tubing wraps the tandem. MCNPX v.2.6 was used to simulate the mHDR 192-Ir V2 and 4140 HDR 169-Yb sources inside the DMBT applicator. Thought was by combining the higher energy 192-Ir (380keV) and lower energy 169-Yb (92.7keV) sources could create unprecedented level of dose conformality when combined with the high-degree intensity modulation capable DMBT tandem applicator. 3D dose matrices, with 1 mm3 resolution, were imported into an in-house-coded inverse optimization planning system to evaluate plan quality of 19 clinical patient cases. Prescription dose was 15Gy. All plans were normalized to receive the same HRCTV D90. Results: Generally, the use of dual sources produced better plans than using either of the sources alone, with significantly better performance in some patients. The mean D2cc for bladder, rectum, and sigmoid were 11.65±2.30Gy, 7.47±3.05Gy, and 9.84±2.48Gy for 192-Ir-only, respectively. For 169 -Yb-only, they were 11.67±2.26Gy, 7.44±3.02Gy, and 9.83±2.38Gy, respectively. The corresponding data for the dual sources were 11.51±2.24Gy, 7.30±3.00Gy, and 9.68 ±2.39Gy, respectively. The HRCTV D98 and V100 were 16.37±1.86Gy and 97.37±1.92Gy for Ir-192-only, respectively. For 169-Yb-only, they were 16.43±1.86Gy, and 97.51±1.91Gy, respectively. For the dual source, they were 16.42±1.87Gy and 97.47±1.93Gy, respectively. Conclusion: The plan quality improves, in some cases quite significantly, for when dual 192-Ir and 169-Yb sources are used in combination with highly intensity modulation capable

  16. Guidelines by the AAPM and GEC-ESTRO on the use of innovative brachytherapy devices and applications: Report of Task Group 167

    International Nuclear Information System (INIS)

    Nath, Ravinder; Rivard, Mark J.; DeWerd, Larry A.; Dezarn, William A.; Thompson Heaton, H.; Ibbott, Geoffrey S.; Meigooni, Ali S.; Ouhib, Zoubir; Rusch, Thomas W.; Siebert, Frank-André; Venselaar, Jack L. M.

    2016-01-01

    Although a multicenter, Phase III, prospective, randomized trial is the gold standard for evidence-based medicine, it is rarely used in the evaluation of innovative devices because of many practical and ethical reasons. It is usually sufficient to compare the dose distributions and dose rates for determining the equivalence of the innovative treatment modality to an existing one. Thus, quantitative evaluation of the dosimetric characteristics of innovative radiotherapy devices or applications is a critical part in which physicists should be actively involved. The physicist’s role, along with physician colleagues, in this process is highlighted for innovative brachytherapy devices and applications and includes evaluation of (1) dosimetric considerations for clinical implementation (including calibrations, dose calculations, and radiobiological aspects) to comply with existing societal dosimetric prerequisites for sources in routine clinical use, (2) risks and benefits from a regulatory and safety perspective, and (3) resource assessment and preparedness. Further, it is suggested that any developed calibration methods be traceable to a primary standards dosimetry laboratory (PSDL) such as the National Institute of Standards and Technology in the U.S. or to other PSDLs located elsewhere such as in Europe. Clinical users should follow standards as approved by their country’s regulatory agencies that approved such a brachytherapy device. Integration of this system into the medical source calibration infrastructure of secondary standard dosimetry laboratories such as the Accredited Dosimetry Calibration Laboratories in the U.S. is encouraged before a source is introduced into widespread routine clinical use. The American Association of Physicists in Medicine and the Groupe Européen de Curiethérapie-European Society for Radiotherapy and Oncology (GEC-ESTRO) have developed guidelines for the safe and consistent application of brachytherapy using innovative devices

  17. Accelerated partial breast irradiation utilizing balloon brachytherapy techniques

    International Nuclear Information System (INIS)

    Strauss, Jonathan B.; Dickler, Adam

    2009-01-01

    To overcome the barriers to BCT, methods of PBI in the setting of breast conservation have been explored. The method of PBI with the longest published follow-up is multi-catheter interstitial brachytherapy. Balloon-based brachytherapy with the MammoSite brachytherapy applicator was designed to simplify the brachytherapy procedure for PBI, enhance the reproducibility of the dosimetry, and improve patient comfort. The rates of local recurrence following PBI with the MammoSite applicator have been low, but there are few published reports and follow-up has been relatively short. The cosmetic outcomes and toxicity of MammoSite PBI are comparable to those seen after multicatheter-based PBI. Additional methods of balloon brachytherapy, including Xoft and SenoRx Contura have been developed. Finally, long-term follow-up after PBI is important for the welfare of individual patients and in order to establish the efficacy, late toxicity and cosmetic outcomes of this technique.

  18. Calculation of integrated biological response in brachytherapy

    International Nuclear Information System (INIS)

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

    1997-01-01

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

  19. Two-dimensional discrete ordinates photon transport calculations for brachytherapy dosimetry applications

    International Nuclear Information System (INIS)

    Daskalov, G.M.; Baker, R.S.; Little, R.C.; Rogers, D.W.O.; Williamson, J.F.

    2000-01-01

    The DANTSYS discrete ordinates computer code system is applied to quantitative estimation of water kerma rate distributions in the vicinity of discrete photon sources with energies in the 20- to 800-keV range in two-dimensional cylindrical r-z geometry. Unencapsulated sources immersed in cylindrical water phantoms of 40-cm diameter and 40-cm height are modeled in either homogeneous phantoms or shielded by Ti, Fe, and Pb filters with thicknesses of 1 and 2 mean free paths. The obtained dose results are compared with corresponding photon Monte Carlo simulations. A 210-group photon cross-section library for applications in this energy range is developed and applied, together with a general-purpose 42-group library developed at Los Alamos National Laboratory, for DANTSYS calculations. The accuracy of DANTSYS with the 42-group library relative to Monte Carlo exhibits large pointwise fluctuations from -42 to +84%. The major cause for the observed discrepancies is determined to be the inadequacy of the weighting function used for the 42-group library derivation. DANTSYS simulations with a finer 210-group library show excellent accuracy on and off the source transverse plane relative to Monte Carlo kerma calculations, varying from minus4.9 to 3.7%. The P 3 Legendre polynomial expansion of the angular scattering function is shown to be sufficient for accurate calculations. The results demonstrate that DANTSYS is capable of calculating photon doses in very good agreement with Monte Carlo and that the multigroup cross-section library and efficient techniques for mitigation of ray effects are critical for accurate discrete ordinates implementation

  20. SU-E-T-523: Investigation of Various MR-Compatible Shielding Materials for Direction Modulated Brachytherapy (DMBT) Tandem Applicator for Cervical Cancer Treatment

    Energy Technology Data Exchange (ETDEWEB)

    Safigholi, H; Soliman, A; Song, W [Sunnybrook Research Institute, Sunnybrook Health Sciences Centre, U of T, Toronto, Ontario (Canada); Han, D [Sunnybrook Research Institute, Sunnybrook Health Sciences Centre, U of T, Toronto, Ontario (Canada); University of California, San Diego, La Jolla, CA (United States); Meigooni, A Soleimani [Comprehensive Cancer Center of Nevada, Las Vegas, NV (United States); Scanderbeg, D [UCSD Medical Center, La Jolla, CA (United States)

    2015-06-15

    Purpose: To evaluate various shielding materials such as Gold (Au), Osmium (Os), Tantalum (Ta), and Tungsten (W) based alloys for use with a novel intensity modulation capable direction modulated brachytherapy (DMBT) tandem applicator for image guided cervical cancer HDR brachytherapy. Methods: The novel MRI-compatible DMBT tandem, made from nonmagnetic tungsten-alloy rod with diameter of 5.4 mm, has 6 symmetric peripheral holes of 1.3 mm diameter with 2.05 mm distance from the center for a high degree intensity modulation capacity. The 0.3 mm thickness of bio-compatible plastic tubing wraps the tandem. MCNPX was used for Monte Carlo simulations of the shields and the mHDR Ir-192 V2 source. MC-generated 3D dose matrices of different shielding materials of Au, Os, Ta, and W with 1 mm3 resolution were imported into an in-house-coded inverse optimization planning system to evaluate 19 clinical patient plans. Prescription dose was 15Gy. All plans were normalized to receive the same HRCTV D90. Results: In general, the plan qualities for various shielding materials were similar. The OAR D2cc for bladder was very similar for Au, Os, and Ta with 11.64±2.30Gy. For W, it was very close 11.65±2.30Gy. The sigmoid D2cc was 9.82±2.46Gy for Au and Os while it was 9.84±2.48Gy for Ta and W. The rectum D2cc was 7.44±3.06Gy for Au, 7.43±3.07Gy for Os, 7.48±3.05Gy for Ta, and 7.47±3.05Gy for W. The HRCTV D98 and V100 were very close with 16.37±1.87 Gy and 97.37±1.93 Gy, on average, respectively. Conclusion: Various MRI-compatible shielding alloys were investigated for the DMBT tandem applicator. The clinical plan qualities were not significantly different among these various alloys, however. Therefore, the candidate metals (or in combination) can be used to select best alloys for MRI image guided cervical cancer brachytherapy using the novel DMBT applicator that is capable of unprecedented level of intensity modulation.

  1. SU-E-T-523: Investigation of Various MR-Compatible Shielding Materials for Direction Modulated Brachytherapy (DMBT) Tandem Applicator for Cervical Cancer Treatment

    International Nuclear Information System (INIS)

    Safigholi, H; Soliman, A; Song, W; Han, D; Meigooni, A Soleimani; Scanderbeg, D

    2015-01-01

    Purpose: To evaluate various shielding materials such as Gold (Au), Osmium (Os), Tantalum (Ta), and Tungsten (W) based alloys for use with a novel intensity modulation capable direction modulated brachytherapy (DMBT) tandem applicator for image guided cervical cancer HDR brachytherapy. Methods: The novel MRI-compatible DMBT tandem, made from nonmagnetic tungsten-alloy rod with diameter of 5.4 mm, has 6 symmetric peripheral holes of 1.3 mm diameter with 2.05 mm distance from the center for a high degree intensity modulation capacity. The 0.3 mm thickness of bio-compatible plastic tubing wraps the tandem. MCNPX was used for Monte Carlo simulations of the shields and the mHDR Ir-192 V2 source. MC-generated 3D dose matrices of different shielding materials of Au, Os, Ta, and W with 1 mm3 resolution were imported into an in-house-coded inverse optimization planning system to evaluate 19 clinical patient plans. Prescription dose was 15Gy. All plans were normalized to receive the same HRCTV D90. Results: In general, the plan qualities for various shielding materials were similar. The OAR D2cc for bladder was very similar for Au, Os, and Ta with 11.64±2.30Gy. For W, it was very close 11.65±2.30Gy. The sigmoid D2cc was 9.82±2.46Gy for Au and Os while it was 9.84±2.48Gy for Ta and W. The rectum D2cc was 7.44±3.06Gy for Au, 7.43±3.07Gy for Os, 7.48±3.05Gy for Ta, and 7.47±3.05Gy for W. The HRCTV D98 and V100 were very close with 16.37±1.87 Gy and 97.37±1.93 Gy, on average, respectively. Conclusion: Various MRI-compatible shielding alloys were investigated for the DMBT tandem applicator. The clinical plan qualities were not significantly different among these various alloys, however. Therefore, the candidate metals (or in combination) can be used to select best alloys for MRI image guided cervical cancer brachytherapy using the novel DMBT applicator that is capable of unprecedented level of intensity modulation

  2. Advancements in brachytherapy

    DEFF Research Database (Denmark)

    Tanderup, Kari; Ménard, Cynthia; Polgar, Csaba

    2017-01-01

    Brachytherapy is a radiotherapy modality associated with a highly focal dose distribution. Brachytherapy treats the cancer tissue from the inside, and the radiation does not travel through healthy tissue to reach the target as with external beam radiotherapy techniques. The nature of brachytherap...

  3. SU-F-BRA-09: New Efficient Method for Xoft Axxent Electronic Brachytherapy Source Calibration by Pre-Characterizing Surface Applicators

    Energy Technology Data Exchange (ETDEWEB)

    Pai, S [iCAD Inc., Los Gatos, CA (United States)

    2015-06-15

    Purpose: The objective is to improve the efficiency and efficacy of Xoft™ Axxent™ electronic brachytherapy (EBT) calibration of the source & surface applicator using AAPM TG-61 formalism. Methods: Current method of Xoft EBT source calibration involves determination of absolute dose rate of the source in each of the four conical surface applicators using in-air chamber measurements & TG61 formalism. We propose a simplified TG-61 calibration methodology involving initial characterization of surface cone applicators. This is accomplished by calibrating dose rates for all 4 surface applicator sets (for 10 sources) which establishes the “applicator output ratios” with respect to the selected reference applicator (20 mm applicator). After the initial time, Xoft™ Axxent™ source TG61 Calibration is carried out only in the reference applicator. Using the established applicator output ratios, dose rates for other applicators will be calculated. Results: 200 sources & 8 surface applicator sets were calibrated cumulatively using a Standard Imaging A20 ion-chamber in accordance with manufacturer-recommended protocols. Dose rates of 10, 20, 35 & 50mm applicators were normalized to the reference (20mm) applicator. The data in Figure 1 indicates that the normalized dose rate variation for each applicator for all 200 sources is better than ±3%. The average output ratios are 1.11, 1.02 and 0.49 for the 10 mm,35 mm and 50 mm applicators, respectively, which are in good agreement with the manufacturer’s published output ratios of 1.13, 1.02 and 0.49. Conclusion: Our measurements successfully demonstrate the accuracy of a new calibration method using a single surface applicator for Xoft EBT sources and deriving the dose rates of other applicators. The accuracy of the calibration is improved as this method minimizes the source position variation inside the applicator during individual source calibrations. The new method significantly reduces the calibration time to less

  4. Evaluation of Artifacts and Distortions of Titanium Applicators on 3.0-Tesla MRI: Feasibility of Titanium Applicators in MRI-Guided Brachytherapy for Gynecological Cancer

    International Nuclear Information System (INIS)

    Kim, Yusung; Muruganandham, Manickam; Modrick, Joseph M.; Bayouth, John E.

    2011-01-01

    Purpose: The aim of this study was to characterize the levels of artifacts and distortions of titanium applicators on 3.0-Tesla magnetic resonance imaging (MRI). Methods and Materials: Fletcher-Suit-Delclos-style tandem and ovoids (T and O) and tandem and ring applicator (T and R) were examined. The quality assurance (QA) phantoms for each applicator were designed and filled with copper sulphate solution (1.5 g/l). The artifacts were quantified with the registration of corresponding computed tomography (CT) images. A favorable MR sequence was searched in terms of artifacts. Using the sequence, the artifacts were determined. The geometric distortions induced by the applicators were quantified through each registration of CT and MRI without applicators. The artifacts of T and O were also evaluated on in vivo MRI datasets of 5 patients. Results: T1-weighted MRI with 1-mm slice thickness was found as a favorable MR sequence. Applying the sequence, the artifacts at the tandem tip of T and O and T and R were determined as 1.5 ± 0.5 mm in a superior direction in phantom studies. In the ovoids of T and O, we found artifacts less than 1.5 ± 0.5 mm. The artifacts of a T and O tandem in vivo were found as less than 2.6 ± 1.3 mm on T1-weighted MRI, whereas less than 6.9 ± 3.4 mm on T2-weighted MRI. No more than 1.2 ± 0.6 mm (3.0 ± 1.5 mm) of distortions, due to a titanium applicator, were measured on T1-weighted MRI (T2-). Conclusion: In 3.0-Tesla MRI, we found the artifact widths at the tip of tandem were less than 1.5 ± 0.5 mm for both T and O and T and R when using T1-weighted MRI in phantom studies. However, exclusive 3.0-Tesla MRI-guided brachytherapy planning with a titanium applicator should be cautiously implemented.

  5. Localizing intracavitary brachytherapy applicators from cone-beam CT x-ray projections via a novel iterative forward projection matching algorithm

    International Nuclear Information System (INIS)

    Pokhrel, Damodar; Murphy, Martin J.; Todor, Dorin A.; Weiss, Elisabeth; Williamson, Jeffrey F.

    2011-01-01

    Purpose: To present a novel method for reconstructing the 3D pose (position and orientation) of radio-opaque applicators of known but arbitrary shape from a small set of 2D x-ray projections in support of intraoperative brachytherapy planning. Methods: The generalized iterative forward projection matching (gIFPM) algorithm finds the six degree-of-freedom pose of an arbitrary rigid object by minimizing the sum-of-squared-intensity differences (SSQD) between the computed and experimentally acquired autosegmented projection of the objects. Starting with an initial estimate of the object's pose, gIFPM iteratively refines the pose parameters (3D position and three Euler angles) until the SSQD converges. The object, here specialized to a Fletcher-Weeks intracavitary brachytherapy (ICB) applicator, is represented by a fine mesh of discrete points derived from complex combinatorial geometric models of the actual applicators. Three pairs of computed and measured projection images with known imaging geometry are used. Projection images of an intrauterine tandem and colpostats were acquired from an ACUITY cone-beam CT digital simulator. An image postprocessing step was performed to create blurred binary applicators only images. To quantify gIFPM accuracy, the reconstructed 3D pose of the applicator model was forward projected and overlaid with the measured images and empirically calculated the nearest-neighbor applicator positional difference for each image pair. Results: In the numerical simulations, the tandem and colpostats positions (x,y,z) and orientations (α,β,γ) were estimated with accuracies of 0.6 mm and 2 deg., respectively. For experimentally acquired images of actual applicators, the residual 2D registration error was less than 1.8 mm for each image pair, corresponding to about 1 mm positioning accuracy at isocenter, with a total computation time of less than 1.5 min on a 1 GHz processor. Conclusions: This work describes a novel, accurate, fast, and completely

  6. Localizing intracavitary brachytherapy applicators from cone-beam CT x-ray projections via a novel iterative forward projection matching algorithm

    Energy Technology Data Exchange (ETDEWEB)

    Pokhrel, Damodar; Murphy, Martin J.; Todor, Dorin A.; Weiss, Elisabeth; Williamson, Jeffrey F. [Department of Radiation Oncology, School of Medicine, Virginia Commonwealth University, Richmond, Virginia 23298 (United States)

    2011-02-15

    Purpose: To present a novel method for reconstructing the 3D pose (position and orientation) of radio-opaque applicators of known but arbitrary shape from a small set of 2D x-ray projections in support of intraoperative brachytherapy planning. Methods: The generalized iterative forward projection matching (gIFPM) algorithm finds the six degree-of-freedom pose of an arbitrary rigid object by minimizing the sum-of-squared-intensity differences (SSQD) between the computed and experimentally acquired autosegmented projection of the objects. Starting with an initial estimate of the object's pose, gIFPM iteratively refines the pose parameters (3D position and three Euler angles) until the SSQD converges. The object, here specialized to a Fletcher-Weeks intracavitary brachytherapy (ICB) applicator, is represented by a fine mesh of discrete points derived from complex combinatorial geometric models of the actual applicators. Three pairs of computed and measured projection images with known imaging geometry are used. Projection images of an intrauterine tandem and colpostats were acquired from an ACUITY cone-beam CT digital simulator. An image postprocessing step was performed to create blurred binary applicators only images. To quantify gIFPM accuracy, the reconstructed 3D pose of the applicator model was forward projected and overlaid with the measured images and empirically calculated the nearest-neighbor applicator positional difference for each image pair. Results: In the numerical simulations, the tandem and colpostats positions (x,y,z) and orientations ({alpha},{beta},{gamma}) were estimated with accuracies of 0.6 mm and 2 deg., respectively. For experimentally acquired images of actual applicators, the residual 2D registration error was less than 1.8 mm for each image pair, corresponding to about 1 mm positioning accuracy at isocenter, with a total computation time of less than 1.5 min on a 1 GHz processor. Conclusions: This work describes a novel, accurate

  7. Localizing intracavitary brachytherapy applicators from cone-beam CT x-ray projections via a novel iterative forward projection matching algorithm.

    Science.gov (United States)

    Pokhrel, Damodar; Murphy, Martin J; Todor, Dorin A; Weiss, Elisabeth; Williamson, Jeffrey F

    2011-02-01

    To present a novel method for reconstructing the 3D pose (position and orientation) of radio-opaque applicators of known but arbitrary shape from a small set of 2D x-ray projections in support of intraoperative brachytherapy planning. The generalized iterative forward projection matching (gIFPM) algorithm finds the six degree-of-freedom pose of an arbitrary rigid object by minimizing the sum-of-squared-intensity differences (SSQD) between the computed and experimentally acquired autosegmented projection of the objects. Starting with an initial estimate of the object's pose, gIFPM iteratively refines the pose parameters (3D position and three Euler angles) until the SSQD converges. The object, here specialized to a Fletcher-Weeks intracavitary brachytherapy (ICB) applicator, is represented by a fine mesh of discrete points derived from complex combinatorial geometric models of the actual applicators. Three pairs of computed and measured projection images with known imaging geometry are used. Projection images of an intrauterine tandem and colpostats were acquired from an ACUITY cone-beam CT digital simulator. An image postprocessing step was performed to create blurred binary applicators only images. To quantify gIFPM accuracy, the reconstructed 3D pose of the applicator model was forward projected and overlaid with the measured images and empirically calculated the nearest-neighbor applicator positional difference for each image pair. In the numerical simulations, the tandem and colpostats positions (x,y,z) and orientations (alpha, beta, gamma) were estimated with accuracies of 0.6 mm and 2 degrees, respectively. For experimentally acquired images of actual applicators, the residual 2D registration error was less than 1.8 mm for each image pair, corresponding to about 1 mm positioning accuracy at isocenter, with a total computation time of less than 1.5 min on a 1 GHz processor. This work describes a novel, accurate, fast, and completely automatic method to

  8. SU-C-BRD-02: A Team Focused Clinical Implementation and Failure Mode and Effects Analysis of HDR Skin Brachytherapy Using Valencia and Leipzig Surface Applicators

    International Nuclear Information System (INIS)

    Sayler, E; Harrison, A; Eldredge-Hindy, H; Dinome, J; Munro, S; Anne, R; Comber, E; Lockamy, V

    2014-01-01

    Purpose: and Leipzig applicators (VLAs) are single-channel brachytherapy surface applicators used to treat skin lesions up to 2cm diameter. Source dwell times can be calculated and entered manually after clinical set-up or ultrasound. This procedure differs dramatically from CT-based planning; the novelty and unfamiliarity could lead to severe errors. To build layers of safety and ensure quality, a multidisciplinary team created a protocol and applied Failure Modes and Effects Analysis (FMEA) to the clinical procedure for HDR VLA skin treatments. Methods: team including physicists, physicians, nurses, therapists, residents, and administration developed a clinical procedure for VLA treatment. The procedure was evaluated using FMEA. Failure modes were identified and scored by severity, occurrence, and detection. The clinical procedure was revised to address high-scoring process nodes. Results: Several key components were added to the clinical procedure to minimize risk probability numbers (RPN): -Treatments are reviewed at weekly QA rounds, where physicians discuss diagnosis, prescription, applicator selection, and set-up. Peer review reduces the likelihood of an inappropriate treatment regime. -A template for HDR skin treatments was established in the clinical EMR system to standardize treatment instructions. This reduces the chances of miscommunication between the physician and planning physicist, and increases the detectability of an error during the physics second check. -A screen check was implemented during the second check to increase detectability of an error. -To reduce error probability, the treatment plan worksheet was designed to display plan parameters in a format visually similar to the treatment console display. This facilitates data entry and verification. -VLAs are color-coded and labeled to match the EMR prescriptions, which simplifies in-room selection and verification. Conclusion: Multidisciplinary planning and FMEA increased delectability and

  9. Patterns of care for brachytherapy in Europe. Results in Spain.

    Science.gov (United States)

    López Torrecilla, J; Guedea, F; Heeren, G; Nissin, R; Ellison, T; Cottier, B

    2006-05-01

    In 2003 ESTRO began a project whose primary objective, was to make a map in the European area of infrastructures in technology and personnel for brachytherapy. A survey and a web site were elaborated. The survey was sent to the 76 Spanish Radiation Oncology departments in May 2003. By the end of 2003, 66 (86.8%) services had responded, 40 (71.4%) of which had brachytherapy. The services with brachytherapy treated 73.5% of the total patients, an average of 1,199 patients. The mean number of patients treated with brachytherapy by department was 135.5 and the number of applications was 265 annually. The average number of specialists was 7, 4 of them trained in brachytherapy. The average weekly work load of the radiation oncologists, physicists, and technicians was 22.6 h, 13.8 h and 21.0 h, respectively. The mean time dedicated to each patient by radiation oncologists, physicists and technicians was 9.2 h; 6.19 h; 7.2 h, respectively. The total number of afterloaders was 43 (22 HDR, 18 LDR, 3 PDR). The tumours most frequently treated with brachytherapy were gynaecological (56.24%), breast (14.2%) and prostate (11.7%). High dose rate was used in 47.46% of the patients and low dose rate in 47.24%. Between 1997 and 2002 there was an increase of 50.53% in patients treated with brachytherapy. The survey shows the brachytherapy resources and activity in Spain up to 2003. Increased use of brachytherapy in prostate tumours, prevalence of gynaecology brachytherapy and similar number of treatments with HDR and LDR are demonstrated in the Patterns of Care of Brachytherapy in Europe (PCBE) study in Spain.

  10. Biomaterial characteristics and application of silicone rubber and PVA hydrogels mimicked in organ groups for prostate brachytherapy.

    Science.gov (United States)

    Li, Pan; Jiang, Shan; Yu, Yan; Yang, Jun; Yang, Zhiyong

    2015-09-01

    It is definite that transparent material with similar structural characteristics and mechanical properties to human tissue is favorable for experimental study of prostate brachytherapy. In this paper, a kind of transparent polyvinyl alcohol (PVA) hydrogel and silicone rubber are developed as suitable substitutions for human soft tissue. Segmentation and 3D reconstruction of medical image are performed to manufacture the mould of organ groups through rapid prototyping technology. Micro-structure observation, force test and CCD deformation test have been conducted to investigate the structure and mechanical properties of PVA hydrogel used in organ group mockup. Scanning electron microscope (SEM) image comparison results show that PVA hydrogel consisting of 3 g PVA, 17 g de-ionized water, 80 g dimethyl-sulfoxide (DMSO), 4 g NaCl, 1.5 g NaOH, 3 g epichlorohydrin (ECH) and 7 freeze/thaw cycles reveals similar micro-structure to human prostate tissue. Through the insertion force comparison between organ group mockup and clinical prostate brachytherapy, PVA hydrogel and silicone rubber are found to have the same mechanical properties as prostate tissue and muscle. CCD deformation test results show that insertion force suffers a sharp decrease and a relaxation of tissue deformation appears when needle punctures the capsule of prostate model. The results exhibit that organ group mockup consisting of PVA hydrogel, silicone rubber, membrane and agarose satisfies the needs of prostate brachytherapy simulation in general and can be used to mimic the soft tissues in pelvic structure. Copyright © 2015 Elsevier Ltd. All rights reserved.

  11. 3D shape measurement of moving object with FFT-based spatial matching

    Science.gov (United States)

    Guo, Qinghua; Ruan, Yuxi; Xi, Jiangtao; Song, Limei; Zhu, Xinjun; Yu, Yanguang; Tong, Jun

    2018-03-01

    This work presents a new technique for 3D shape measurement of moving object in translational motion, which finds applications in online inspection, quality control, etc. A low-complexity 1D fast Fourier transform (FFT)-based spatial matching approach is devised to obtain accurate object displacement estimates, and it is combined with single shot fringe pattern prolometry (FPP) techniques to achieve high measurement performance with multiple captured images through coherent combining. The proposed technique overcomes some limitations of existing ones. Specifically, the placement of marks on object surface and synchronization between projector and camera are not needed, the velocity of the moving object is not required to be constant, and there is no restriction on the movement trajectory. Both simulation and experimental results demonstrate the effectiveness of the proposed technique.

  12. Endorectal high dose rate brachytherapy quality assurance

    International Nuclear Information System (INIS)

    Devic, S.; Vuong, T.; Evans, M.; Podgorsak, E.

    2008-01-01

    We describe our quality assurance method for preoperative high dose rate (HDR) brachytherapy of endorectal tumours. Reproduction of the treatment planning dose distribution on a daily basis is crucial for treatment success. Due to the cylindrical symmetry, two types of adjustments are necessary: applicator rotation and dose distribution shift along the applicator axis. (author)

  13. Risk assessment of component failure modes and human errors using a new FMECA approach: application in the safety analysis of HDR brachytherapy

    International Nuclear Information System (INIS)

    Giardina, M; Castiglia, F; Tomarchio, E

    2014-01-01

    Failure mode, effects and criticality analysis (FMECA) is a safety technique extensively used in many different industrial fields to identify and prevent potential failures. In the application of traditional FMECA, the risk priority number (RPN) is determined to rank the failure modes; however, the method has been criticised for having several weaknesses. Moreover, it is unable to adequately deal with human errors or negligence. In this paper, a new versatile fuzzy rule-based assessment model is proposed to evaluate the RPN index to rank both component failure and human error. The proposed methodology is applied to potential radiological over-exposure of patients during high-dose-rate brachytherapy treatments. The critical analysis of the results can provide recommendations and suggestions regarding safety provisions for the equipment and procedures required to reduce the occurrence of accidental events. (paper)

  14. The effect of tandem-ovoid titanium applicator on points A, B, bladder, and rectum doses in gynecological brachytherapy using 192Ir.

    Science.gov (United States)

    Sadeghi, Mohammad Hosein; Sina, Sedigheh; Mehdizadeh, Amir; Faghihi, Reza; Moharramzadeh, Vahed; Meigooni, Ali Soleimani

    2018-02-01

    The dosimetry procedure by simple superposition accounts only for the self-shielding of the source and does not take into account the attenuation of photons by the applicators. The purpose of this investigation is an estimation of the effects of the tandem and ovoid applicator on dose distribution inside the phantom by MCNP5 Monte Carlo simulations. In this study, the superposition method is used for obtaining the dose distribution in the phantom without using the applicator for a typical gynecological brachytherapy (superposition-1). Then, the sources are simulated inside the tandem and ovoid applicator to identify the effect of applicator attenuation (superposition-2), and the dose at points A, B, bladder, and rectum were compared with the results of superposition. The exact dwell positions, times of the source, and positions of the dosimetry points were determined in images of a patient and treatment data of an adult woman patient from a cancer center. The MCNP5 Monte Carlo (MC) code was used for simulation of the phantoms, applicators, and the sources. The results of this study showed no significant differences between the results of superposition method and the MC simulations for different dosimetry points. The difference in all important dosimetry points was found to be less than 5%. According to the results, applicator attenuation has no significant effect on the calculated points dose, the superposition method, adding the dose of each source obtained by the MC simulation, can estimate the dose to points A, B, bladder, and rectum with good accuracy.

  15. Simultaneous acquisition of 3D shape and deformation by combination of interferometric and correlation-based laser speckle metrology.

    Science.gov (United States)

    Dekiff, Markus; Berssenbrügge, Philipp; Kemper, Björn; Denz, Cornelia; Dirksen, Dieter

    2015-12-01

    A metrology system combining three laser speckle measurement techniques for simultaneous determination of 3D shape and micro- and macroscopic deformations is presented. While microscopic deformations are determined by a combination of Digital Holographic Interferometry (DHI) and Digital Speckle Photography (DSP), macroscopic 3D shape, position and deformation are retrieved by photogrammetry based on digital image correlation of a projected laser speckle pattern. The photogrammetrically obtained data extend the measurement range of the DHI-DSP system and also increase the accuracy of the calculation of the sensitivity vector. Furthermore, a precise assignment of microscopic displacements to the object's macroscopic shape for enhanced visualization is achieved. The approach allows for fast measurements with a simple setup. Key parameters of the system are optimized, and its precision and measurement range are demonstrated. As application examples, the deformation of a mandible model and the shrinkage of dental impression material are measured.

  16. Risk analysis of brachytherapy events

    International Nuclear Information System (INIS)

    Buricova, P.; Zackova, H.; Hobzova, L.; Novotny, J.; Kindlova, A.

    2005-01-01

    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)

  17. Definitive Brachytherapy for Kaposi's Sarcoma

    International Nuclear Information System (INIS)

    Williams, A.; Ezzell, G.; Zalupski, M.; Fontanesi, J.

    1996-01-01

    Purpose: To assess the efficacy and possible complications in patients diagnosed with Kaposi's sarcoma and treated with definitive brachytherapy. Methods and Materials: Between January, 1995 and December, 1995, four patients with Kaposi's sarcoma (KS) were treated with brachytherapy. Three patients, all with positive HIV status were treated using Iridium 192 (Ir-192) sources via a high-dose rate remote afterloader. One patient with endemic KS was treated using the application of catheters loaded with Californium 252. Eight sites were treated and included scalp, feet, nose, penis, hand, neck, and back. Dose rate for Ir-192 was 330cGy/fx to a total dose of 990cGy. The Californium was delivered as 100nGy/b.i.d. to a total dose of 900nGy. Follow-up as ranged from 2-6 months. Results: All four patients remain alive. Seven of eight sites have had complete clinical response and each patient has reported durable pain relief that has not subsided through last follow-up of 1/96. Two of eight sites, both treated with surface mold technique with Californium 252 developed moist desquamation. The remaining six sites did not demonstrate significant toxicity. Conclusion: Brachytherapy can offer Kaposi's sarcoma patients results that are equivalent to external beam radiation therapy, with minimal complications, a shorter treatment time and potential cost effectiveness

  18. Proficiency-based cervical cancer brachytherapy training.

    Science.gov (United States)

    Zhao, Sherry; Francis, Louise; Todor, Dorin; Fields, Emma C

    2018-04-25

    Although brachytherapy increases the local control rate for cervical cancer, there has been a progressive decline in its use. Furthermore, the training among residency programs for gynecologic brachytherapy varies considerably, with some residents receiving little to no training. This trend is especially concerning given the association between poor applicator placement and decline in local control. Considering the success of proficiency-based training in other procedural specialties, we developed and implemented a proficiency-based cervical brachytherapy training curriculum for our residents. Each resident placed tandem and ovoid applicators with attending guidance and again alone 2 weeks later using a pelvic model that was modified to allow for cervical brachytherapy. Plain films were taken of the pelvic model, and applicator placement quality was evaluated. Other evaluated metrics included retention of key procedural details, the time taken for each procedure and presession and postsession surveys to assess confidence. During the initial session, residents on average met 4.5 of 5 placement criteria, which improved to 5 the second session. On average, residents were able to remember 7.6 of the 8 key procedural steps. Execution time decreased by an average of 10.5%. Resident confidence with the procedure improved dramatically, from 2.6 to 4.6 of 5. Residents who had previously never performed a tandem and ovoid procedure showed greater improvements in these criteria than those who had. All residents strongly agreed that the training was helpful and wanted to participate again the following year. Residents participating in this simulation training had measurable improvements in the time to perform the procedure, applicator placement quality, and confidence. This curriculum is easy to implement and is of great value for training residents, and would be particularly beneficial in programs with low volume of cervical brachytherapy cases. Simulation programs could

  19. 3D Shape Perception in Posterior Cortical Atrophy: A Visual Neuroscience Perspective.

    Science.gov (United States)

    Gillebert, Céline R; Schaeverbeke, Jolien; Bastin, Christine; Neyens, Veerle; Bruffaerts, Rose; De Weer, An-Sofie; Seghers, Alexandra; Sunaert, Stefan; Van Laere, Koen; Versijpt, Jan; Vandenbulcke, Mathieu; Salmon, Eric; Todd, James T; Orban, Guy A; Vandenberghe, Rik

    2015-09-16

    Posterior cortical atrophy (PCA) is a rare focal neurodegenerative syndrome characterized by progressive visuoperceptual and visuospatial deficits, most often due to atypical Alzheimer's disease (AD). We applied insights from basic visual neuroscience to analyze 3D shape perception in humans affected by PCA. Thirteen PCA patients and 30 matched healthy controls participated, together with two patient control groups with diffuse Lewy body dementia (DLBD) and an amnestic-dominant phenotype of AD, respectively. The hierarchical study design consisted of 3D shape processing for 4 cues (shading, motion, texture, and binocular disparity) with corresponding 2D and elementary feature extraction control conditions. PCA and DLBD exhibited severe 3D shape-processing deficits and AD to a lesser degree. In PCA, deficient 3D shape-from-shading was associated with volume loss in the right posterior inferior temporal cortex. This region coincided with a region of functional activation during 3D shape-from-shading in healthy controls. In PCA patients who performed the same fMRI paradigm, response amplitude during 3D shape-from-shading was reduced in this region. Gray matter volume in this region also correlated with 3D shape-from-shading in AD. 3D shape-from-disparity in PCA was associated with volume loss slightly more anteriorly in posterior inferior temporal cortex as well as in ventral premotor cortex. The findings in right posterior inferior temporal cortex and right premotor cortex are consistent with neurophysiologically based models of the functional anatomy of 3D shape processing. However, in DLBD, 3D shape deficits rely on mechanisms distinct from inferior temporal structural integrity. Posterior cortical atrophy (PCA) is a neurodegenerative syndrome characterized by progressive visuoperceptual dysfunction and most often an atypical presentation of Alzheimer's disease (AD) affecting the ventral and dorsal visual streams rather than the medial temporal system. We applied

  20. 3D Shape Perception in Posterior Cortical Atrophy: A Visual Neuroscience Perspective

    Science.gov (United States)

    Gillebert, Céline R.; Schaeverbeke, Jolien; Bastin, Christine; Neyens, Veerle; Bruffaerts, Rose; De Weer, An-Sofie; Seghers, Alexandra; Sunaert, Stefan; Van Laere, Koen; Versijpt, Jan; Vandenbulcke, Mathieu; Salmon, Eric; Todd, James T.; Orban, Guy A.

    2015-01-01

    Posterior cortical atrophy (PCA) is a rare focal neurodegenerative syndrome characterized by progressive visuoperceptual and visuospatial deficits, most often due to atypical Alzheimer's disease (AD). We applied insights from basic visual neuroscience to analyze 3D shape perception in humans affected by PCA. Thirteen PCA patients and 30 matched healthy controls participated, together with two patient control groups with diffuse Lewy body dementia (DLBD) and an amnestic-dominant phenotype of AD, respectively. The hierarchical study design consisted of 3D shape processing for 4 cues (shading, motion, texture, and binocular disparity) with corresponding 2D and elementary feature extraction control conditions. PCA and DLBD exhibited severe 3D shape-processing deficits and AD to a lesser degree. In PCA, deficient 3D shape-from-shading was associated with volume loss in the right posterior inferior temporal cortex. This region coincided with a region of functional activation during 3D shape-from-shading in healthy controls. In PCA patients who performed the same fMRI paradigm, response amplitude during 3D shape-from-shading was reduced in this region. Gray matter volume in this region also correlated with 3D shape-from-shading in AD. 3D shape-from-disparity in PCA was associated with volume loss slightly more anteriorly in posterior inferior temporal cortex as well as in ventral premotor cortex. The findings in right posterior inferior temporal cortex and right premotor cortex are consistent with neurophysiologically based models of the functional anatomy of 3D shape processing. However, in DLBD, 3D shape deficits rely on mechanisms distinct from inferior temporal structural integrity. SIGNIFICANCE STATEMENT Posterior cortical atrophy (PCA) is a neurodegenerative syndrome characterized by progressive visuoperceptual dysfunction and most often an atypical presentation of Alzheimer's disease (AD) affecting the ventral and dorsal visual streams rather than the medial

  1. SU-G-TeP2-10: Feasibility of Newly Designed Applicator for High Dose Rate Brachytherapy Treatment of Patients with Vaginal Vault Recurrence

    Energy Technology Data Exchange (ETDEWEB)

    Lee, V; Wong, M; Chan, M; Cheung, S; Leung, R; Lee, K; Law, G; Tung, S [Tuen Mun Hospital (Hong Kong); Huang, X; Chui, E; Leung, K [The Chinese University of Hong Kong (Hong Kong); Kwong, D [The University of Hong Kong (Hong Kong)

    2016-06-15

    Purpose: To compare the dose of an in-house 3D-printed gynecology applicator (TMHGA) for vaginal vault recurrence of corpus cancer patients after operation for high dose rate brachytherapy treatment with commercially available applicators. Methods: A newly designed applicator is made from 3D-printing methods using ABSM30i. The isodose of the applicator is compared with Elekta multi-channel (MC) applicator and titanium Rotterdam applicator with coupling central tube and vaginal cylinder (RC). Three plans are created using three applicators in a CT set of water phantom. The applicators are anchored using the applicator library and implant library in the Elekta Oncentra treatment planning system (ver.4.5). The rectum is mimicked by creating a 2cm diameter cylinder, with a distance 1mm posteriorly away from the high risk CTV (HR-CTV). Similarly, the bladder is replicated by a 6cm diameter cylinder with distance 1mm anteriorly from the HR-CTV. Three plans are all normalized 1.5cm superior, 0.5cm anterior and 0.5cm posterior of the applicator surface. By fixing D90 of HR-CTV to 6Gy, the D2cc of rectum and bladder of three plans are compared. Results: The D2cc of the bladder for using TMHGA is lower than MC and RC by 14.0% and 11.9% respectively. While the D2cc of the rectum for using TMHGA is lower than MC and RC by 18.9% and 12.4% respectively. The total treatment time of TMHGA plan is shorter than MC and RC by 11.2% and 12.9%. Conclusion: The applicator created via 3D printing delivers a lower dose to the bladder and the rectum while keeping the same coverage to HR-CTV as other commercially available applicators. Additionally, the new applicator resulted in a reduction of treatment time, which is always welcome.

  2. SU-G-TeP2-10: Feasibility of Newly Designed Applicator for High Dose Rate Brachytherapy Treatment of Patients with Vaginal Vault Recurrence

    International Nuclear Information System (INIS)

    Lee, V; Wong, M; Chan, M; Cheung, S; Leung, R; Lee, K; Law, G; Tung, S; Huang, X; Chui, E; Leung, K; Kwong, D

    2016-01-01

    Purpose: To compare the dose of an in-house 3D-printed gynecology applicator (TMHGA) for vaginal vault recurrence of corpus cancer patients after operation for high dose rate brachytherapy treatment with commercially available applicators. Methods: A newly designed applicator is made from 3D-printing methods using ABSM30i. The isodose of the applicator is compared with Elekta multi-channel (MC) applicator and titanium Rotterdam applicator with coupling central tube and vaginal cylinder (RC). Three plans are created using three applicators in a CT set of water phantom. The applicators are anchored using the applicator library and implant library in the Elekta Oncentra treatment planning system (ver.4.5). The rectum is mimicked by creating a 2cm diameter cylinder, with a distance 1mm posteriorly away from the high risk CTV (HR-CTV). Similarly, the bladder is replicated by a 6cm diameter cylinder with distance 1mm anteriorly from the HR-CTV. Three plans are all normalized 1.5cm superior, 0.5cm anterior and 0.5cm posterior of the applicator surface. By fixing D90 of HR-CTV to 6Gy, the D2cc of rectum and bladder of three plans are compared. Results: The D2cc of the bladder for using TMHGA is lower than MC and RC by 14.0% and 11.9% respectively. While the D2cc of the rectum for using TMHGA is lower than MC and RC by 18.9% and 12.4% respectively. The total treatment time of TMHGA plan is shorter than MC and RC by 11.2% and 12.9%. Conclusion: The applicator created via 3D printing delivers a lower dose to the bladder and the rectum while keeping the same coverage to HR-CTV as other commercially available applicators. Additionally, the new applicator resulted in a reduction of treatment time, which is always welcome.

  3. American brachytherapy society (ABS) consensus guidelines for brachytherapy of esophageal cancer

    International Nuclear Information System (INIS)

    Gaspar, Laurie E.; Nag, Subir; Herskovic, Arnold; Mantravadi, Rao; Speiser, Burton

    1997-01-01

    Introduction: There is wide variation in the indications, treatment regimens, and dosimetry for brachytherapy in the treatment of cancer of the esophagus. No guidelines for optimal therapy currently exist. Methods and Materials: Utilizing published reports and clinical experience, representatives of the Clinical Research Committee of the American Brachytherapy Society (ABS) formulated guidelines for brachytherapy in esophageal cancer. Results: Recommendations were made for brachytherapy in the definitive and palliative treatment of esophageal cancer. (A) Definitive treatment: Good candidates for brachytherapy include patients with unifocal thoracic adeno- or squamous cancers ≤ 10 cm in length, with no evidence of intra-abdominal or metastatic disease. Contraindications include tracheal or bronchial involvement, cervical esophagus location, or stenosis that cannot be bypassed. The esophageal brachytherapy applicator should have an external diameter of 6-10 mm. If 5FU-based chemotherapy and 45-50-Gy external beam are used, recommended brachytherapy is either: (i) HDR 10 Gy in two weekly fractions of 5 Gy each; or (ii) LDR 20 Gy in a single course at 0.4-1 Gy/hr. All doses are specified 1 cm from the midsource or middwell position. Brachytherapy should follow external beam radiation therapy and should not be given concurrently with chemotherapy. (B) Palliative treatment: Patients with adeno- or squamous cancers of the thoracic esophagus with distant metastases or unresectable local disease progression/recurrence after definitive radiation treatment should be considered for brachytherapy with palliative intent. After limited dose (30 Gy) EBRT, the recommended brachytherapy is either: (i) HDR 10-14 Gy in one or two fractions; or (ii) LDR 20-25 Gy in a single course at 0.4-1 Gy/hr. The need for external beam radiation in newly diagnosed patients with a life expectancy of less than 3 months is controversial. In these cases, HDR of 15-20 Gy in two to four fractions or

  4. SU-E-T-297: Dosimetric Assessment of An Air-Filled Balloon Applicator in HDR Vaginal Cuff Brachytherapy Using the Monte Carlo Method

    Energy Technology Data Exchange (ETDEWEB)

    Jiang, H; Lee, Y; Pokhrel, D; Badkul, R [University of Kansas Hospital, Kansas City, KS (United States)

    2015-06-15

    Purpose: As an alternative to cylindrical applicators, air inflated balloon applicators have been introduced into HDR vaginal cuff brachytherapy treatment to achieve sufficient dose to vagina mucosa as well as to spare rectum and bladder. In general, TG43 formulae based treatment planning systems do not take into account tissue inhomogeneity, and air in the balloon applicator can cause higher delivered dose to mucosa than treatment plan reported. We investigated dosimetric effect of air in balloon applicator using the Monte Carlo method. Methods: The thirteen-catheter Capri applicator with a Nucletron Ir-192 seed was modeled for various balloon diameters (2cm to 3.5cm) using the MCNP Monte Carlo code. Ir-192 seed was placed in both central and peripheral catheters to replicate real patient situations. Existence of charged particle equilibrium (CPE) with air balloon was evaluated by comparing kerma and dose at various distances (1mm to 70mm) from surface of air-filled applicator. Also mucosa dose by an air-filled applicator was compared with by a water-filled applicator to evaluate dosimetry accuracy of planning system without tissue inhomogeneity correction. Results: Beyond 1mm from air/tissue interface, the difference between kerma and dose was within 2%. CPE (or transient CPE) condition was deemed existent, and in this region no electron transport was necessary in Monte Carlo simulations. At 1mm or less, the deviation of dose from kerma became more apparent. Increase of dose to mucosa depended on diameter of air balloon. The increment of dose to mucosa was 2.5% and 4.3% on average for 2cm and 3.5cm applicators, respectively. Conclusion: After introduction of air balloon applicator, CPE fails only at the proximity of air/tissue interface. Although dose to mucosa is increased, there is no significant dosimetric difference (<5%) between air and water filled applicators. Tissue inhomogeneity correction is not necessary for air-filled applicators.

  5. SU-E-T-297: Dosimetric Assessment of An Air-Filled Balloon Applicator in HDR Vaginal Cuff Brachytherapy Using the Monte Carlo Method

    International Nuclear Information System (INIS)

    Jiang, H; Lee, Y; Pokhrel, D; Badkul, R

    2015-01-01

    Purpose: As an alternative to cylindrical applicators, air inflated balloon applicators have been introduced into HDR vaginal cuff brachytherapy treatment to achieve sufficient dose to vagina mucosa as well as to spare rectum and bladder. In general, TG43 formulae based treatment planning systems do not take into account tissue inhomogeneity, and air in the balloon applicator can cause higher delivered dose to mucosa than treatment plan reported. We investigated dosimetric effect of air in balloon applicator using the Monte Carlo method. Methods: The thirteen-catheter Capri applicator with a Nucletron Ir-192 seed was modeled for various balloon diameters (2cm to 3.5cm) using the MCNP Monte Carlo code. Ir-192 seed was placed in both central and peripheral catheters to replicate real patient situations. Existence of charged particle equilibrium (CPE) with air balloon was evaluated by comparing kerma and dose at various distances (1mm to 70mm) from surface of air-filled applicator. Also mucosa dose by an air-filled applicator was compared with by a water-filled applicator to evaluate dosimetry accuracy of planning system without tissue inhomogeneity correction. Results: Beyond 1mm from air/tissue interface, the difference between kerma and dose was within 2%. CPE (or transient CPE) condition was deemed existent, and in this region no electron transport was necessary in Monte Carlo simulations. At 1mm or less, the deviation of dose from kerma became more apparent. Increase of dose to mucosa depended on diameter of air balloon. The increment of dose to mucosa was 2.5% and 4.3% on average for 2cm and 3.5cm applicators, respectively. Conclusion: After introduction of air balloon applicator, CPE fails only at the proximity of air/tissue interface. Although dose to mucosa is increased, there is no significant dosimetric difference (<5%) between air and water filled applicators. Tissue inhomogeneity correction is not necessary for air-filled applicators

  6. BEDVH--A method for evaluating biologically effective dose volume histograms: Application to eye plaque brachytherapy implants

    International Nuclear Information System (INIS)

    Gagne, Nolan L.; Leonard, Kara L.; Huber, Kathryn E.; Mignano, John E.; Duker, Jay S.; Laver, Nora V.; Rivard, Mark J.

    2012-01-01

    Purpose: A method is introduced to examine the influence of implant duration T, radionuclide, and radiobiological parameters on the biologically effective dose (BED) throughout the entire volume of regions of interest for episcleral brachytherapy using available radionuclides. This method is employed to evaluate a particular eye plaque brachytherapy implant in a radiobiological context. Methods: A reference eye geometry and 16 mm COMS eye plaque loaded with 103 Pd, 125 I, or 131 Cs sources were examined with dose distributions accounting for plaque heterogeneities. For a standardized 7 day implant, doses to 90% of the tumor volume ( TUMOR D 90 ) and 10% of the organ at risk volumes ( OAR D 10 ) were calculated. The BED equation from Dale and Jones and published α/β and μ parameters were incorporated with dose volume histograms (DVHs) for various T values such as T = 7 days (i.e., TUMOR 7 BED 10 and OAR 7 BED 10 ). By calculating BED throughout the volumes, biologically effective dose volume histograms (BEDVHs) were developed for tumor and OARs. Influence of T, radionuclide choice, and radiobiological parameters on TUMOR BEDVH and OAR BEDVH were examined. The nominal dose was scaled for shorter implants to achieve biological equivalence. Results: TUMOR D 90 values were 102, 112, and 110 Gy for 103 Pd, 125 I, and 131 Cs, respectively. Corresponding TUMOR 7 BED 10 values were 124, 140, and 138 Gy, respectively. As T decreased from 7 to 0.01 days, the isobiologically effective prescription dose decreased by a factor of three. As expected, TUMOR 7 BEDVH did not significantly change as a function of radionuclide half-life but varied by 10% due to radionuclide dose distribution. Variations in reported radiobiological parameters caused TUMOR 7 BED 10 to deviate by up to 46%. Over the range of OAR α/β values, OAR 7 BED 10 varied by up to 41%, 3.1%, and 1.4% for the lens, optic nerve, and lacrimal gland, respectively. Conclusions: BEDVH permits evaluation of the

  7. 137Cs - Brachytherapy sources : a technology scenario

    International Nuclear Information System (INIS)

    Varma, R.N.

    2001-01-01

    Cancer has emerged as one of the major cause of morbidity and mortality all over the world. India houses world's second largest population and registers 4-5 lakhs new cancer cases every year. Cancer of cervix is most common form of malignancy among Indian women. Radiation therapy, especially intracavity brachytherapy in conjunction with other modalities like surgery, chemotherapy has been found to be highly effective for the management and control of cervical carcinoma at all stages. A technology has been developed indigenously for the fabrication of 137 Cs sources for brachytherapy applications

  8. A survey of current clinical practice in permanent and temporary prostate brachytherapy: 2010 update.

    Science.gov (United States)

    Buyyounouski, Mark K; Davis, Brian J; Prestidge, Bradley R; Shanahan, Thomas G; Stock, Richard G; Grimm, Peter D; Demanes, D Jeffrey; Zaider, Marco; Horwitz, Eric M

    2012-01-01

    To help establish patterns of care and standards of care of interstitial permanent low-dose-rate (LDR) and temporary high-dose-rate brachytherapy for prostate cancer and to compare the results with a similar 1998 American Brachytherapy Society (ABS) survey. A comprehensive questionnaire intended to survey specific details of current clinical brachytherapy practice was provided to the participants of the seventh ABS Prostate Brachytherapy School. Responses were tabulated and descriptive statistics are reported. Sixty-five brachytherapy practitioners responded to the survey. Eighty-nine percent (89%) of respondents performed LDR and 49% perform high-dose-rate brachytherapy. The median number of years of experience for LDR brachytherapists increased from 5 to 10 years over the course of the 12 years since the preceding survey. Compared with the first ABS, a smaller proportion of respondents received formal brachytherapy residency training (43% vs. 56%) or formal "hands-on" brachytherapy training (15% vs. 63%). There has been a marked decline in the utilization of the Mick applicator (Mick Radio-Nuclear Instruments, Inc., Mount Vernon, NY, USA) (60% vs. 28%) and an increase in the use of stranded seeds (40% vs. 11%). Compliance with postimplant dosimetry was higher in the 2010 survey. This survey does suggest an evolution in the practice of LDR brachytherapy since 1998 and aids in identifying aspects that require further progress or investigation. ABS guidelines and other practice recommendations appear to impact the practice of brachytherapy. Copyright © 2012 American Brachytherapy Society. Published by Elsevier Inc. All rights reserved.

  9. Radioactive sources in brachytherapy:

    OpenAIRE

    Burger, Janez

    2003-01-01

    Background. In modern brachytherapy, a greast step forward was made in the 1960s in France with the introduction of new radioactive isotopes and new techniques. These innovations spread rapidly across Europe, though no single dosimetry standard had been set by then. In the new millennium, the advances in brachytherapy are further stimulated by the introduction of 3-D imaging techniques and the latest after loading irradiation equipment that use point sources. The international organiyation IC...

  10. High-dose-rate-intracavitary brachytherapy applications and the difference in the bladder and rectum doses: A study from rural centre of Maharashatra, India

    Directory of Open Access Journals (Sweden)

    Jain Vandana

    2007-01-01

    Full Text Available Aim : To report the difference in the bladder and rectum doses with different applications by the radiotherapists in the same patient of the carcinoma of the uterine cervix treated by multiple fractions of high-dose-rate (HDR intracavitary brachytherapy (ICBT. Materials and Methods : Between January 2003 to December 2004, a total of 60 cases of the carcinoma uterine cervix were selected randomly for the retrospective analyses. All 60 cases were grouped in six groups according to the treating radiotherapist who did the HDR-ICBT application. Three radiotherapists were considered for this study, named A, B and C. Ten cases for each radiotherapist in whom all three applications were done by the same radiotherapist. And 10 cases for each radiotherapist with shared applications in the same patient (A+B, A+C and B+C. The bladder and rectal doses were calculated in reference to point "A" dose and were limited to 80% of prescribed point "A" dose, as per ICRU-38 recommendations. Received dose grouped in three groups- less then 80% (< 80%, 80-100% and above 100% (>100%. A total of 180 applications for 60 patients were calculated for the above analyses. Results : There is a lot of difference in the bladder and rectal doses with the application by the different radiotherapists, even in the same patient with multiple fractions of HDR-ICBT. Applications by ′A′ radiotherapist were within the limits in the self as well as in the shared groups more number of times, by ′B′ radiotherapist was more times exceeding the limit and by ′C′ radiotherapist doses were in between the A and B. Discussion and Conclusion : For the rectal and bladder doses most important factors are patient′s age, disease stage, duration between EBRT and HDR-ICRT and patient anatomy, but these differences can be minimized to some extent by careful application, proper packing and proper fixation.

  11. Variations of intracavitary applicator geometry during multiple HDR brachytherapy insertions in carcinoma cervix and its influence on reporting as per ICRU report 38

    International Nuclear Information System (INIS)

    Datta, Niloy Ranjan; Kumar, Shaleen; Das, Koilpillai Joseph Maria; Pandey, Chandra Mani; Halder, Shikha; Ayyagari, Sunder

    2001-01-01

    Purpose: This paper examines the extent of variation in the applicator geometry during multiple high dose rate (HDR) intracavitary brachytherapy (ICBT) applications and its impact on reporting as per ICRU report 38. Materials and methods: Eighty orthogonal radiographs from 20 consecutive patients of carcinoma cervix (FIGO stages, IIA-IIIB) having four HDR ICBT applications of 6 Gy each at weekly intervals following teletherapy were evaluated. The applicator consisted of a flexible intrauterine tandem (IUT) independent of the ovoid assembly. The applicator geometry was evaluated in terms of: α angle, β angle, intrauterine length (IUTL), interovoid (IOV), os to right ovoid (ORT) and os to left ovoid (OLT) distances along with vertical (VDL) and anteroposterior displacements (ADL) of the os with respect to the ovoids. The Cartesian co-ordinates (X, Y, and Z) of the IUT tip, centre of both ovoids and os were also measured. Doses to right point A (ARD), left point A (ALD), along with a reference volume of 6 Gy for ICRU height (IRH), width (IRW), thickness (IRT) and volume (IRV) were estimated for each application. Results: Highly significant differences (P<0.001) between four insertions in any given patient across 20 patients for α angle, β angle, IUTL, IOV, ORT, VDL, co-ordinates of the IUT, ovoids and os were observed, except for ADL (P=0.041) and OLT (P=0.247). As a consequence, variations were observed in ARD (P=0.027), ALD (P=0.017); IRH, IRW, IRT and IRV (all P<0.001). Applicator factors which influenced the various dose specification parameters were: β angle and ORT for both ARD and ALD; UTLN, VDL and ORT for IRH; UTLN and IOV for IRW; UTLN for IRT and VDL for the 6 Gy IRV. Conclusions: A significant variation of the applicator geometry and its movement was observed in patients undergoing multiple HDR ICBT. This could have implications for reporting dose and volume specifications as required by ICRU report 38

  12. SU-F-19A-12: Split-Ring Applicator with Interstitial Needle for Improved Volumetric Coverage in HDR Brachytherapy for Cervical Cancer

    Energy Technology Data Exchange (ETDEWEB)

    Sherertz, T; Ellis, R; Colussi, V; Mislmani, M; Traughber, B; Herrmann, K; Podder, T [University Hospitals Case Medical Center, Cleveland, OH (United States)

    2014-06-15

    Purpose: To evaluate volumetric coverage of a Mick Radionuclear titanium Split-Ring applicator (SRA) with/without interstitial needle compared to an intracavitary Vienna applicator (VA), interstitial-intracavitary VA, and intracavitary ring and tandem applicator (RTA). Methods: A 57 year-old female with FIGO stage IIB cervical carcinoma was treated following chemoradiotherapy (45Gy pelvic and 5.4Gy parametrial boost) with highdose- rate (HDR) brachytherapy to 30Gy in 5 fractions using a SRA. A single interstitial needle was placed using the Ellis Interstitial Cap for the final three fractions to increase coverage of left-sided gross residual disease identified on 3T-MRI. High-risk (HR) clinical target volume (CTV) and intermediate-risk (IR) CTV were defined using axial T2-weighted 2D and 3D MRI sequences (Philips PET/MRI unit). Organs-at-risks (OARs) were delineated on CT. Oncentra planning system was used for treatment optimization satisfying GEC-ESTRO guidelines for target coverage and OAR constraints. Retrospectively, treatment plans (additional 20 plans) were simulated using intracavitary SRA (without needle), intracavitary VA (without needle), interstitial-intracavitary VA, and intracavitary RTA with this same patient case. Plans were optimized for each fraction to maintain coverage to HR-CTV. Results: Interstitial-intracavitary SRA achieved the following combined coverage for external radiation and brachytherapy (EQD2): D90 HR-CTV =94.6Gy; Bladder-2cc =88.9Gy; Rectum-2cc =65.1Gy; Sigmoid-2cc =48.9Gy; Left vaginal wall (VW) =103Gy, Right VW =99.2Gy. Interstitial-intracavitary VA was able to achieve identical D90 HR-CTV =94.6Gy, yet Bladder-2cc =91.9Gy (exceeding GEC-ESTRO recommendations of 2cc<90Gy) and Left VW =120.8Gy and Right VW =115.5Gy. Neither the SRA nor VA without interstitial needle could cover HR-CTV adequately without exceeding dose to Bladder-2cc. Conventional RTA was unable to achieve target coverage for the HR-CTV >80Gy without severely

  13. SU-G-201-11: Exploring the Upper Limits of Dose Sculpting Capacity of the Novel Direction Modulated Brachytherapy (DMBT) Tandem Applicator

    International Nuclear Information System (INIS)

    Han, D; Safigholi, H; Soliman, A; Song, W

    2016-01-01

    Purpose: To explore and quantify the upper limits in dose sculpting capacity of the novel direction modulated brachytherapy (DMBT) tandem applicator compared with conventional tandem design for "1"9"2Ir-based HDR planning. Methods: The proposed DMBT tandem applicator is designed for image-guided adaptive brachytherapy (IGABT), especially MRI, of cervical cancer. It has 6 peripheral holes of 1.3-mm width, grooved along a 5.4-mm diameter nonmagnetic tungsten alloy rod of density 18.0 g/cc, capable of generating directional dose profiles – leading to enhanced dose sculpting capacity through inverse planning. The external dimensions are identical to that of conventional tandem design to ensure clinical compatibility. To explore the expansive dose sculpting capacity, we constructed a hypothetical circular target with 20-mm radius and positioned the DMBT and conventional tandems at the center. We then incrementally shifted the positions laterally away from the center of up to 15 mm, at 1-mm steps. The in-house coded gradient projection-based inverse planning system was then used to generate inverse optimized plans ensuring identical V100=100% coverage. Conformity index (CI) was calculated for all plans. Results: Overall, the DMBT tandem generates more conformal dose distributions than conventional tandem for all lateral positional shifts of 0-15 mm (CI=0.91–0.52 and 0.99–0.34, respectively), with an exception at the central position due to the ideal circular dose distribution, generated by the "1"9"2Ir, fitting tightly around the circular target (CI = 0.91 and 0.99, respectively). The DMBT tandem is able to generate dose conformity of CI>0.8 at up to 6-mm positional shift while the conventional tandem violates this past 2-mm shift. Also, the CI ratio (=DMBT/conv.) increases rapidly until about 8 mm and then stabilizes beyond. Conclusion: A substantial enhancement in the dose sculpting capacity has been demonstrated for the novel DMBT tandem applicator. While

  14. SU-G-201-11: Exploring the Upper Limits of Dose Sculpting Capacity of the Novel Direction Modulated Brachytherapy (DMBT) Tandem Applicator

    Energy Technology Data Exchange (ETDEWEB)

    Han, D [University of California San Francisco, San Francisco, CA (United States); Department of Medical Physics, Sunnybrook Health Sciences Centre, University of Toronto, Toronto, ON (Canada); Safigholi, H; Soliman, A [Department of Medical Physics, Sunnybrook Health Sciences Centre, University of Toronto, Toronto, ON (Canada); Song, W [Department of Medical Physics, Sunnybrook Health Sciences Centre, University of Toronto, Toronto, ON (Canada); University of Toronto, Toronto, ON (Canada)

    2016-06-15

    Purpose: To explore and quantify the upper limits in dose sculpting capacity of the novel direction modulated brachytherapy (DMBT) tandem applicator compared with conventional tandem design for {sup 192}Ir-based HDR planning. Methods: The proposed DMBT tandem applicator is designed for image-guided adaptive brachytherapy (IGABT), especially MRI, of cervical cancer. It has 6 peripheral holes of 1.3-mm width, grooved along a 5.4-mm diameter nonmagnetic tungsten alloy rod of density 18.0 g/cc, capable of generating directional dose profiles – leading to enhanced dose sculpting capacity through inverse planning. The external dimensions are identical to that of conventional tandem design to ensure clinical compatibility. To explore the expansive dose sculpting capacity, we constructed a hypothetical circular target with 20-mm radius and positioned the DMBT and conventional tandems at the center. We then incrementally shifted the positions laterally away from the center of up to 15 mm, at 1-mm steps. The in-house coded gradient projection-based inverse planning system was then used to generate inverse optimized plans ensuring identical V100=100% coverage. Conformity index (CI) was calculated for all plans. Results: Overall, the DMBT tandem generates more conformal dose distributions than conventional tandem for all lateral positional shifts of 0-15 mm (CI=0.91–0.52 and 0.99–0.34, respectively), with an exception at the central position due to the ideal circular dose distribution, generated by the {sup 192}Ir, fitting tightly around the circular target (CI = 0.91 and 0.99, respectively). The DMBT tandem is able to generate dose conformity of CI>0.8 at up to 6-mm positional shift while the conventional tandem violates this past 2-mm shift. Also, the CI ratio (=DMBT/conv.) increases rapidly until about 8 mm and then stabilizes beyond. Conclusion: A substantial enhancement in the dose sculpting capacity has been demonstrated for the novel DMBT tandem applicator. While

  15. SU-F-T-30: Comprehensive Dosimetric Characterization of the Novel Direction Modulation Brachytherapy (DMBT) Tandem Applicator Using Monte Carlo Simulations

    Energy Technology Data Exchange (ETDEWEB)

    Safigholi, H; Mashouf, S; Soliman, Abraam; Owrangi, A; Song, W Y [Deprtment of Medical Physics, Sunnybrook Health Sciences Centre, University of Toronto, Toronto, ON (Canada); Han, D [Deprtment of Medical Physics, Sunnybrook Health Sciences Centre, University of Toronto, Toronto, ON (Canada); Department of Radiation Oncology, University of California San Francisco, San Francisco, CA (United States)

    2016-06-15

    Purpose: To characterize the dosimetric properties/distributions of the novel proposed direction modulated brachytherapy (DMBT) tandem applicator in combination with 192Ir HDR source, and compare against conventional tandem design, using Monte Carlo simulations. Methods: The proposed DMBT tandem applicator is designed for image-guided adaptive brachytherapy, especially MRI, of cervical cancer. It has 6 peripheral holes of 1.3-mm width, grooved along a 5.4-mm diameter nonmagnetic tungsten alloy rod of density 18.0 g/cc, capable of generating directional dose profiles – leading to enhanced dose sculpting capacity through inverse planning. In-water dosimetric parameters for the DMBT and conventional tandems have been calculated for various radial distances away and around the tandems. For the DMBT tandem, the cumulative dose from the 192Ir source occupying 1) one and 2) all six holes in equal dwell times was calculated and normalized to match the dose rate of the open source (in conventional tandem) at 1 cm from the center. This is done to compare and contrast the characteristic dose distributions to that of the isotropic TG43-based 192Ir source. Results: All dose rates were normalized at 1-cm radius from the center of the applicators, containing source(s). The normalized dose rates at 0.5, 3.0, and 5.0-cm radiuses were then 388, 11.3, and 4.1% for conventional tandem, 657, 8.1, and 2.7% for DMBT tandem with the source in one hole at front entrance, and 436, 10.9, and 3.8% for DMBT tandem with the source in all six holes. For the DMBT tandem case with the source in one hole, the backside transmissions were 47, 2.4, and 0.9%, respectively. Conclusion: The DMBT tandem is able to generate closely similar dosimetric characteristics as that of the single-channel conventional tandem if needed (with the source occupying all six holes), at the same time, generate directional radiation profile(s) for favorably enabling 3D dose sculpting capability.

  16. Brachytherapy of endometrial cancers

    International Nuclear Information System (INIS)

    Peiffert, D.; Hoffstetter, S.; Charra-Brunaud, C.

    2003-01-01

    Endometrial adenocarcinomas rank third as tumoral sites en France. The tumors are confined to the uterus in 80% of the cases. Brachytherapy has a large place in the therapeutic strategy. The gold standard treatment remains extra-fascial hysterectomy with bilateral annexiectomy and bilateral internal iliac lymph node dissection. However, after surgery alone, the rate of locoregional relapses reaches 4-20%, which is reduced to 0-5% after postoperative brachytherapy of the vaginal cuff. This postoperative brachytherapy is delivered as outpatients treatment, by 3 or 4 fractions, at high dose rate. The utero-vaginal preoperative brachytherapy remains well adapted to the tumors which involve the uterine cervix. Patients presenting a localized tumor but not operable for general reasons (< 10%) can be treated with success by exclusive irradiation, which associates a pelvic irradiation followed by an utero-vaginal brachytherapy. A high local control of about 80-90% is obtained, a little lower than surgery, with a higher risk of late complications. Last but not least, local relapses in the vaginal cuff, or in the perimeatic area, can be treated by interstitial salvage brachytherapy, associated if possible with external beam irradiation. The local control is reached in half of the patients, but metastatic dissemination is frequent. We conclude that brachytherapy has a major role in the treatment of endometrial adenocarcinomas, in combination with surgery, or with external beam irradiation for not operable patients or in case of local relapses. It should use new technologies now available including computerized after-loaders and 3D dose calculation. (authors)

  17. High dose rate brachytherapy for superficial cancer of the esophagus

    International Nuclear Information System (INIS)

    Maingon, Philippe; D'Hombres, Anne; Truc, Gilles; Barillot, Isabelle; Michiels, Christophe; Bedenne, Laurent; Horiot, Jean Claude

    2000-01-01

    Purpose: We analyzed our experience with external radiotherapy, combined modality treatment, or HDR brachytherapy alone to limited esophageal cancers. Methods and Materials: From 1991 to 1996, 25 patients with limited superficial esophagus carcinomas were treated by high dose rate brachytherapy. The mean age was 63 years (43-86 years). Five patients showed superficial local recurrence after external radiotherapy. Eleven patients without invasion of the basal membrane were staged as Tis. Fourteen patients with tumors involving the submucosa without spreading to the muscle were staged as T1. Treatment consisted of HDR brachytherapy alone in 13 patients, external radiotherapy and brachytherapy in 8 cases, and concomitant chemo- and radiotherapy in 4 cases. External beam radiation was administered to a total dose of 50 Gy using 2 Gy daily fractions in 5 weeks. In cases of HDR brachytherapy alone (13 patients), 6 applications were performed once a week. Results: The mean follow-up is 31 months (range 24-96 months). Twelve patients received 2 applications and 13 patients received 6 applications. Twelve patients experienced a failure (48%), 11/12 located in the esophagus, all of them in the treated volume. One patient presented an isolated distant metastasis. In the patients treated for superficial recurrence, 4/5 were locally controlled (80%) by brachytherapy alone. After brachytherapy alone, 8/13 patients were controlled (61%). The mean disease-free survival is 14 months (1-36 months). Overall survival is 76% at 1 year, 37% at 2 years, and 14% at 3 years. Overall survival for Tis patients is 24% vs. 20% for T1 (p 0.83). Overall survival for patients treated by HDR brachytherapy alone is 43%. One patient presented with a fistula with local failure after external radiotherapy and brachytherapy. Four stenosis were registered, two were diagnosed on barium swallowing without symptoms, and two required dilatations. Conclusion: High dose rate brachytherapy permits the treating

  18. A dose planning study on applicator guided stereotactic IMRT boost in combination with 3D MRI based brachytherapy in locally advanced cervical cancer

    International Nuclear Information System (INIS)

    Assenholt, Marianne S.; Petersen, Joergen B.; Nielsen, Soeren K.; Lindegaard, Jacob C.; Tanderup, Kari

    2008-01-01

    Purpose. Locally advanced cervical cancer is usually treated with external beam radiotherapy followed by brachytherapy (BT). However, if response or tumour topography is unfavourable it may be difficult to reach a sufficient BT dose. The purpose of this study was to explore whether an applicator guided stereotactic IMRT boost could be combined with brachytherapy to improve dose volume parameters. Material and methods. Dose plans of 6 patients with HR CTV volumes of 31-100cc at the time of BT were analysed. MRI was performed with a combined intracavitary (IC)-interstitial (IS) ring applicator in situ. A radiotherapy schedule consisting of 45Gy (1.8Gyx25) IMRT followed by boost of 28Gy (7Gyx4fx) was modelled. Four different boost techniques were evaluated: IC-BT, IC/IS-BT, IC-BT+IMRT and IMRT. Dose plans were optimised for maximal tumour dose (D90) and coverage (V85Gy) while respecting DVH constraints in organs at risk: D2cc <75Gy in rectum and sigmoid and <90Gy in bladder (EQD2). In combined BT+IMRT dose plans, the IMRT plan was optimised on top of the BT dose distribution. Volumes irradiated to more than 60 Gy EQD2 (V60Gy) were evaluated. Results. Median dose coverage in IC plans was 74% [66-93%]. By using IC/IS or IC-BT+IMRT boost, the median coverage was improved to 95% [78-99%], and to 96% [69-99%] respectively. For IMRT alone, a median coverage of 98% [90-100%] was achieved, but V60Gy volumes were significantly increased by a median factor of 2.0 [1.4-2.3] as compared to IC/IS. It depended on the individual tumour topography whether IC/IS-BT or IC-BT+IMRT boost was the most favourable technique. Conclusion. It is technically possible to create dose plans that combine image guided BT and IMRT. In this study the dose coverage could be significantly increased by adding IS-BT or IMRT boost to the intracavitary dose. Using IMRT alone for boost cannot be advocated since this results in a significant increase of the volume irradiated to 60Gy

  19. SU-F-T-38: How Much Dose Is Given in MR Guided Cervical Cancer Brachytherapy with the Ring and Tandem Applicators?

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, H [Department of Radiation Oncology, Northwestern University Feinberg School of Medicine, Northwestern Memorial Hospital, Chicago, IL (United States)

    2016-06-15

    Purpose: To evaluate the dosimetric metrics of HDR Ring and Tandem applicator Brachytherapy for primary cervical cancers. Methods: The dosimetric metrics of high-risk clinical target volumes (HDR-CTV) of 12 patients (in total 60 fractions/plans) treated with the HDR ring and tandem applicators were retrospectively analyzed. Ring diameter is from 2.6 to 3.4 cm, tandem length is from 4 to 6 cm, and the angle is either 45 or 60 degrees. The first fraction plan was MR guided, the MR images were then used as a reference for contouring the HR-CTV in CT images of following 4 fractions. The nominal prescription dose was between 5.2 and 5.8 Gy at the point A. The plans were adjusted to cover at least 90% of the HR-CTV by 90% of the prescription dose and to reduce the doses to the bladder, rectum and bowel-bag. Minimum target dose of D100 and D90 were converted into the biologically equivalent EBRT dose D90-iso and D100-iso (using α/β=10 Gy, 2 Gy/fx). Equivalent uniform doses (EUD) based on the average cancer killing across the target volume were calculated by the modified linear quadratic model (MLQ) from the differential dose volume histogram (DVH) tables. Results: The average D90iso of all plans is 8.1 Gy (ranging from 6.2 to 15 Gy, median 7.8 Gy); the average D100iso is just 4.1 Gy (ranging from 1.8 to 7.8 Gy; median 3.9 Gy). The average EUD is 7.0 Gy (ranging from 6.1 to 9.6 Gy, median 6.9 Gy), which is 87% of the D90iso, and 170% of the D100iso. Conclusion: The EUDs is smaller than D90iso but greater than D100iso. Because the EUD takes into account the intensive cancer cell killing in the high dose zone of HR-CTV, MLQ calculated EUD apparently is more relevant than D90 and D100 to describe the HDR brachytherapy treatment quality.

  20. Simulation of the shielding effects of an applicator on the AAPM TG-43 parameters of CS-137 Selectron LDR brachytherapy sources

    International Nuclear Information System (INIS)

    Sina, S.; Faghihi, R.; Meigooni, A. S.; Mehdizadeh, S.; Zehtabian, M.; Mosleh-Shirazi, M. A.

    2009-01-01

    The dose rate distribution delivered by a low dose rate 137 Cs pellet source, a spherical source used within the source trains Selectron gynecological brachytherapy system, was investigated using the MCNP4C Monte Carlo code. Materials and Methods: The calculations were performed in both water and Plexiglas and the absolute dose rate distribution for a single pellet source and the AAPM TG-43 parameters were computed. A spherical phantom with dimensions large enough (60 cm) was used to provide full scattering conditions. In order to score dose at different distances from the source centre, this sphere was divided into a set of 600 concentric spherical shells of 0.05 cm thickness. The calculations were performed up to a distance of 10 cm from the source centre. To calculate the effect of the applicator and dummy pellets on dose rate constant and radial dose function, a single pellet source was simulated inside the vaginal applicator, and spherical tally cells with radius of 0.05 cm were used in the simulations. The F6 tally was used to score the absolute dose rate at a given point in the phantom. Results: The dose rate constant for a single active pellet was found to be 1.102±0.007 cGyh -1 U -1 , and the dose rate constant for an active pellet inside the applicator was 1.095±0.009 cGyh -1 U -l . The tabulated data and 5th order polynomial fit coefficients for the radial dose function along with the dose rate constant are provided for both cases. The effect of applicator and dummy pellets on anisotropy function of the source was also investigated. Conclusion: The error resulting from ignoring the applicator was reduced using the data of a single pellet. The results indicate that F(r, θ) decreases towards the applicator.

  1. SU-G-TeP2-07: Dosimetric Characterization of a New HDR Multi-Channel Esophageal Applicator for Brachytherapy

    Energy Technology Data Exchange (ETDEWEB)

    Zhao, A; Gao, S; Greskovich, J; Wilkinson, D [Cleveland Clinic, Cleveland, OH (United States); Diener, T [Cleveland State University, Cleveland, OH (United States)

    2016-06-15

    Purpose: To characterize the dose distribution of a new multi-channel esophageal applicator for brachytherapy HDR treatment, and particularly the effect of the presence of air or water in the applicator’s expansion balloon. Methods: A new multi-channel (6) inflatable applicator for esophageal HDR has been developed in house and tested in a simple water phantom. CT image sets were obtained under several balloon expansions (80ml of air, 50 cc of water), and channel loadings and used with the Oncentra (Elekta) planning system based on TG43 formalism. 400 cGy was prescribed to a plane 1cm away from the applicator. Planar dose distributions were measured for that plane and one next to the applicator using Gafchromic EBT3 film and scanned by a Vidar VXR-12 film digitizer. Film and TPS generated dose distributions of film were sent to OmniPro I’mRT (iba DOSIMETRY) for analysis. 2D dose profiles in both X and Y directions were compared and gamma analysis performed. Results: Film dose measurement of the air-inflated applicator is lower than the TPS calculated dose by as much as 60%. Only 80.8% of the pixels passed the gamma criteria (3%/3mm). For the water-inflated applicator, the measured film dose is fairly close to the TPS calculated dose (typically within <3%). 99.84% of the pixels passed the gamma criteria (3%/3mm). Conclusion: TG43 based calculations worked well when water was used in the expansion balloon. However, when air is present in that balloon, the neglect of heterogeneity corrections in the TG43 calculation results in large differences between calculated and measured doses. This could result in severe underdosing when used in a patient. This study illustrates the need for a TPS with an advanced algorithm which can account for heterogeneity. Supported by Innovations Department, Cleveland Clinic.

  2. Production of 3D-shaped graphene via transfer printing

    International Nuclear Information System (INIS)

    Winters, Sinead; Nolan, Hugo; Duesberg, Georg S.; Hallam, Toby

    2012-01-01

    We present the fabrication of three-dimensional graphene structures supported by a polymer scaffold. The structures are fabricated using transfer printing. The structures could have potential applications in electronics, sensing and electrochemical electrodes. Electrochemical measurements confirm an increase in surface area due to the folding of the graphene over the polymer scaffolding. Further, the production method opens the possibility for strain engineering in graphene, opening a wide range of potential novel effects in the physical and chemical properties of graphene. (Copyright copyright 2012 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  3. Stress analysis of the conceptual design configurations of constant tension D-shaped superconducting toroidal field coils for TNS

    International Nuclear Information System (INIS)

    Fernades, R.; Smith, R.A.

    1977-01-01

    Conceptual design configurations of D-shaped toroidal field coils applicable to the TNS program are studied under the action of the toroidal field loading condition and the vertical field loading condition, but not the fault condition. Although the analysis is specific to an 8 Tesla design using a niobium titanium superconductor, the results can be extended to a coil with a different conductor material and subjected to a field of different magnitude provided the condition of linear elasticity is not violated. The analysis technique used is the finite element method, with three dimensional finite elements defined in the ANSYS computer code, and supplemented by closed form analytical solutions

  4. Comparison of different photoresist buffer layers in SPR sensors based on D-shaped POF and gold film

    Science.gov (United States)

    Cennamo, Nunzio; Pesavento, Maria; De Maria, Letizia; Galatus, Ramona; Mattiello, Francesco; Zeni, Luigi

    2017-04-01

    A comparative analysis of two optical fiber sensing platforms is presented. The sensors are based on surface plasmon resonance (SPR) in a D-shaped plastic optical fiber (POF) with a photoresist buffer layer between the exposed POF core and the thin gold film. We show how the sensor's performances change when the photoresist layer changes. The photoresist layers proposed in this analysis are SU-8 3005 and S1813. The experimental results are congruent with the numerical studies and it is instrumental for chemical and bio-chemical applications. Usually, the photoresist layer is required in order to increase the performance of the SPR-POF sensor.

  5. Review of advanced catheter technologies in radiation oncology brachytherapy procedures

    OpenAIRE

    Zhou J; Zamdborg L; Sebastian E

    2015-01-01

    Jun Zhou,1,2 Leonid Zamdborg,1 Evelyn Sebastian1 1Department of Radiation Oncology, Beaumont Health System, 2Oakland University William Beaumont School of Medicine, Royal Oak, MI, USA Abstract: The development of new catheter and applicator technologies in recent years has significantly improved treatment accuracy, efficiency, and outcomes in brachytherapy. In this paper, we review these advances, focusing on the performance of catheter imaging and reconstruction techniques in brachytherapy ...

  6. Image-robot coupling for the prostate brachytherapy

    International Nuclear Information System (INIS)

    Coelen, V.; Lartigau, E.; Merzouki, R.

    2009-01-01

    The results allows to contemplate a robot use in the prostate brachytherapy but equally in other applications such prostate biopsy. The tests to come are going to be directed towards on the use of a prostate phantom in order to calibrate the ultrasonography. thereafter, we contemplate the conception of an intelligent gripping system placed on the robot arm and allowing a good control in closed loop of the brachytherapy needle placement and allowing the setting up of an online monitoring. (N.C.)

  7. SU-G-201-02: Application of RayStretch in Clinical Cases: A Calculation for Heterogeneity Corrections in LDR Permanent I-125 Prostate Brachytherapy

    Energy Technology Data Exchange (ETDEWEB)

    Hueso-Gonzalez, F [Helmholtz-Zentrum Dresden-Rossendorf, Institute of Radiooncology, Dresden (Germany); Vijande, J [University of Valencia, Burjassot and IFIC (CSIC-UV) (Spain); Ballester, F [University of Valencia, Burjassot (Spain); Perez-Calatayud, J [Hospital Clinica Benidorm, Benidorm, and Hospital Universitari i Politecnic La Fe, Valencia (Spain); Siebert, F [Clinic of Radiotherapy (Radiooncology), Kiel (Germany)

    2016-06-15

    Purpose: Tissue heterogeneities and calcifications have significant impact on the dosimetry of low energy brachytherapy (BT). RayStretch is an analytical algorithm developed in our institution to incorporate heterogeneity corrections in LDR prostate brachytherapy. The aim of this work is to study its application in clinical cases by comparing its predictions with the results obtained with TG-43 and Monte Carlo (MC) simulations. Methods: A clinical implant (71 I-125 seeds, 15 needles) from a real patient was considered. On this patient, different volumes with calcifications were considered. Its properties were evaluated in three ways by i) the Treatment planning system (TPS) (TG-43), ii) a MC study using the Penelope2009 code, and iii) RayStretch. To analyse the performance of RayStretch, calcifications located in the prostate lobules covering 11% of the total prostate volume and larger calcifications located in the lobules and underneath the urethra for a total occupied volume of 30% were considered. Three mass densities (1.05, 1.20, and 1.35 g/cm3) were explored for the calcifications. Therefore, 6 different scenarios ranging from small low density calcifications to large high density ones have been discussed. Results: DVH and D90 results given by RayStretch agree within 1% with the full MC simulations. Although no effort has been done to improve RayStretch numerical performance, its present implementation is able to evaluate a clinical implant in a few seconds to the same level of accuracy as a detailed MC calculation. Conclusion: RayStretch is a robust method for heterogeneity corrections in prostate BT supported on TG-43 data. Its compatibility with commercial TPSs and its high calculation speed makes it feasible for use in clinical settings for improving treatment quality. It will allow in a second phase of this project, its use during intraoperative ultrasound planning. This study was partly supported by a fellowship grant from the Spanish Ministry of

  8. Reconstructing the Curve-Skeletons of 3D Shapes Using the Visual Hull.

    Science.gov (United States)

    Livesu, Marco; Guggeri, Fabio; Scateni, Riccardo

    2012-11-01

    Curve-skeletons are the most important descriptors for shapes, capable of capturing in a synthetic manner the most relevant features. They are useful for many different applications: from shape matching and retrieval, to medical imaging, to animation. This has led, over the years, to the development of several different techniques for extraction, each trying to comply with specific goals. We propose a novel technique which stems from the intuition of reproducing what a human being does to deduce the shape of an object holding it in his or her hand and rotating. To accomplish this, we use the formal definitions of epipolar geometry and visual hull. We show how it is possible to infer the curve-skeleton of a broad class of 3D shapes, along with an estimation of the radii of the maximal inscribed balls, by gathering information about the medial axes of their projections on the image planes of the stereographic vision. It is definitely worth to point out that our method works indifferently on (even unoriented) polygonal meshes, voxel models, and point clouds. Moreover, it is insensitive to noise, pose-invariant, resolution-invariant, and robust when applied to incomplete data sets.

  9. Reducing the pressure drag of a D-shaped bluff body using linear feedback control

    Science.gov (United States)

    Dalla Longa, L.; Morgans, A. S.; Dahan, J. A.

    2017-12-01

    The pressure drag of blunt bluff bodies is highly relevant in many practical applications, including to the aerodynamic drag of road vehicles. This paper presents theory revealing that a mean drag reduction can be achieved by manipulating wake flow fluctuations. A linear feedback control strategy then exploits this idea, targeting attenuation of the spatially integrated base (back face) pressure fluctuations. Large-eddy simulations of the flow over a D-shaped blunt bluff body are used as a test-bed for this control strategy. The flow response to synthetic jet actuation is characterised using system identification, and controller design is via shaping of the frequency response to achieve fluctuation attenuation. The designed controller successfully attenuates integrated base pressure fluctuations, increasing the time-averaged pressure on the body base by 38%. The effect on the flow field is to push the roll-up of vortices further downstream and increase the extent of the recirculation bubble. This control approach uses only body-mounted sensing/actuation and input-output model identification, meaning that it could be applied experimentally.

  10. Positional variability of a tandem applicator system in HDR brachytherapy for primary treatment of cervix cancer. Analysis of the anatomic pelvic position and comparison of the applicator positions during five insertions

    International Nuclear Information System (INIS)

    Wulf, J.; Popp, K.; Oppitz, U.; Baier, K.; Flentje, M.

    2004-01-01

    Purpose: evaluation of the inter- and intraindividual applicator variability of multiple high-dose-rate (HDR) brachytherapy applications for primary treatment of cancer of the uterine cervix. Material and methods: retrospective analysis of 460 pairs of orthogonal X-ray films for conventional treatment in 92 patients with five intrauterine applications using an HDR tandem applicator. Measurement of the position of the applicator origin relative to a bony reference system in three dimensions. Evaluation of the differences of the applicator position in all 460 applications (interindividual variability), of the five applications in a single patient (intraindividual variability) and of the intraindividual variability relative to the applicator position at the first application. Results: the position of the applicator origin in the pelvis ranged from 23 mm cranial and 55 mm caudal to the top of femoral heads, 23 mm right and 27 mm left to the pelvic midline, and 6-53 mm dorsal to the mid of the femoral heads. Standard deviation (SD) of interindividual applicator variability was 12.9 mm (minimum/maximum -55/+23 mm, mean -13.6 mm) in longitudinal, 5.1 mm (-27/+23 mm, mean 1.6 mm) in lateral, and 7.6 mm (6/53 mm, mean 26 mm) in anterior-posterior [AP] direction. SD of intraindividual variability was 5.5 mm (-21/+23 mm, mean 0 mm) in longitudinal, 2.5 mm (-17/+19 mm, mean 0 mm) in lateral, and 4.2 mm (-15/+18 mm, mean 0 mm) in AP direction compared to intraindividual variability relative to the first insertion with an SD of 8.9 mm (-23/+36 mm, mean 2.8 mm) in longitudinal, 4.0 mm (-11/+23 mm, mean 0 mm) in lateral, and 6.8 mm (-27/+17 mm, mean -0.8 mm) in AP direction. Conclusion: intraindividual applicator variability is significantly smaller than interindividual variability. Applicator-related procedures such as midline shielding or dose matching of tele- and brachytherapy should be performed with information on at least one individual applicator position. (orig.)

  11. Positional variability of a tandem applicator system in HDR brachytherapy for primary treatment of cervix cancer. Analysis of the anatomic pelvic position and comparison of the applicator positions during five insertions

    Energy Technology Data Exchange (ETDEWEB)

    Wulf, J.; Popp, K.; Oppitz, U.; Baier, K.; Flentje, M. [Dept. of Radiotherapy, Univ. of Wuerzburg (Germany)

    2004-04-01

    Purpose: evaluation of the inter- and intraindividual applicator variability of multiple high-dose-rate (HDR) brachytherapy applications for primary treatment of cancer of the uterine cervix. Material and methods: retrospective analysis of 460 pairs of orthogonal X-ray films for conventional treatment in 92 patients with five intrauterine applications using an HDR tandem applicator. Measurement of the position of the applicator origin relative to a bony reference system in three dimensions. Evaluation of the differences of the applicator position in all 460 applications (interindividual variability), of the five applications in a single patient (intraindividual variability) and of the intraindividual variability relative to the applicator position at the first application. Results: the position of the applicator origin in the pelvis ranged from 23 mm cranial and 55 mm caudal to the top of femoral heads, 23 mm right and 27 mm left to the pelvic midline, and 6-53 mm dorsal to the mid of the femoral heads. Standard deviation (SD) of interindividual applicator variability was 12.9 mm (minimum/maximum -55/+23 mm, mean -13.6 mm) in longitudinal, 5.1 mm (-27/+23 mm, mean 1.6 mm) in lateral, and 7.6 mm (6/53 mm, mean 26 mm) in anterior-posterior [AP] direction. SD of intraindividual variability was 5.5 mm (-21/+23 mm, mean 0 mm) in longitudinal, 2.5 mm (-17/+19 mm, mean 0 mm) in lateral, and 4.2 mm (-15/+18 mm, mean 0 mm) in AP direction compared to intraindividual variability relative to the first insertion with an SD of 8.9 mm (-23/+36 mm, mean 2.8 mm) in longitudinal, 4.0 mm (-11/+23 mm, mean 0 mm) in lateral, and 6.8 mm (-27/+17 mm, mean -0.8 mm) in AP direction. Conclusion: intraindividual applicator variability is significantly smaller than interindividual variability. Applicator-related procedures such as midline shielding or dose matching of tele- and brachytherapy should be performed with information on at least one individual applicator position. (orig.)

  12. Direct reconstruction and associated uncertainties of 192Ir source dwell positions in ring applicators using gafchromic film in the treatment planning of HDR brachytherapy cervix patients

    Science.gov (United States)

    Awunor, O. A.; Dixon, B.; Walker, C.

    2013-05-01

    This paper details a practical method for the direct reconstruction of high dose rate 192Ir source dwell positions in ring applicators using gafchromic film in the treatment planning of brachytherapy cervix patients. It also details the uncertainties associated with such a process. Eight Nucletron interstitial ring applicators—Ø26 mm (×4), Ø30 mm (×3) and Ø34 mm (×1), and one 60 mm intrauterine tube were used in this study. RTQA2 and XRQA2 gafchromic films were irradiated at pre-programmed dwell positions with three successive 192Ir sources and used to derive the coordinates of the source dwell positions. The source was observed to deviate significantly from its expected position by up to 6.1 mm in all ring sizes. Significant inter applicator differences of up to 2.6 mm were observed between a subset of ring applicators. Also, the measured data were observed to differ significantly from commercially available source path models provided by Nucletron with differences of up to 3.7 mm across all ring applicator sizes. The total expanded uncertainty (k = 2) averaged over all measured dwell positions in the rings was observed to be 1.1 ± 0.1 mm (Ø26 mm and Ø30 mm rings) and 1.0 ± 0.3 mm (Ø34 mm ring) respectively, and when transferred to the treatment planning system, equated to maximum %dose changes of 1.9%, 13.2% and 1.5% at regions representative of the parametrium, lateral fornix and organs at risk respectively.

  13. Image guided, adaptive, accelerated, high dose brachytherapy as model for advanced small volume radiotherapy

    International Nuclear Information System (INIS)

    Haie-Meder, Christine; Siebert, Frank-Andre; Poetter, Richard

    2011-01-01

    Brachytherapy has consistently provided a very conformal radiation therapy modality. Over the last two decades this has been associated with significant improvements in imaging for brachytherapy applications (prostate, gynecology), resulting in many positive advances in treatment planning, application techniques and clinical outcome. This is emphasized by the increased use of brachytherapy in Europe with gynecology as continuous basis and prostate and breast as more recently growing fields. Image guidance enables exact knowledge of the applicator together with improved visualization of tumor and target volumes as well as of organs at risk providing the basis for very individualized 3D and 4D treatment planning. In this commentary the most important recent developments in prostate, gynecological and breast brachytherapy are reviewed, with a focus on European recent and current research aiming at the definition of areas for important future research. Moreover the positive impact of GEC-ESTRO recommendations and the highlights of brachytherapy physics are discussed what altogether presents a full overview of modern image guided brachytherapy. An overview is finally provided on past and current international brachytherapy publications focusing on 'Radiotherapy and Oncology'. These data show tremendous increase in almost all research areas over the last three decades strongly influenced recently by translational research in regard to imaging and technology. In order to provide high level clinical evidence for future brachytherapy practice the strong need for comprehensive prospective clinical research addressing brachytherapy issues is high-lighted.

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

    International Nuclear Information System (INIS)

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

    2006-01-01

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

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

    Science.gov (United States)

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

    2006-07-21

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

  16. Dosimetric and radiobiological comparison of TG-43 and Monte Carlo calculations in 192Ir breast brachytherapy applications.

    Science.gov (United States)

    Peppa, V; Pappas, E P; Karaiskos, P; Major, T; Polgár, C; Papagiannis, P

    2016-10-01

    To investigate the clinical significance of introducing model based dose calculation algorithms (MBDCAs) as an alternative to TG-43 in 192 Ir interstitial breast brachytherapy. A 57 patient cohort was used in a retrospective comparison between TG-43 based dosimetry data exported from a treatment planning system and Monte Carlo (MC) dosimetry performed using MCNP v. 6.1 with plan and anatomy information in DICOM-RT format. Comparison was performed for the target, ipsilateral lung, heart, skin, breast and ribs, using dose distributions, dose-volume histograms (DVH) and plan quality indices clinically used for plan evaluation, as well as radiobiological parameters. TG-43 overestimation of target DVH parameters is statistically significant but small (less than 2% for the target coverage indices and 4% for homogeneity indices, on average). Significant dose differences (>5%) were observed close to the skin and at relatively large distances from the implant leading to a TG-43 dose overestimation for the organs at risk. These differences correspond to low dose regions (<50% of the prescribed dose), being less than 2% of the prescribed dose. Detected dosimetric differences did not induce clinically significant differences in calculated tumor control probabilities (mean absolute difference <0.2%) and normal tissue complication probabilities. While TG-43 shows a statistically significant overestimation of most indices used for plan evaluation, differences are small and therefore not clinically significant. Improved MBDCA dosimetry could be important for re-irradiation, technique inter-comparison and/or the assessment of secondary cancer induction risk, where accurate dosimetry in the whole patient anatomy is of the essence. Copyright © 2016 Associazione Italiana di Fisica Medica. Published by Elsevier Ltd. All rights reserved.

  17. 3D shape recovery from image focus using gray level co-occurrence matrix

    Science.gov (United States)

    Mahmood, Fahad; Munir, Umair; Mehmood, Fahad; Iqbal, Javaid

    2018-04-01

    Recovering a precise and accurate 3-D shape of the target object utilizing robust 3-D shape recovery algorithm is an ultimate objective of computer vision community. Focus measure algorithm plays an important role in this architecture which convert the color values of each pixel of the acquired 2-D image dataset into corresponding focus values. After convolving the focus measure filter with the input 2-D image dataset, a 3-D shape recovery approach is applied which will recover the depth map. In this document, we are concerned with proposing Gray Level Co-occurrence Matrix along with its statistical features for computing the focus information of the image dataset. The Gray Level Co-occurrence Matrix quantifies the texture present in the image using statistical features and then applies joint probability distributive function of the gray level pairs of the input image. Finally, we quantify the focus value of the input image using Gaussian Mixture Model. Due to its little computational complexity, sharp focus measure curve, robust to random noise sources and accuracy, it is considered as superior alternative to most of recently proposed 3-D shape recovery approaches. This algorithm is deeply investigated on real image sequences and synthetic image dataset. The efficiency of the proposed scheme is also compared with the state of art 3-D shape recovery approaches. Finally, by means of two global statistical measures, root mean square error and correlation, we claim that this approach -in spite of simplicity generates accurate results.

  18. Role of brachytherapy in the treatment of localized prostate cancer

    Directory of Open Access Journals (Sweden)

    A. D. Kaprin

    2015-01-01

    Full Text Available The review is devoted to application of brachytherapy for treating the localized prostate cancer (PC. Statistics for incidence and detectability of this pathology and its dynamics for recent years are represented. Brief analysis of other methods which are conveniently used for treatment of PC, such as radical prostatectomy and external-beam radiotherapy, was performed. Advantages and disadvantages of these methods have been discussed. Brief history about the development of brachytherapy from first experience to wide-spread use in clinical practice is reported. The detailed review of series of large trials from Russia and other countries for efficiency and safety of brachytherapy in patients with prostate cancer for recent 15 years is also represented. Two types of brachytherapy in current clinical oncology i.e. low-dose technique with permanent implantation of microsources and high-dose temporary isotope implantation, specifics of its application in different groups of patients have been described. The procedure of brachytherapy and its three main steps i.e. planning, implantation and control assessment after implantation have been characterized in details. The conclusion about benefits of using of brachytherapy in the treatment of prostate cancer as minimally invasive and efficient method was made. 

  19. Afterloading techniques in brachytherapy

    International Nuclear Information System (INIS)

    Kirsch, M.; Orban, R.; Lorenz, B.

    1981-01-01

    The advantages of applying modern afterloading methods in brachytherapie of malignant diseases are outlined. They include, among other things, a considerable reduction in radiation exposure to staff involved. Furthermore, the radiation protection requirements imposed by the licensing authority on the construction, equipment and operation of remote controlled afterloading installations with gamma sources of up to 4 TBq (108 Ci) have been compiled. (author)

  20. Brachytherapy for oral cancer

    International Nuclear Information System (INIS)

    Monzen, Yoshio; Ajimu, Akira; Morikawa, Minoru; Hayashi, Nobuyuki; Yoshida, Shintarou; Ashizawa, Kazuto; Hayashi, Kuniaki; Ikenaga, Kouji; Sakamoto, Ichirou.

    1988-01-01

    13 cases with oral cancer were treated using brachytherapy at the Department of Radiology, Nagasaki University Hospital from September 1985 to February 1988. Among 11 cases of tongue cancer, T1 and T2 cases were well controlled by radiation therapy using 226 Ra needles. Cancer of oral floor and buccal mucosa were controlled by the use of 192 Au grains. (author)

  1. [Brachytherapy of brainstem tumors].

    Science.gov (United States)

    Julow, Jenö; Viola, Arpád; Major, Tibor; Valálik, István; Sági, Sarolta; Mangel, László; Kovács, Rita Beáta; Repa, Imre; Bajzik, Gábor; Németh, György

    2004-01-20

    The optimal therapy of brain stem tumours of different histopathology determines the expected length of survival. Authors report 125Iodine interstitial irradiation of brain stem tumours with stereotactic brachytherapy. Two patients having brain stem tumours were suffering from glioma or from metastases of a carcinoma. In Case 1 the tumour volume was 1.98 cm3 at the time of planning interstitial irradiation. The control MRI examination performed at 42 months post-op showed a postirradiation cyst size of 5.73 cm3 indicating 65.5% shrinkage. In Case 2 the shrinkage was more apparent as the tumour volume measured on the control MRI at 8 months post-op was only 0.16 cm3 indicating 97.4% shrinkage of the 6.05 cm3 target volume at the time of brachytherapy with the metastasis practically disappearing. Quick access to histopathological results of the stereotactic intraoperative biopsy made it possible to carry out the 125Iodine stereotactic brachytherapy immediately after the biopsy, resulting in less inconvenience for patients of a second possible intervention. The control MRI scans show significant shrinkage of tumours in both patients. The procedure can be performed as a biopsy. The CT and image fusion guided 125Iodine stereotactic brachytherapy can be well planned dosimetrically and is surgically precise.

  2. SU-F-19A-04: Dosimetric Evaluation of a Novel CT/MR Compatible Fletcher Applicator for Intracavitary Brachytherapy of the Cervix Uteri

    International Nuclear Information System (INIS)

    Gifford, K; Han, T; Mourtada, F; Eifel, P

    2014-01-01

    Purpose: To validate a Monte Carlo model and evaluate the dosimetric capabilities of a novel commercial CT/MR compatible Fletcher applicator for cervical cancer brachytherapy. Methods: MCNPX 2.7.0 was used to model the Fletcher CT/MR shielded applicator (FA) and 192Ir HDR source. Energy deposition was calculated with a track length estimator modified by an energy-dependent heating function. A high density polystyrene phantom was constructed with three film pockets for validation of the MCNPX model. Three planes of data were calculated with the MCNPX model corresponding to the three film planes in phantom. The planes were located 1 cm from the most anterior, posterior, and medial extents of the FA right ovoid. Unshielded distributions were calculated by modeling the shielded cells as air instead of the tungsten alloy. A third order polynomial fit to the OD to dose curve was used to convert OD of the three film planes to dose. Each film and MCNPX plane dose distribution was normalized to a point 2 cm from the center of the film plane and in a region of low dose gradient. MCNPX and film were overlaid and compared with a distance-to-agreement criterion of (±2%/±2mm). Shielded and unshielded distributions were overlaid and a percent shielded plot was created. Results: 85.2%, 97.1%, and 96.6% of the MCNPX points passed the (±2%/±2mm) criterion respectively for the anterior, lateral, and posterior film comparison planes. A majority of the points in the anterior plane that exceeded the DTA criterion were either along edges of where the film was cut or near the terminal edges of the film. The percent shielded matrices indicated that the maximum % shielding was 50%. Conclusion: These data confirm the validity of the FA Monte Carlo model. The FA ovoid can shield up to 50% of the dose in the anteroposterior direction

  3. SU-F-T-35: Optimization of Bladder and Rectal Doses Using a Multi-Lumen Intracavitary Applicator for Gynecological Brachytherapy

    Energy Technology Data Exchange (ETDEWEB)

    Laoui, S; Dietrich, S; Sehgal, V; Al-Ghazi, M [University of California, Irvine, Orange, CA (United States)

    2016-06-15

    Purpose: Radiation dose delivery for endometrial cancer using HDR techniques is limited by dose to bladder and rectum. A dosimetric study was performed using Varian Capri vaginal brachytherapy applicator to determine the optimal channel configuration which minimizes dose to bladder and rectum, while providing good target coverage. Methods: A total of 17 patients, 63 plans clinically delivered, and 252 simulated plans using Varian BrachyVision planning system were generated to investigate optimal channel configuration which results in minimum dose to bladder and rectum while providing adequate target coverage. The Capri applicator consists of 13 lumens arranged in two concentric rings, one central lumen and six lumens per ring. Manual dose shaping is invariably required to lower the dose to critical organs. Three-dimensional plans were simulated for 4 channel arrangements, all 13 channels, channel 12 o’clock (close to bladder) and 6 o’clock (close to rectum) deactivated, central channel deactivated, and central channel in addition to 12 o’clock and 6 o’clock deactivated. A relationship between V100, the volume that receives the prescribed dose, and the amount of curie-seconds required to deliver it, was established. Results: Using all 13 channels results in maximum dose to bladder and rectum. Deactivating central channel in addition to 12 o’clock and 6 o’clock resulted in minimizing bladder and rectum doses but compromised target coverage. The relationship between V100, the volume that receives the prescribed dose, and the curie seconds was found to be linear. Conclusion: Deactivating channels 12 o’clock and 6 o’clock was shown to be the optimal configuration leading to minimum dose to bladder and rectum without compromising target coverage. The linear relationship between V100 and the curie- seconds can be used as a verification parameter.

  4. Comparison of Intraoperatively Built Custom Linked Seeds Versus Loose Seed Gun Applicator Technique Using Real-Time Intraoperative Planning for Permanent Prostate Brachytherapy

    Energy Technology Data Exchange (ETDEWEB)

    Zauls, A. Jason; Ashenafi, Michael S. [Department of Radiation Oncology, Hollings Cancer Center, Medical University of South Carolina, Charleston, SC (United States); Onicescu, Georgiana [Department of Biostatistics and Epidemiology, Hollings Cancer Center, Medical University of South Carolina, Charleston, SC (United States); Clarke, Harry S. [Department of Urology, Hollings Cancer Center, Medical University of South Carolina, Charleston, SC (United States); Marshall, David T., E-mail: marshadt@musc.edu [Department of Radiation Oncology, Hollings Cancer Center, Medical University of South Carolina, Charleston, SC (United States)

    2011-11-15

    Purpose: To report our dosimetric results using a novel push-button seed delivery system that constructs custom links of seeds intraoperatively. Methods and Materials: From 2005 to 2007, 43 patients underwent implantation using a gun applicator (GA), and from 2007 to 2008, 48 patientsunderwent implantation with a novel technique allowing creation of intraoperatively built custom links of seeds (IBCL). Specific endpoint analyses were prostate D90% (pD90%), rV100% > 1.3 cc, and overall time under anesthesia. Results: Final analyses included 91 patients, 43 GA and 48 IBCL. Absolute change in pD90% ({Delta}pD90%) between intraoperative and postoperative plans was evaluated. Using GA method, the {Delta}pD90% was -8.1Gy and -12.8Gy for I-125 and Pd-103 implants, respectively. Similarly, the IBCL technique resulted in a {Delta}pD90% of -8.7Gy and -9.8Gy for I-125 and Pd-103 implants, respectively. No statistically significant difference in {Delta}pD90% was found comparing methods. The GA method had two intraoperative and 10 postoperative rV100% >1.3 cc. For IBCL, five intraoperative and eight postoperative plans had rV100% >1.3 cc. For GA, the mean time under anesthesia was 75 min and 87 min for Pd-103 and I-125 implants, respectively. For IBCL, the mean time was 86 and 98 min for Pd-103 and I-125. There was a statistical difference between the methods when comparing mean time under anesthesia. Conclusions: Dosimetrically relevant endpoints were equivalent between the two methods. Currently, time under anesthesia is longer using the IBCL technique but has decreased over time. IBCL is a straightforward brachytherapy technique that can be implemented into clinical practice as an alternative to gun applicators.

  5. SU-F-19A-04: Dosimetric Evaluation of a Novel CT/MR Compatible Fletcher Applicator for Intracavitary Brachytherapy of the Cervix Uteri

    Energy Technology Data Exchange (ETDEWEB)

    Gifford, K; Han, T [UT MD Anderson Cancer Center, Houston, TX (United States); Mourtada, F [Christiana Care Hospital, Newark, DE (United States); Eifel, P [The UT MD Anderson Cancer Center, Houston, TX (United States)

    2014-06-15

    Purpose: To validate a Monte Carlo model and evaluate the dosimetric capabilities of a novel commercial CT/MR compatible Fletcher applicator for cervical cancer brachytherapy. Methods: MCNPX 2.7.0 was used to model the Fletcher CT/MR shielded applicator (FA) and 192Ir HDR source. Energy deposition was calculated with a track length estimator modified by an energy-dependent heating function. A high density polystyrene phantom was constructed with three film pockets for validation of the MCNPX model. Three planes of data were calculated with the MCNPX model corresponding to the three film planes in phantom. The planes were located 1 cm from the most anterior, posterior, and medial extents of the FA right ovoid. Unshielded distributions were calculated by modeling the shielded cells as air instead of the tungsten alloy. A third order polynomial fit to the OD to dose curve was used to convert OD of the three film planes to dose. Each film and MCNPX plane dose distribution was normalized to a point 2 cm from the center of the film plane and in a region of low dose gradient. MCNPX and film were overlaid and compared with a distance-to-agreement criterion of (±2%/±2mm). Shielded and unshielded distributions were overlaid and a percent shielded plot was created. Results: 85.2%, 97.1%, and 96.6% of the MCNPX points passed the (±2%/±2mm) criterion respectively for the anterior, lateral, and posterior film comparison planes. A majority of the points in the anterior plane that exceeded the DTA criterion were either along edges of where the film was cut or near the terminal edges of the film. The percent shielded matrices indicated that the maximum % shielding was 50%. Conclusion: These data confirm the validity of the FA Monte Carlo model. The FA ovoid can shield up to 50% of the dose in the anteroposterior direction.

  6. Dosimetric evaluation of a combination of brachytherapy applicators for uterine cervix cancer with involvement of the distal vagina; Avaliacao dosimetrica de uma combinacao de aplicadores para braquiterapia de tumores do colo uterino com acometimento da porcao distal da vagina

    Energy Technology Data Exchange (ETDEWEB)

    Guimaraes, Roger Guilherme Rodrigues [Real e Benemerita Sociedade Portuguesa de Beneficencia, Sao Paulo, SP (Brazil). Servico de Radioterapia Estereotactica; Carvalho, Heloisa de Andrade; Stuart, Silvia Radwanski; Rubo, Rodrigo Augusto [Universidade de Sao Paulo (USP), SP (Brazil). Hospital das Clinicas. Servico de Radioterapia], e-mail: handrade@hcnet.usp.br; Seraide, Rodrigo Migotto [Centro de Oncologia Campinas, SP (Brazil)

    2009-07-15

    Objective: To evaluate an alternative brachytherapy technique for uterine cervix cancer involving the distal vagina, without increasing the risk of toxicity. Materials And Methods: Theoretical study comparing three different high-dose rate intracavitary brachytherapy applicators: intrauterine tandem and vaginal cylinder (TC); tandem/ring applicator combined with vaginal cylinder (TR+C); and a virtual applicator combining both the tandem/ring and vaginal cylinder in a single device (TRC). Prescribed doses were 7 Gy at point A, and 5 Gy on the surface or at a 5 mm depth of the vaginal mucosa. Doses delivered to the rectum, bladder and sigmoid colon were kept below the tolerance limits. Volumes covered by the isodoses, respectively, 50% (V50), 100% (V100), 150% (V150) and 200% (V200) were compared. Results: Both the combined TR+C and TRC presented a better dose distribution as compared with the TC applicator. The TR+C dose distribution was similar to the TRC dose, with V150 and V200 being about 50% higher for TR+C (within the cylinder). Conclusion: Combined TR+C in a two-time single application may represent an alternative therapy technique for patients affected by uterine cervix cancer involving the distal vagina. (author)

  7. SU-G-IeP1-09: MRI Evaluation of a Direction-Modulated Brachytherapy (DMBT) Tandem Applicator for Cervical Cancer On 3T

    Energy Technology Data Exchange (ETDEWEB)

    Soliman, A; Safigholi, H [Sunnybrook Research Institute, Toronto, ON (Canada); Sunnybrook Health Sciences Centre, Toronto, ON (Canada); Han, D [University of California San Francisco, San Francisco, CA (United States); Elzibak, A; Mashouf, S; Owrangi, A; Ravi, A [Sunnybrook Health Sciences Centre, Toronto, ON (Canada); University of Toronto, Toronto, ON (Canada); Song, W [Sunnybrook Research Institute, Toronto, ON (Canada); Sunnybrook Health Sciences Centre, Toronto, ON (Canada); University of Toronto, Toronto, ON (Canada)

    2016-06-15

    Purpose: To assess image quality and artifact extent of a novel direction modulated brachytherapy (DMBT) tandem applicator on a 3T MRI using various clinical imaging sequences. Methods: The tandem applicator is composed of a tungsten alloy with 6 peripheral grooves covered with a PEEK tip. An MR-compatible phantom with similar dimensions to the female pelvis was manufactured. To visually assess the spatial shift of the applicator’s tip, a mountable radial-fiducial with 4 plastic rods, each of 3mm diameter, was designed to tightly fit on the applicator. The rods are separated by 16 mm and mounted at 90-degree relative to one another. The pelvis phantom was filled with a solution of MnCl2 to mimic T2 relaxation time of the cervix (60-80 ms at 3T).Imaging was performed on a 3T Philips Achieva using a 16-channel Torso coil array. Four MR sequences were tested: T2-weighted fast spin-echo (T2w-FSE), proton density weighted FSE (PDw-FSE), T1-weighted FSE (T1w-FSE) and T1 weighted spoiled gradient echo (T1w-GE). The spatial resolution was kept the same between all sequences: 0.6 × 0.6 × 3 mm{sup 3} with no slice gaps. Para-sagittal images were acquired with the applicator fixed at a 30-degree angle anterior to the B0- field to mimic clinical settings. Results: Minimal artifacts were observed on T2w-FSE, PDw-FSE and T1-FSE, while significant artifacts were seen on T1w-GE images. Artifacts induced in all 3 FSE sequences did not hinder accurate localisation of the tip and the applicator boundaries. The drift of the applicator’s centreline from the radial fiducials was measured and found to be < 1 mm for the 3 FSE sequences. Conclusion: The tungsten–based DMBT applicator can be potentially used on 3T with various clinical sequences without inducing significant artifacts. Further validation on patients as well as the evaluation of relative SNR among the different sequences is required.

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

    Science.gov (United States)

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

    2010-09-01

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

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2010-09-21

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

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

    International Nuclear Information System (INIS)

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

    2010-01-01

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

  11. Phase modulation and structural effects in a D-shaped all-solid photonic crystal fiber surface plasmon resonance sensor.

    Science.gov (United States)

    Tan, Zhixin; Hao, Xin; Shao, Yonghong; Chen, Yuzhi; Li, Xuejin; Fan, Ping

    2014-06-16

    We numerically investigate a D-shaped fiber surface plasmon resonance sensor based on all-solid photonic crystal fiber (PCF) with finite element method. In the side-polished PCF sensor, field leakage is guided to penetrate through the gap between the rods, causing a pronounced phase modulation in the deep polishing case. Taking advantage of these amplified phase shifts, a high-performance fiber sensor design is proposed. The significant enhancements arising from this new sensor design should lift the performance of the fiber SPR sensor into the range capable of detecting a wide range of biochemical interactions, which makes it especially attractive for many in vivo and in situ bioanalysis applications. Several parameters which influence the field leakage, such as the polishing position, the pitch of the PCF, and the rod diameter, are inspected to evaluate their impacts. Furthermore, we develop a mathematical model to describe the effects of varying the structural parameters of a D-shaped PCF sensor on the evanescent field and the sensor performance.

  12. Development of Radioactive Inventory Evaluation System using 3D Shape and Multiple Radiation Measurement

    International Nuclear Information System (INIS)

    Lee, Sang Chul; Kim, Won Seok; Han, Byong Su; Moon, Joo Hyun

    2013-01-01

    The increase of the operating NPPs and the superannuation of the equipment in NPPs cause a large amount of the metal radioactive waste. Presently the metal radioactive wastes are stored in the temporary storage facility in NPPs because of the delay of the construction of the final disposal facility. The radioactive level of general metal radioactive wastes is low, and the radioactive level can be lowered by the simple decontamination process. If the radioactive wastes are disposed as the industry waste, the disposal cost is diminished largely. For the disposal of the radioactive wastes as the industrial wastes, the radioactive level of the target wastes are evaluated. It is difficult to know the position of the source term for most of the metal radioactive and the source term is distributed non-homogeneously. And the self-shielding effect of the metal material makes the evaluation more difficult. In this study, the radioactive inventory evaluation system for the metal radioactive waste is developed. For the correction of the uncertainty of the position and the non-homogeneity of the source term, the 3D shape and multiple radiation measurement are used. The existing gamma-ray measurement system for the metal radioactive waste cannot reflect the position and the distribution of the source term and the effect of self-shielding. This evaluation system suggested in this system can calculate the reasonable value regarding to the position and the distribution of the source term and the effect of self-shielding. By the calculation of the partial inventory of the target metal waste, the advantage in the application of the clearance criteria can be obtained

  13. Genetic Fuzzy Prediction of Mass Perception in Non-Functional 3D Shapes

    DEFF Research Database (Denmark)

    Achiche, Sofiane

    2010-01-01

    and it is argued that human attributes originate from three different levels of the brain: the visceral level; the behavioral level and the reflective level. This paper focuses upon the visceral level of reaction by automatically building a link between geometric properties of non-functional 3D shapes...

  14. WE-F-16A-01: Commissioning and Clinical Use of PC-ISO for Customized, 3D Printed, Gynecological Brachytherapy Applicators

    Energy Technology Data Exchange (ETDEWEB)

    Cunha, J; Sethi, R; Mellis, K; Siauw, T; Sudhyadhom, A; Hsu, I; Pouliot, J [UC San Francisco, San Francisco, CA (United States)

    2014-06-15

    Purpose: (1) Evaluate the safety and radiation attenuation properties of PCISO, a bio-compatible, sterilizable 3D printing material by Stratasys, (2) establish a method for commissioning customized multi- and single-use 3D printed applicators, (3) report on use of customized vaginal cylinders used to treat a series of serous endometrial cancer patient. Methods: A custom film dosimetry apparatus was designed to hold a Gafchromic radio film segment between two blocks of PC-ISO and 3D-printed using a Fortus 400mc (StrataSys). A dose plan was computed using 13 dwell positions at 2.5 mm spacing and normalized to 1500 cGy at 1 cm. Film exposure was compared to control tests in only air and only water. The average Hounsfield Unit (HU) was computed and used to verify water equivalency. For the clinical use cases, the physician specifies the dimensions and geometry of a custom applicator from which a CAD model is designed and printed. Results: The doses measured from the PC-ISO Gafchromic film test were within 1% of the dose measured in only water between 1cm and 6cm from the channel. Doses increased 7–4% measured in only air. HU range was 11–43. The applicators were sterilized using the Sterrad system multiple times without damage. As of submission 3 unique cylinders have been designed, printed, and used in the clinic. A standardizable workflow for commissioning custom 3D printed applicators was codified and will be reported. Conclusions: Quality assurance (QA) evaluation of the PC-ISO 3D-printing material showed that PC-ISO is a suitable material for a gynecological brachytherapy vaginal cylinder in a clinical setting. With the material commissioning completed, if the physician determines that a better treatment would Result, a customized design is fabricated with limited additional QA necessary. Although this study was specific to PC-ISO, the same setup can be used to evaluate other 3D-printing materials.

  15. WE-F-16A-01: Commissioning and Clinical Use of PC-ISO for Customized, 3D Printed, Gynecological Brachytherapy Applicators

    International Nuclear Information System (INIS)

    Cunha, J; Sethi, R; Mellis, K; Siauw, T; Sudhyadhom, A; Hsu, I; Pouliot, J

    2014-01-01

    Purpose: (1) Evaluate the safety and radiation attenuation properties of PCISO, a bio-compatible, sterilizable 3D printing material by Stratasys, (2) establish a method for commissioning customized multi- and single-use 3D printed applicators, (3) report on use of customized vaginal cylinders used to treat a series of serous endometrial cancer patient. Methods: A custom film dosimetry apparatus was designed to hold a Gafchromic radio film segment between two blocks of PC-ISO and 3D-printed using a Fortus 400mc (StrataSys). A dose plan was computed using 13 dwell positions at 2.5 mm spacing and normalized to 1500 cGy at 1 cm. Film exposure was compared to control tests in only air and only water. The average Hounsfield Unit (HU) was computed and used to verify water equivalency. For the clinical use cases, the physician specifies the dimensions and geometry of a custom applicator from which a CAD model is designed and printed. Results: The doses measured from the PC-ISO Gafchromic film test were within 1% of the dose measured in only water between 1cm and 6cm from the channel. Doses increased 7–4% measured in only air. HU range was 11–43. The applicators were sterilized using the Sterrad system multiple times without damage. As of submission 3 unique cylinders have been designed, printed, and used in the clinic. A standardizable workflow for commissioning custom 3D printed applicators was codified and will be reported. Conclusions: Quality assurance (QA) evaluation of the PC-ISO 3D-printing material showed that PC-ISO is a suitable material for a gynecological brachytherapy vaginal cylinder in a clinical setting. With the material commissioning completed, if the physician determines that a better treatment would Result, a customized design is fabricated with limited additional QA necessary. Although this study was specific to PC-ISO, the same setup can be used to evaluate other 3D-printing materials

  16. Effect of surface roughness variation on the transmission characteristics of D-shaped fibers with ambient index change

    International Nuclear Information System (INIS)

    Kim, Hyun-Joo; Kwon, Oh-Jang; Han, Young-Geun

    2010-01-01

    The influence of surface roughness on the sensitivity of D-shaped fibers to changes in the ambient index was investigated. In order to obtain D-shaped fibers with different surface roughness, we polished one side of the fibers by using different abrasive grits. The topographies of the surfaces of the polished D-shaped fibers were then observed by using atomic force microscopy (AFM). The light scattered from the rough surfaces of the D-shaped fibers was measured by using optical microscopy. The effect of an ambient index change on the transmission characteristics of D-shaped fibers was measured for various values of the surface roughness. The experimental results indicate that variations in the surface roughness have a considerable influence on the sensitivity of the transmission characteristics of D-shaped fibers to changes in the ambient index.

  17. Glass microspheres for brachytherapy

    International Nuclear Information System (INIS)

    Prado, Miguel O.; Prastalo, Simon; Blaumann, Herman; Longhino, Juan M.; Repetto Llamazares, A.H.V.

    2007-01-01

    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) [es

  18. Computed tomography in brachytherapy

    International Nuclear Information System (INIS)

    Mansfield, C.M.; Lee, K.R.; Dwyer, S.; Zellmer, D.; Cook, P.

    1983-01-01

    CT scanning adds to the ability to evaluate brachytherapy techniques. It provides an additional method in the assessment of patients who are candidates for or who are being treated by brachytherapy. The CT scan can give information regarding the position of the sources and their relation to the tumor and normal structures with greater ease than do orthogonal views. This makes it possible to accurately calculate areas of high or low dose. Potential areas of overdose can be recognized, thereby decreasing the chances of postbrachytherapy complications. CT scanning can be used at various levels of complexity in dosimetry evaluation. Adequate brachytherapy dosimetry information is obtainable from CT slices through one or more levels of the implanted volume. In some instances it is possible to obtain additional information by reconstructing the scans in other planes, e.g., coronal or sagittal. Three-dimensional viewing of the implant is desirable, but it should be pointed out that this approach is time-consuming and beyond the capabilities of most institutions at present. It will be necessary to continue work on three-dimensional treatment planning to make it readily available

  19. Navigation system for interstitial brachytherapy

    International Nuclear Information System (INIS)

    Strassmann, G.; Kolotas, C.; Heyd, R.

    2000-01-01

    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

  20. 2D-3D shape reconstruction of the distal femur from stereo X-Ray imaging using statistical shape models

    DEFF Research Database (Denmark)

    Baka, N.; Kaptein, B. L.; de Bruijne, Marleen

    2011-01-01

    Three-dimensional patient specific bone models are required in a range of medical applications, such as pre-operative surgery planning and improved guidance during surgery, modeling and simulation, and in vivo bone motion tracking. Shape reconstruction from a small number of X-ray images is desired...... as it lowers both the acquisition costs and the radiation dose compared to CT. We propose a method for pose estimation and shape reconstruction of 3D bone surfaces from two (or more) calibrated X-ray images using a statistical shape model (SSM). User interaction is limited to manual initialization of the mean...... pose estimation of ground truth shapes as well as 3D shape estimation using a SSM of the whole femur, from stereo cadaver X-rays, in vivo biplane fluoroscopy image-pairs, and an in vivo biplane fluoroscopic sequence. Ground truth shapes for all experiments were available in the form of CT segmentations...

  1. Perioperative high dose rate (HDR brachytherapy in unresectable locally advanced pancreatic tumors

    Directory of Open Access Journals (Sweden)

    Brygida Białas

    2011-07-01

    Full Text Available Purpose: The aim of the study was to present an original technique of catheter implantation for perioperative HDR-Ir192 brachytherapy in patients after palliative operations of unresectable locally advanced pancreatic tumors and to estimate the influence of perioperative HDR-Ir192 brachytherapy on pain relief in terminal pancreatic cancer patients. Material and methods: Eight patients with pancreatic tumors located in the head of pancreas underwent palliative operations with the use of HDR-Ir192 brachytherapy. All patients qualified for surgery reported pain of high intensity and had received narcotic painkillers prior to operation. During the last phase of the surgery, the Nucletron® catheters were implanted in patients to prepare them for later perioperative brachytherapy. Since the 6th day after surgery HDR brachytherapy was performed. Before each brachytherapy fraction the location of implants were checked using fluoroscopy. A fractional dose was 5 Gy and a total dose was 20 Gy in the area of radiation. A comparative study of two groups of patients (with and without brachytherapy with stage III pancreatic cancer according to the TNM scale was taken in consideration. Results and Conclusions: The authors claim that the modification of catheter implantation using specially designed cannula, facilitates the process of inserting the catheter into the tumor, shortens the time needed for the procedure, and reduces the risk of complications. Mean survival time was 5.7 months. In the group of performed brachytherapy, the mean survival time was 6.7 months, while in the group of no brachytherapy performed – 4.4 months. In the group of brachytherapy, only one patient increased the dose of painkillers in the last month of his life. Remaining patients took constant doses of medicines. Perioperative HDR-Ir192 brachytherapy could be considered as a practical application of adjuvant therapy for pain relief in patients with an advanced pancreatic cancer.

  2. Impact of systematic errors on DVH parameters of different OAR and target volumes in Intracavitary Brachytherapy (ICBT)

    International Nuclear Information System (INIS)

    Mourya, Ankur; Singh, Gaganpreet; Kumar, Vivek; Oinam, Arun S.

    2016-01-01

    Aim of this study is to analyze the impact of systematic errors on DVH parameters of different OAR and Target volumes in intracavitary brachytherapy (ICBT). To quantify the changes in dose-volume histogram parameters due to systematic errors in applicator reconstruction of brachytherapy planning, known errors in catheter reconstructions have to be introduced in applicator coordinate system

  3. Design and testing of a phantom and instrumented gynecological applicator based on GaN dosimeter for use in high dose rate brachytherapy quality assurance

    Energy Technology Data Exchange (ETDEWEB)

    Guiral, P.; Ribouton, J.; Jalade, P. [Service de Physique Médicale et Radioprotection, Centre Hospitalier Lyon Sud, Pierre-Bénite F-69495 (France); Wang, R.; Galvan, J.-M.; Lu, G.-N.; Pittet, P., E-mail: patrick.pittet@univ-lyon1.fr [Institut des Nanotechnologies de Lyon, University Lyon, Université Claude Bernard Lyon 1, CNRS, INL UMR5270, F-69622 Villeurbanne (France); Rivoire, A.; Gindraux, L. [DOSILAB, 66 Boulevard Niels Bohr, Villeurbanne F-69100 (France)

    2016-09-15

    Purpose: High dose rate brachytherapy (HDR-BT) is widely used to treat gynecologic, anal, prostate, head, neck, and breast cancers. These treatments are typically administered in large dose per fraction (>5 Gy) and with high-gradient-dose-distributions, with serious consequences in case of a treatment delivery error (e.g., on dwell position and dwell time). Thus, quality assurance (QA) or quality control (QC) should be systematically and independently implemented. This paper describes the design and testing of a phantom and an instrumented gynecological applicator for pretreatment QA and in vivo QC, respectively. Methods: The authors have designed a HDR-BT phantom equipped with four GaN-based dosimeters. The authors have also instrumented a commercial multichannel HDR-BT gynecological applicator by rigid incorporation of four GaN-based dosimeters in four channels. Specific methods based on the four GaN dosimeter responses are proposed for accurate determination of dwell time and dwell position inside phantom or applicator. The phantom and the applicator have been tested for HDR-BT QA in routine over two different periods: 29 and 15 days, respectively. Measurements in dwell position and time are compared to the treatment plan. A modified position–time gamma index is used to monitor the quality of treatment delivery. Results: The HDR-BT phantom and the instrumented applicator have been used to determine more than 900 dwell positions over the different testing periods. The errors between the planned and measured dwell positions are 0.11 ± 0.70 mm (1σ) and 0.01 ± 0.42 mm (1σ), with the phantom and the applicator, respectively. The dwell time errors for these positions do not exhibit significant bias, with a standard deviation of less than 100 ms for both systems. The modified position–time gamma index sets a threshold, determining whether the treatment run passes or fails. The error detectability of their systems has been evaluated through tests on

  4. Contemporary Toxicity Profile of Breast Brachytherapy Versus External Beam Radiation After Lumpectomy for Breast Cancer

    International Nuclear Information System (INIS)

    Huo, Jinhai; Giordano, Sharon H.; Smith, Benjamin D.; Shaitelman, Simona F.; Smith, Grace L.

    2016-01-01

    Purpose: We compared toxicities after brachytherapy versus external beam radiation therapy (EBRT) in contemporary breast cancer patients. Methods and Materials: Using MarketScan healthcare claims, we identified 64,112 women treated from 2003 to 2012 with lumpectomy followed by radiation (brachytherapy vs EBRT). Brachytherapy was further classified by multichannel versus single-channel applicator approach. We identified the risks and predictors of 1-year infectious and noninfectious postoperative adverse events using logistic regression and temporal trends using Cochran-Armitage tests. We estimated the 5-year Kaplan-Meier cumulative incidence of radiation-associated adverse events. Results: A total of 4522 (7.1%) patients received brachytherapy (50.2% multichannel vs 48.7% single-channel applicator). The overall risk of infectious adverse events was higher after brachytherapy than after EBRT (odds ratio [OR] = 1.21; 95% confidence interval [CI] 1.09-1.34, P<.001). However, over time, the frequency of infectious adverse events after brachytherapy decreased, from 17.3% in 2003 to 11.6% in 2012, and was stable after EBRT at 9.7%. Beyond 2007, there were no longer excess infections with brachytherapy (P=.97). The overall risk of noninfectious adverse events was higher after brachytherapy than after EBRT (OR=2.27; 95% CI 2.09-2.47, P<.0001). Over time, the frequency of noninfectious adverse events detected increased: after multichannel brachytherapy, from 9.1% in 2004 to 18.9% in 2012 (Ptrend = .64); single-channel brachytherapy, from 12.8% to 29.8% (Ptrend<.001); and EBRT, from 6.1% to 10.3% (Ptrend<.0001). The risk was significantly higher with single-channel than with multichannel brachytherapy (hazard ratio = 1.32; 95% CI 1.03-1.69, P=.03). Of noninfectious adverse events, 70.9% were seroma. Seroma significantly increased breast pain risk (P<.0001). Patients with underlying diabetes, cardiovascular disease, and treatment with chemotherapy had increased

  5. Contemporary Toxicity Profile of Breast Brachytherapy Versus External Beam Radiation After Lumpectomy for Breast Cancer

    Energy Technology Data Exchange (ETDEWEB)

    Huo, Jinhai [Department of Health Services Research, The University of Texas MD Anderson Cancer Center, Houston, Texas (United States); Giordano, Sharon H. [Department of Health Services Research, The University of Texas MD Anderson Cancer Center, Houston, Texas (United States); Department of Breast Medical Oncology, The University of Texas MD Anderson Cancer Center, Houston, Texas (United States); Smith, Benjamin D. [Department of Health Services Research, The University of Texas MD Anderson Cancer Center, Houston, Texas (United States); Department of Radiation Oncology, The University of Texas MD Anderson Cancer Center, Houston, Texas (United States); Shaitelman, Simona F. [Department of Radiation Oncology, The University of Texas MD Anderson Cancer Center, Houston, Texas (United States); Smith, Grace L., E-mail: glsmith@mdanderson.org [Department of Health Services Research, The University of Texas MD Anderson Cancer Center, Houston, Texas (United States); Department of Radiation Oncology, The University of Texas MD Anderson Cancer Center, Houston, Texas (United States)

    2016-03-15

    Purpose: We compared toxicities after brachytherapy versus external beam radiation therapy (EBRT) in contemporary breast cancer patients. Methods and Materials: Using MarketScan healthcare claims, we identified 64,112 women treated from 2003 to 2012 with lumpectomy followed by radiation (brachytherapy vs EBRT). Brachytherapy was further classified by multichannel versus single-channel applicator approach. We identified the risks and predictors of 1-year infectious and noninfectious postoperative adverse events using logistic regression and temporal trends using Cochran-Armitage tests. We estimated the 5-year Kaplan-Meier cumulative incidence of radiation-associated adverse events. Results: A total of 4522 (7.1%) patients received brachytherapy (50.2% multichannel vs 48.7% single-channel applicator). The overall risk of infectious adverse events was higher after brachytherapy than after EBRT (odds ratio [OR] = 1.21; 95% confidence interval [CI] 1.09-1.34, P<.001). However, over time, the frequency of infectious adverse events after brachytherapy decreased, from 17.3% in 2003 to 11.6% in 2012, and was stable after EBRT at 9.7%. Beyond 2007, there were no longer excess infections with brachytherapy (P=.97). The overall risk of noninfectious adverse events was higher after brachytherapy than after EBRT (OR=2.27; 95% CI 2.09-2.47, P<.0001). Over time, the frequency of noninfectious adverse events detected increased: after multichannel brachytherapy, from 9.1% in 2004 to 18.9% in 2012 (Ptrend = .64); single-channel brachytherapy, from 12.8% to 29.8% (Ptrend<.001); and EBRT, from 6.1% to 10.3% (Ptrend<.0001). The risk was significantly higher with single-channel than with multichannel brachytherapy (hazard ratio = 1.32; 95% CI 1.03-1.69, P=.03). Of noninfectious adverse events, 70.9% were seroma. Seroma significantly increased breast pain risk (P<.0001). Patients with underlying diabetes, cardiovascular disease, and treatment with chemotherapy had increased

  6. Optical properties study of nano-composite filled D shape photonic crystal fibre

    Science.gov (United States)

    Udaiyakumar, R.; Mohamed Junaid, K. A.; Janani, T.; Maheswar, R.; Yupapin, P.; Amiri, I. S.

    2018-06-01

    With the nano-composite materials gaining momentum in the optical field, a new nano-composite filled D shape Photonic Crystal Fiber (PCF) is designed and the various optical properties are investigated with help of Finite Element Method. In the proposed structure the D-shape PCF is made up of silica with embedded silver nanoparticles and air holes are distributed along the fibre. The designed fibre shows various optical properties such as dispersion, birefringence, beat length and loss with respect to wavelength and compared with different filling factor like 0.1, 0.3 and 0.5. From our estimation and comparative analysis, it has been proved that the fibre loss has been decreased with increasing filling factor. Further this also showed flat dispersion at maximum filling factor.

  7. Optical properties study of nano-composite filled D shape photonic crystal fibre

    Directory of Open Access Journals (Sweden)

    R. Udaiyakumar

    2018-06-01

    Full Text Available With the nano-composite materials gaining momentum in the optical field, a new nano-composite filled D shape Photonic Crystal Fiber (PCF is designed and the various optical properties are investigated with help of Finite Element Method. In the proposed structure the D-shape PCF is made up of silica with embedded silver nanoparticles and air holes are distributed along the fibre. The designed fibre shows various optical properties such as dispersion, birefringence, beat length and loss with respect to wavelength and compared with different filling factor like 0.1, 0.3 and 0.5. From our estimation and comparative analysis, it has been proved that the fibre loss has been decreased with increasing filling factor. Further this also showed flat dispersion at maximum filling factor. Keywords: Nanoparticles, Nano-composite, Dispersion, Birefringence, Beat length

  8. A fibre optic dosimeter customised for brachytherapy

    Energy Technology Data Exchange (ETDEWEB)

    Suchowerska, N. [Department of Radiation Oncology, Royal Prince Alfred Hospital, Camperdown, NSW 2050 (Australia); School of Physics, University of Sydney, NSW 2006 (Australia)], E-mail: Natalka@email.cs.nsw.gov.au; Lambert, J.; Nakano, T. [Department of Radiation Oncology, Royal Prince Alfred Hospital, Camperdown, NSW 2050 (Australia); School of Physics, University of Sydney, NSW 2006 (Australia); Law, S. [School of Physics, University of Sydney, NSW 2006 (Australia); Optical Fibre Technology Centre, University of Sydney, 206 National Innovation Centre, Australian Technology Park, Eveleigh, NSW 1430 (Australia); Elsey, J. [Bandwidth Foundry Pty Ltd, Australian Technology Park, NSW, 1430 (Australia); McKenzie, D.R. [School of Physics, University of Sydney, NSW 2006 (Australia)

    2007-04-15

    In-vivo dosimetry for brachytherapy cancer treatment requires a small dosimeter with a real time readout capability that can be inserted into the patient to determine the dose to critical organs. Fibre optic scintillation dosimeters, consisting of a plastic scintillator coupled to an optical fibre, are a promising dosimeter for this application. We have implemented specific design features to optimise the performance of the dosimeter for specific in-vivo dosimetry during brachytherapy. Two sizes of the BrachyFOD{sup TM} scintillation dosimeter have been developed, with external diameters of approximately 2 and 1 mm. We have determined their important dosimetric characteristics (depth dose relation, angular dependence, energy dependence). We have shown that the background signal created by Cerenkov and fibre fluorescence does not significantly affect the performance in most clinical geometries. The dosimeter design enables readout at less than 0.5 s intervals. The clinical demands of real time in-vivo brachytherapy dosimetry can uniquely be satisfied by the BrachyFOD{sup TM}.

  9. Deep Correlated Holistic Metric Learning for Sketch-Based 3D Shape Retrieval.

    Science.gov (United States)

    Dai, Guoxian; Xie, Jin; Fang, Yi

    2018-07-01

    How to effectively retrieve desired 3D models with simple queries is a long-standing problem in computer vision community. The model-based approach is quite straightforward but nontrivial, since people could not always have the desired 3D query model available by side. Recently, large amounts of wide-screen electronic devices are prevail in our daily lives, which makes the sketch-based 3D shape retrieval a promising candidate due to its simpleness and efficiency. The main challenge of sketch-based approach is the huge modality gap between sketch and 3D shape. In this paper, we proposed a novel deep correlated holistic metric learning (DCHML) method to mitigate the discrepancy between sketch and 3D shape domains. The proposed DCHML trains two distinct deep neural networks (one for each domain) jointly, which learns two deep nonlinear transformations to map features from both domains into a new feature space. The proposed loss, including discriminative loss and correlation loss, aims to increase the discrimination of features within each domain as well as the correlation between different domains. In the new feature space, the discriminative loss minimizes the intra-class distance of the deep transformed features and maximizes the inter-class distance of the deep transformed features to a large margin within each domain, while the correlation loss focused on mitigating the distribution discrepancy across different domains. Different from existing deep metric learning methods only with loss at the output layer, our proposed DCHML is trained with loss at both hidden layer and output layer to further improve the performance by encouraging features in the hidden layer also with desired properties. Our proposed method is evaluated on three benchmarks, including 3D Shape Retrieval Contest 2013, 2014, and 2016 benchmarks, and the experimental results demonstrate the superiority of our proposed method over the state-of-the-art methods.

  10. The influence of training views on infants' long-term memory for simple 3D shapes.

    Science.gov (United States)

    Kraebel, Kimberly S; West, Rebecca N; Gerhardstein, Peter

    2007-05-01

    This investigation explored infants' ability to retrieve a memory for a simple 3D shape from a novel view following a 24-hr delay. Tests of memory for shape in infancy have typically used extremely short delay intervals between familiarization and test in examining the ability to equate between substantially different views of a 3D object. The current study used longer delays to assess the content of a long-term memory representation. Infants 3-4 months of age learned to kick to move a mobile displaying a simple 3D shape (brick or cylinder). Results of three experiments show that infants can recognize 3D shapes in a novel viewpoint across a 24-hr delay, provided that experience with a sufficiently wide range of views is available during training. The results suggest a capacity for the perception of 3D shape that enables access, across long delays, to a memory representation of sufficient detail that discrimination between two simple shapes (i.e., a cylinder and a brick) is possible. The results suggest that this representation is of a sufficiently abstract nature that perception of the 3D form of the object, independent of the changes in specific features accompanying changes in viewpoint, is also possible. This finding suggests that infants, like adults, possess a functional memory system for the distal shape of simple 3D objects, and can transfer training to a novel view using long-term memory, but that this ability is not as strong as in the mature system. These results have implications for the development of shape perception and for theories of object recognition in general. (c) 2007 Wiley Periodicals, Inc.

  11. 3D shape representation with spatial probabilistic distribution of intrinsic shape keypoints

    Science.gov (United States)

    Ghorpade, Vijaya K.; Checchin, Paul; Malaterre, Laurent; Trassoudaine, Laurent

    2017-12-01

    The accelerated advancement in modeling, digitizing, and visualizing techniques for 3D shapes has led to an increasing amount of 3D models creation and usage, thanks to the 3D sensors which are readily available and easy to utilize. As a result, determining the similarity between 3D shapes has become consequential and is a fundamental task in shape-based recognition, retrieval, clustering, and classification. Several decades of research in Content-Based Information Retrieval (CBIR) has resulted in diverse techniques for 2D and 3D shape or object classification/retrieval and many benchmark data sets. In this article, a novel technique for 3D shape representation and object classification has been proposed based on analyses of spatial, geometric distributions of 3D keypoints. These distributions capture the intrinsic geometric structure of 3D objects. The result of the approach is a probability distribution function (PDF) produced from spatial disposition of 3D keypoints, keypoints which are stable on object surface and invariant to pose changes. Each class/instance of an object can be uniquely represented by a PDF. This shape representation is robust yet with a simple idea, easy to implement but fast enough to compute. Both Euclidean and topological space on object's surface are considered to build the PDFs. Topology-based geodesic distances between keypoints exploit the non-planar surface properties of the object. The performance of the novel shape signature is tested with object classification accuracy. The classification efficacy of the new shape analysis method is evaluated on a new dataset acquired with a Time-of-Flight camera, and also, a comparative evaluation on a standard benchmark dataset with state-of-the-art methods is performed. Experimental results demonstrate superior classification performance of the new approach on RGB-D dataset and depth data.

  12. Constraints in the use of repair half times and mathematical modelling for the clinical application of HDR and PDR treatment schedules as an alternative for LDR brachytherapy

    International Nuclear Information System (INIS)

    Pop, L.A.M.; Broek, J.F.C.M. van den; Visser, A.G.; Kogel, A.J. van der

    1996-01-01

    Using theoretical models based on radiobiological principles for the design of new treatment schedules for HDR and PDR brachytherapy, it is important to realise the impact of assumptions regarding the kinetics of repair. Extrapolations based on longer repair half times in a continuous LDR reference scheme may lead to the calculation of dangerously high doses for alternative HDR and PDR treatment schedules. We used the clinical experience obtained with conventional ERT and LDR brachytherapy in head and neck cancer as a clinical guideline to check the impact of the radiobiological parameters used. Biologically equivalent dose (BED) values for the in clinical practice of LDR brachytherapy recommended dose of 65-70 Gy (prescribed at a dose rate between 30-50 cGy/h) are calculated as a function of the repair half time. These BED values are compared with the biological effect of a clinical reference dose of conventional ERT with 2 Gy/day and complete repair between the fractions. From this comparison of LDR and ERT treatment schedules, a range of values for the repair half times of acute or late responding tissues is demarcated with a reasonable fit to the clinical data. For the acute effects (or tumor control) the best fits are obtained for repair half times of about 0.5 h, while for late effects the repair half times are at least 1 h and can be as high as 3 h. Within these ranges of repair half times for acute and late effects, the outcome of 'alternative' HDR or PDR treatment schedules are discussed. It is predominantly the late reacting normal tissue with the longer repair half time for which problems will be encountered and no or only marginal gain is to be expected of decreasing the dose rate per pulse in PDR brachytherapy

  13. SU-G-201-01: An Automated Treatment Plan Quality Assurance Program for High-Dose Rate (HDR) Brachytherapy with a VaginalCylinder Applicator

    Energy Technology Data Exchange (ETDEWEB)

    Zhou, Y; Tan, J; Jiang, S; Albuquerque, K; Jia, X [UT Southwestern Medical Center, Dallas, TX (United States)

    2016-06-15

    Purpose: Plan specific quality assurance (QA) is an important step in high dose rate (HDR) brachytherapy to ensure the integrity of a treatment plan. The conventional approach is to assemble a set of plan screen-captures in a document and have an independent plan-checker to verify it. Not only is this approach cumbersome and time-consuming, using a document also limits the items that can be verified, hindering plan quality and patient safety. We have initiated efforts to develop a web-based HDR brachytherapy QA system called AutoBrachy QA, for comprehensive and efficient QA. This abstract reports a new plugin in this system for the QA of a cylinder HDR brachytherapy treatment. Methods: A cylinder plan QA module was developed using Python. It was plugged into our AutoBrachy QA system. This module extracted information from CT images and treatment plan. Image processing techniques were employed to obtain geometric parameters, e.g. cylinder diameter. A comprehensive set of eight geometrical and eight dosimetric features of the plan were validated against user specified planning parameter, such as prescription value, treatment depth and length, etc. A PDF document was generated, consisting of a summary QA sheet with all the QA results, as well as images showing plan details. Results: The cylinder QA program has been implemented in our clinic. To date, it has been used in 11 patient cases and was able to successfully perform QA tests in all of them. The QA program reduced the average plan QA time from 7 min using conventional manual approach to 0.5 min. Conclusion: Being a new module in our AutoBrachy QA system, an automated treatment plan QA module for cylinder HDR brachytherapy has been successfully developed and clinically implemented. This module improved clinical workflow and plan integrity compared to the conventional manual approach.

  14. SU-G-201-01: An Automated Treatment Plan Quality Assurance Program for High-Dose Rate (HDR) Brachytherapy with a VaginalCylinder Applicator

    International Nuclear Information System (INIS)

    Zhou, Y; Tan, J; Jiang, S; Albuquerque, K; Jia, X

    2016-01-01

    Purpose: Plan specific quality assurance (QA) is an important step in high dose rate (HDR) brachytherapy to ensure the integrity of a treatment plan. The conventional approach is to assemble a set of plan screen-captures in a document and have an independent plan-checker to verify it. Not only is this approach cumbersome and time-consuming, using a document also limits the items that can be verified, hindering plan quality and patient safety. We have initiated efforts to develop a web-based HDR brachytherapy QA system called AutoBrachy QA, for comprehensive and efficient QA. This abstract reports a new plugin in this system for the QA of a cylinder HDR brachytherapy treatment. Methods: A cylinder plan QA module was developed using Python. It was plugged into our AutoBrachy QA system. This module extracted information from CT images and treatment plan. Image processing techniques were employed to obtain geometric parameters, e.g. cylinder diameter. A comprehensive set of eight geometrical and eight dosimetric features of the plan were validated against user specified planning parameter, such as prescription value, treatment depth and length, etc. A PDF document was generated, consisting of a summary QA sheet with all the QA results, as well as images showing plan details. Results: The cylinder QA program has been implemented in our clinic. To date, it has been used in 11 patient cases and was able to successfully perform QA tests in all of them. The QA program reduced the average plan QA time from 7 min using conventional manual approach to 0.5 min. Conclusion: Being a new module in our AutoBrachy QA system, an automated treatment plan QA module for cylinder HDR brachytherapy has been successfully developed and clinically implemented. This module improved clinical workflow and plan integrity compared to the conventional manual approach.

  15. Dosimetric Comparison of 3-Dimensional Planning Techniques Using an Intravaginal Multichannel Balloon Applicator for High-Dose-Rate Gynecologic Brachytherapy

    Energy Technology Data Exchange (ETDEWEB)

    Park, Sang-June, E-mail: spark@mednet.ucla.edu; Chung, Melody; Demanes, D. Jeffrey; Banerjee, Robyn; Steinberg, Michael; Kamrava, Mitchell

    2013-11-15

    Purpose: To study the dosimetric differences of various channel combinations of the Capri vaginal applicator. Methods and Materials: The Capri consists of a single central channel (R1), an inner array of 6 channels (R2), and an outer array of 6 channels (R3). Three-dimensional plans were simulated for 6 channel arrangements (R1, R2, R12, R13, R23, and R123). Treatment plans were optimized to the applicator surface or 5-mm depth while minimizing dose to organs at risk (OARs: bladder, rectum, sigmoid, and urethra). The clinical target volume (CTV) was defined as a 5-mm circumferential shell extending 4 cm in length around the applicator. Clinical target volume coverage (D{sub mean}, D{sub 90}, V{sub 100}, and V{sub 150}) and OAR doses (D{sub 0.1} {sub cm{sup 3}}, D{sub 1} {sub cm{sup 3}}, D{sub 2} {sub cm{sup 3}}, and D{sub mean}) were compared. A comparison between the Capri (R123) and a conventional single-channel applicator was also done. Statistical significance (P value <.05) was evaluated with a 2-tailed t test. Results: When prescribing to 5-mm depth, CTV coverage using all 13 channels (R123) versus a single channel (R1) was similar; however, when prescribing to the surface there were differences (P<.0001) in all CTV metrics except for the V{sub 150}. The R1 plans had higher doses to all OARs compared with R123 plans (P<.007). Doses to OARs were not significantly different between R23 and R123 plans (P=.05-.95), and CTV coverage differences were on the order of 1%. Capri R123 plans provided slightly lower CTV D{sub 90} and D{sub mean} but equivalent OAR doses with smaller standard deviations compared with conventional cylinder plans for both prescriptions. Conclusions: The Capri multichannel applicator provides equivalent target coverage at 5-mm depth, with significantly reduced dose to OARs relative to using a single channel. Optimal plans can be achieved using R12 (lowest V{sub 150}) or R123 or R23 (lowest OAR doses)

  16. Intra coronary brachytherapy

    International Nuclear Information System (INIS)

    Ghofourian, H.; Ghahremani, A.; Oliaie, A.; Taghizadeh Asl, M.

    2002-01-01

    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 g races b eing 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

  17. WE-F-BRD-01: HDR Brachytherapy II: Integrating Imaging with HDR

    Energy Technology Data Exchange (ETDEWEB)

    Craciunescu, O [Duke University Medical Center, Durham, NC (United States); Todor, D [Virginia Commonwealth University, Richmond, VA (United States); Leeuw, A de

    2014-06-15

    In recent years, with the advent of high/pulsed dose rate afterloading technology, advanced treatment planning systems, CT/MRI compatible applicators, and advanced imaging platforms, image-guided adaptive brachytherapy treatments (IGABT) have started to play an ever increasing role in modern radiation therapy. The most accurate way to approach IGABT treatment is to provide the infrastructure that combines in a single setting an appropriate imaging device, a treatment planning system, and a treatment unit. The Brachytherapy Suite is not a new concept, yet the modern suites are incorporating state-of-the-art imaging (MRI, CBCT equipped simulators, CT, and /or US) that require correct integration with each other and with the treatment planning and delivery systems. Arguably, an MRI-equipped Brachytherapy Suite is the ideal setup for real-time adaptive brachytherapy treatments. The main impediment to MRI-IGABT adoption is access to MRI scanners. Very few radiation oncology departments currently house MRI scanners, and even fewer in a dedicated Brachytherapy Suite. CBCT equipped simulators are increasingly offered by manufacturers as part of a Brachytherapy Suite installation. If optimized, images acquired can be used for treatment planning, or can be registered with other imaging modalities. This infrastructure is relevant for all forms of brachytherapy, especially those utilizing multi-fractionated courses of treatment such as prostate and cervix. Moreover, for prostate brachytherapy, US imaging systems can be part of the suite to allow for real-time HDR/LDR treatments. Learning Objectives: Understand the adaptive workflow of MR-based IGBT for cervical cancer. Familiarize with commissioning aspects of a CBCT equipped simulator with emphasis on brachytherapy applications Learn about the current status and future developments in US-based prostate brachytherapy.

  18. WE-F-BRD-01: HDR Brachytherapy II: Integrating Imaging with HDR

    International Nuclear Information System (INIS)

    Craciunescu, O; Todor, D; Leeuw, A de

    2014-01-01

    In recent years, with the advent of high/pulsed dose rate afterloading technology, advanced treatment planning systems, CT/MRI compatible applicators, and advanced imaging platforms, image-guided adaptive brachytherapy treatments (IGABT) have started to play an ever increasing role in modern radiation therapy. The most accurate way to approach IGABT treatment is to provide the infrastructure that combines in a single setting an appropriate imaging device, a treatment planning system, and a treatment unit. The Brachytherapy Suite is not a new concept, yet the modern suites are incorporating state-of-the-art imaging (MRI, CBCT equipped simulators, CT, and /or US) that require correct integration with each other and with the treatment planning and delivery systems. Arguably, an MRI-equipped Brachytherapy Suite is the ideal setup for real-time adaptive brachytherapy treatments. The main impediment to MRI-IGABT adoption is access to MRI scanners. Very few radiation oncology departments currently house MRI scanners, and even fewer in a dedicated Brachytherapy Suite. CBCT equipped simulators are increasingly offered by manufacturers as part of a Brachytherapy Suite installation. If optimized, images acquired can be used for treatment planning, or can be registered with other imaging modalities. This infrastructure is relevant for all forms of brachytherapy, especially those utilizing multi-fractionated courses of treatment such as prostate and cervix. Moreover, for prostate brachytherapy, US imaging systems can be part of the suite to allow for real-time HDR/LDR treatments. Learning Objectives: Understand the adaptive workflow of MR-based IGBT for cervical cancer. Familiarize with commissioning aspects of a CBCT equipped simulator with emphasis on brachytherapy applications Learn about the current status and future developments in US-based prostate brachytherapy

  19. Development of brachytherapy medium doserate

    International Nuclear Information System (INIS)

    Atang Susila; Ari Satmoko; Ahmad Rifai; Kristiyanti

    2010-01-01

    Brachytherapy has proven to be an effective treatment for different types of cancers and it become a common treatment modality in most radiotherapy clinics. PRPN has had experience in development of Low Dose Rate Brachytherapy for cervix cancer treatment. However the treatment process using LDR device needs 5 hours in time that the patient feel uncomfort. Therefore PRPN develops Medium Dose Rate Brachytherapy with radiation activity not more than 5 Currie. The project is divided into two stages. Purchasing of TPS software and TDS design are held in 2010, and the construction will be in 2011. (author)

  20. Estimates of relative doses of {sup 106}Ru/{sup 106}Rh of spherical applicators used in ophthalmic brachytherapy; Estimativas de doses relativas de aplicadores esfericos de {sup 106}Ru/{sup 106}Rh usados em braquiterapia oftalmologica

    Energy Technology Data Exchange (ETDEWEB)

    Paiva, Eduardo de, E-mail: edup2112@gmail.com, E-mail: epaiva@ird.gov.br [Instituto de Radioprotecao e Dosimetria (IRD/CNEN-RJ), Rio de Janeiro, RJ (Brazil). Div. de Fisica Medica

    2016-11-01

    Spherical ophthalmic applicators containing the beta emitter {sup 106}Ru / {sup 106}Rh are much used in brachytherapy for the treatment of various eye diseases. However, there is great difficulty in dosimetry these sources because of its geometric shape, the short range of the beta particles and the large dose gradient, and because of that calculation methods of dose distributions around these sources take on a great importance. In this work an analytical / numerical method is used to estimate the dose rates for a function of depth for spherical sources containing {sup 106}Ru / {sup 106}Rh. The results of the doses on along the central axis for applicators models CXS, CCX, CCY, CCZ, CCD and CGD and CCC are compared with published values calculated by Monte Carlo simulation and measurement results.

  1. [Developments in brachytherapy].

    Science.gov (United States)

    Ikeda, H

    1995-09-01

    Brachytherapy is one of the ideal methods of radiotherapy because of the concentration of a high dose on the target. Recent developments, including induction of afterloading method, utilization of small-sized high-activity sources such as Iridium-192, and induction of high technology and computerization, have made for shortening of irradiation time and source handling, which has led to easier management of the patient during treatment. Dose distribution at high dose rate (HDR) is at least as good as that of low dose rate (LDR), and selection of fractionation and treatment time assures even greater biological effects on hypoxic tumor cells than LDR. Experience with HDR brachytherapy in uterine cervix cancer using Cobalt-60 during the past 20 years in this country has gradually been evaluated in U.S. and Europe. The indications for HDR treatment have extended to esophagus, bronchus, bile duct, brain, intraoperative placement of source guide, and perineal region using templates, as well as the conventional use for uterus, tongue and so on.

  2. Algorithms for the process management of sealed source brachytherapy

    International Nuclear Information System (INIS)

    Engler, M.J.; Ulin, K.; Sternick, E.S.

    1996-01-01

    Incidents and misadministrations suggest that brachytherapy may benefit form clarification of the quality management program and other mandates of the US Nuclear Regulatory Commission. To that end, flowcharts of step by step subprocesses were developed and formatted with dedicated software. The overall process was similarly organized in a complex flowchart termed a general process map. Procedural and structural indicators associated with each flowchart and map were critiqued and pre-existing documentation was revised. open-quotes Step-regulation tablesclose quotes were created to refer steps and subprocesses to Nuclear Regulatory Commission rules and recommendations in their sequences of applicability. Brachytherapy algorithms were specified as programmable, recursive processes, including therapeutic dose determination and monitoring doses to the public. These algorithms are embodied in flowcharts and step-regulation tables. A general algorithm is suggested as a template form which other facilities may derive tools to facilitate process management of sealed source brachytherapy. 11 refs., 9 figs., 2 tabs

  3. 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

  4. Investigation of Interfraction Variations of MammoSite Balloon Applicator in High-Dose-Rate Brachytherapy of Partial Breast Irradiation

    International Nuclear Information System (INIS)

    Kim, Yongbok; Johnson, Mark M.S.; Trombetta, Mark G.; Parda, David S.; Miften, Moyed

    2008-01-01

    Purpose: To measure the interfraction changes of the MammoSite applicator and evaluate their dosimetric effect on target coverage and sparing of organs at risk. Methods and Materials: A retrospective evaluation of the data from 19 patients who received 10 fractions (34 Gy) of high-dose-rate partial breast irradiation was performed. A computed tomography-based treatment plan was generated for Fraction 1, and a computed tomography scan was acquired just before the delivery of each fraction to ensure a consistent shape of the balloon. The eccentricity, asymmetry, and planning target volume (PTV) for plan evaluation purposes (PTV E VAL), as well as trapped air gaps, were measured for all patients. Furthermore, 169 computed tomography-based treatment plans were retrospectively generated for Fractions 2-10. Interfraction dosimetric variations were evaluated using the %PTV E VAL coverage, target dose homogeneity index, target dose conformal index, and maximum doses to the organs at risks. Results: The average variation of eccentricity and asymmetry from Fraction 1 values of 3.5% and 1.1 mm was -0.4% ± 1.6% and -0.1 ± 0.6 mm. The average trapped air gap volume was dramatically reduced from before treatment (3.7 cm 3 ) to Fraction 1 (0.8 cm 3 ). The PTV E VAL volume change was insignificant. The average variation for the %PTV E VAL, target dose homogeneity, and target dose conformal index from Fraction 1 values of 94.7%, 0.64, and 0.85 was 0.15% ± 2.4%, -0.35 ± 2.4%, and -0.34 ± 4.9%, respectively. The average Fraction 1 maximum skin and ipsilateral lung dose of 3.2 Gy and 2.0 Gy varied by 0.08 ± 0.47 and -0.16 ± 0.29 Gy, respectively. Conclusion: The interfraction variations were patient specific and fraction dependent. Although the average interfraction dose variations for the target and organs at risk were not clinically significant, the maximum variations could be clinically significant

  5. Programming 2D/3D shape-shifting with hobbyist 3D printers† †Electronic supplementary information (ESI) available. See DOI: 10.1039/c7mh00269f

    Science.gov (United States)

    van Manen, Teunis; Janbaz, Shahram

    2017-01-01

    Materials and devices with advanced functionalities often need to combine complex 3D shapes with functionality-inducing surface features. Precisely controlled bio-nanopatterns, printed electronic components, and sensors/actuators are all examples of such surface features. However, the vast majority of the refined technologies that are currently available for creating functional surface features work only on flat surfaces. Here we present initially flat constructs that upon triggering by high temperatures change their shape to a pre-programmed 3D shape, thereby enabling the combination of surface-related functionalities with complex 3D shapes. A number of shape-shifting materials have been proposed during the last few years based on various types of advanced technologies. The proposed techniques often require multiple fabrication steps and special materials, while being limited in terms of the 3D shapes they could achieve. The approach presented here is a single-step printing process that requires only a hobbyist 3D printer and inexpensive off-the-shelf materials. It also lends itself to a host of design strategies based on self-folding origami, instability-driven pop-up, and ‘sequential’ shape-shifting to unprecedentedly expand the space of achievable 3D shapes. This combination of simplicity and versatility is a key to widespread applications. PMID:29308207

  6. Brachytherapy in childhood rhabdomyosarcoma treatment

    International Nuclear Information System (INIS)

    Novaes, Paulo Eduardo Ribeiro dos Santos

    1995-01-01

    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 Gold 198 , Cesium 137 and Iridium 192 . 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)

  7. Construction of a 3D-shaped, natural product like fragment library by fragmentation and diversification of natural products.

    Science.gov (United States)

    Prescher, Horst; Koch, Guido; Schuhmann, Tim; Ertl, Peter; Bussenault, Alex; Glick, Meir; Dix, Ina; Petersen, Frank; Lizos, Dimitrios E

    2017-02-01

    A fragment library consisting of 3D-shaped, natural product-like fragments was assembled. Library construction was mainly performed by natural product degradation and natural product diversification reactions and was complemented by the identification of 3D-shaped, natural product like fragments available from commercial sources. In addition, during the course of these studies, novel rearrangements were discovered for Massarigenin C and Cytochalasin E. The obtained fragment library has an excellent 3D-shape and natural product likeness, covering a novel, unexplored and underrepresented chemical space in fragment based drug discovery (FBDD). Copyright © 2016 Elsevier Ltd. All rights reserved.

  8. Critical β of a D-shaped toroidal plasma with sharp boundary

    International Nuclear Information System (INIS)

    Kito, M.

    1981-01-01

    Under the cap-cyclide coordinate system, the marginal stability of a sharp boundary toroidal plasma whose cross section is D shaped is examined using the energy principle. The analytical results are valid for arbitrary b, arbitrary aspect ratio, and arbitrary elongation of the plasma. There exists a maximum elongation for a given aspect ratio. The critical beta b/sub c/ is computed for several aspect ratios and elongations. For given aspect ratio, b/sub c/ increases as long as the elongation increases

  9. 3D shape detection of the indoor space based on 3D-Hough method

    OpenAIRE

    安齋, 達也; ANZAI, Tatsuya

    2013-01-01

    This paper describes methods for detecting the 3D shapes of the indoor space that is represented as a combination of planes such as a wall, desk, or whatnot. Detecting the planes makes it possible to perform calibration of multiple sensors and 3D mapping, and then produces various services such as the acquisition of life logs, AR interaction, and invader detection. This paper proposes and verifies three algorithms. First, it mentions a way to use2D-Hough.The proposed technique converts 3D dat...

  10. The utilization of mind map painting on 3D shapes with curved faces

    Science.gov (United States)

    Nur Sholikhah, Ayuk; Usodo, Budi; Pramudya, Ikrar

    2017-12-01

    This paper aims to study on the use of mind map painting media on material with 3D shapes with curved faces and its effect on student’s interest. Observation and literature studies were applied as the research method with the sake design of utilization of mind map painting. The result of this research is the design of mind map painting media can improve students' ability to solve problems, improve the ability to think, and maximize brain power. In relation, mind map painting in learning activities is considered to improve student interest.

  11. An afterloading brachytherapy device utilizing thermoplastic material

    International Nuclear Information System (INIS)

    Kim, T.H.; Gerbi, J.B.; Deibel, F.C.; Khan, F.M.; Priest, J.R.

    1989-01-01

    An afterloading brachytherapy device for treatment of residual cancer in an enucleated orbit with two cesium-137 sources was designed using a thermoplastic material, Aquaplast. The device consists of a face-mask support held in place with elastic bands around the head and an acrylic afterloading applicator. The device is very easy to make, holds the sources firmly in place, allows full mobility of the patient, and gives excellent dose distribution to the target area. It was easily tolerated by a 7-year-old child during the 50 h of treatment. (author). 3 refs.; 4 figs

  12. American brachytherapy society (ABS) guidelines for brachytherapy of esophageal cancer

    International Nuclear Information System (INIS)

    Nag, Subir; Gaspar, Laurie; Herskovic, Arnold; Mantravadi, Prasad; Speiser, Burton

    1996-01-01

    Introduction: There is wide variation in the indications, techniques, treatment regimens and dosimetry being used to treat cancer of the esophagus and no guidelines exist for optimal therapy. Methods: The Clinical Research Committee of the ABS met to formulate consensus guidelines for brachytherapy in esophageal cancer. Results: Good candidates for brachytherapy include patients with unifocal disease, with thoracic tumor 10 cm primary regional lymph adenopathy or tumor located in the gastro-esophageal junction or cervical esophagus. Contraindications include tracheo-esophageal fistula or stenosis that cannot be by-passed. The esophageal or nasogastric tube inserted should have a diameter of 6-10 mm whenever possible. If 5FU-based chemotherapy and 50 Gy external beam (EBRT) are used, it is suggested that the low dose rate brachytherapy (LDR) dose be 20 Gy at 0.4-1 Gy/hr, prescribed at 1 cm from the source. If high dose rate (HDR) is used, the dose recommended is 10 Gy in 2 weekly fractions of 5 Gy each, given after EBRT. Chemotherapy is not usually given concurrently with brachytherapy, and when it is, the brachytherapy dose is reduced. The length of esophagus treated by brachytherapy includes the post-EBRT involved area and a 1-2 cm margin proximally and distally. Supportive care, given during EBRT includes an antifungal agent (e.g., diflucan) and carafate. Gradual dilatation of the esophagus is required post-treatment for esophageal strictures. Conclusion: Guidelines were developed for brachytherapy in esophageal cancer. As more clinical data becomes available, these guidelines will be updated by the ABS

  13. Local anesthesia for prostate brachytherapy

    International Nuclear Information System (INIS)

    Wallner, Kent; Simpson, Colleen; Roof, James; Arthurs, Sandy; Korssjoen, Tammy; Sutlief, Steven

    1999-01-01

    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. Specification of brachytherapy sources

    Energy Technology Data Exchange (ETDEWEB)

    1984-10-01

    BCRU recommends that the following specification of gamma-ray brachytherapy sources be adopted. Unless otherwise stated, the output of a cylindrical source should be specified in air kerma rate at a point in free space at a distance of 1 m from the source on the radial plane of symmetry, i.e. the plane bisecting the active length and perpendicular to the cylindrical axis of the source. For a wire source the output should be specified for a 1 cm length. For any other construction of source, the point at which the output is specified should be stated. It is also recommended that the units in which the air kerma rate is expressed should be micrograys per hour (..mu..Gy/h).

  15. Importance of brachytherapy technique in the management of primary carcinoma of the vagina

    International Nuclear Information System (INIS)

    Stock, R.G.; Mychalczak, B.; Armstrong, J.G.; Hoskins, W.; Harrison, L.B.

    1991-01-01

    Primary vaginal carcinoma is a rare malignancy. There is little information regarding the optimal treatment. Management has primarily been with external-beam radiation therapy and brachytherapy. This paper examines the importance of brachytherapy and the significance of its techniques in the treatment of this disease. Brachytherapy plays an important part in the management of primary vaginal carcinoma. External-beam radiation therapy alone is not an adequate treatment for this disease. For stages II and III disease, there is a trend toward improved disease-free survival with the use of a temporary interstitial implant compared to an intracavitary application

  16. Radiotherapy and brachytherapy

    International Nuclear Information System (INIS)

    2007-02-01

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

  17. 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)

  18. A D-Shaped Bileaflet Bioprosthesis which Replicates Physiological Left Ventricular Flow Patterns.

    Directory of Open Access Journals (Sweden)

    Sean Guo-Dong Tan

    Full Text Available Prior studies have shown that in a healthy heart, there exist a large asymmetric vortex structure that aids in establishing a steady flow field in the left ventricle. However, the implantation of existing artificial heart valves at the mitral position is found to have a negative effect on this physiological flow pattern. In light of this, a novel D-shaped bileaflet porcine bioprosthesis (GD valve has been designed based on the native geometry mitral valve, with the hypothesis that biomimicry in valve design can restore physiological left ventricle flow patterns after valve implantation. An in-vitro experiment using two dimensional particle velocimetry imaging was carried out to determine the hemodynamic performance of the new bileaflet design and then compared to that of the well-established St. Jude Epic valve which functioned as a control in the experiment. Although both valves were found to have similar Reynolds shear stress and Turbulent Kinetic Energy levels, the novel D-shape valve was found to have lower turbulence intensity and greater mean kinetic energy conservation.

  19. A D-Shaped Bileaflet Bioprosthesis which Replicates Physiological Left Ventricular Flow Patterns

    Science.gov (United States)

    Tan, Sean Guo-Dong; Kim, Sangho; Hon, Jimmy Kim Fatt; Leo, Hwa Liang

    2016-01-01

    Prior studies have shown that in a healthy heart, there exist a large asymmetric vortex structure that aids in establishing a steady flow field in the left ventricle. However, the implantation of existing artificial heart valves at the mitral position is found to have a negative effect on this physiological flow pattern. In light of this, a novel D-shaped bileaflet porcine bioprosthesis (GD valve) has been designed based on the native geometry mitral valve, with the hypothesis that biomimicry in valve design can restore physiological left ventricle flow patterns after valve implantation. An in-vitro experiment using two dimensional particle velocimetry imaging was carried out to determine the hemodynamic performance of the new bileaflet design and then compared to that of the well-established St. Jude Epic valve which functioned as a control in the experiment. Although both valves were found to have similar Reynolds shear stress and Turbulent Kinetic Energy levels, the novel D-shape valve was found to have lower turbulence intensity and greater mean kinetic energy conservation. PMID:27258099

  20. 3D shape measurements with a single interferometric sensor for in-situ lathe monitoring

    Science.gov (United States)

    Kuschmierz, R.; Huang, Y.; Czarske, J.; Metschke, S.; Löffler, F.; Fischer, A.

    2015-05-01

    Temperature drifts, tool deterioration, unknown vibrations as well as spindle play are major effects which decrease the achievable precision of computerized numerically controlled (CNC) lathes and lead to shape deviations between the processed work pieces. Since currently no measurement system exist for fast, precise and in-situ 3d shape monitoring with keyhole access, much effort has to be made to simulate and compensate these effects. Therefore we introduce an optical interferometric sensor for absolute 3d shape measurements, which was integrated into a working lathe. According to the spindle rotational speed, a measurement rate of 2,500 Hz was achieved. In-situ absolute shape, surface profile and vibration measurements are presented. While thermal drifts of the sensor led to errors of several mµm for the absolute shape, reference measurements with a coordinate machine show, that the surface profile could be measured with an uncertainty below one micron. Additionally, the spindle play of 0.8 µm was measured with the sensor.

  1. Comparison On Matching Methods Used In Pose Tracking For 3D Shape Representation

    Directory of Open Access Journals (Sweden)

    Khin Kyu Kyu Win

    2017-01-01

    Full Text Available In this work three different algorithms such as Brute Force Delaunay Triangulation and k-d Tree are analyzed on matching comparison for 3D shape representation. It is intended for developing the pose tracking of moving objects in video surveillance. To determine 3D pose of moving objects some tracking system may require full 3D pose estimation of arbitrarily shaped objects in real time. In order to perform 3D pose estimation in real time each step in the tracking algorithm must be computationally efficient. This paper presents method comparison for the computationally efficient registration of 3D shapes including free-form surfaces. Matching of free-form surfaces are carried out by using geometric point matching algorithm ICP. Several aspects of the ICP algorithm are investigated and analyzed by using specified surface setup. The surface setup processed in this system is represented by simple geometric primitive dealing with objects of free-from shape. Considered representations are a cloud of points.

  2. Should the bladder be full or empty during gynecologic brachytherapy applications? A bladder dose volume histogram analysis and implications for treatment

    International Nuclear Information System (INIS)

    Dusenbery, Kathryn E.; Lewandowski, Loretta A.; Higgins, Patrick D.

    1996-01-01

    Purpose: Chronic radiation cystitis is an uncommon but debilitating late complication of definitive external beam (EB) and brachytherapy (BT) for cervix cancer. During BT an indwelling catheter is usually placed in the bladder, collapsing it closer to the BT sources. We have devised a method to deliver BT with a full bladder. The difference in bladder dose in the full and empty state were analyzed during definitive EBT and BT for cervix cancer. Methods: The technique of Lyman and Wolbarst (1) were used to evaluate the bladder complication probability for a representative cervix cancer patient undergoing EBT and BT. DVHs were generated from CT scans obtained with a full and empty bladder. Three possible dose prescriptions were analyzed. Results: The DVH for the full and empty situations are shown. With the bladder full, the volume of bladder predicted to receive ≥ 80 Gy was approximately 10% for all dose schemes evaluated, whereas with the bladder empty, up to 50% of the bladder volume received ≥ 80 Gy. Conclusions: A distended bladder improves the DVH. A technique for performing full bladder LDR brachytherapy will be discussed

  3. Novel treatment options for nonmelanoma skin cancer: focus on electronic brachytherapy

    Directory of Open Access Journals (Sweden)

    Kasper ME

    2015-11-01

    Full Text Available Michael E Kasper,1,2 Ahmed A Chaudhary3 1Department of Radiation Oncology, Lynn Cancer Institute at Boca Raton Regional Hospital, Boca Raton, 2Charles E. Schmidt College of Medicine, Florida Atlantic University, FL, 3North Main Radiation Oncology, Warren Alpert School of Medicine, Brown University, RI, USA Abstract: Nonmelanoma skin cancer (NMSC is an increasing health care issue in the United States, significantly affecting quality of life and impacting health care costs. Radiotherapy has a long history in the treatment of NMSC. Shortly after the discovery of X-rays and 226Radium, physicians cured patients with NMSC using these new treatments. Both X-ray therapy and brachytherapy have evolved over the years, ultimately delivering higher cure rates and lower toxicity. Electronic brachytherapy for NMSC is based on the technical and clinical data obtained from radionuclide skin surface brachytherapy and the small skin surface applicators developed over the past 25 years. The purpose of this review is to introduce electronic brachytherapy in the context of the history, data, and utilization of traditional radiotherapy and brachytherapy. Keywords: electronic brachytherapy, superficial radiotherapy, skin surface brachytherapy, electron beam therapy, nonmelanoma skin cancer, basal cell carcinoma, squamous cell carcinoma

  4. A study on the accuracy of source position in HDR brachytherapy according to the curvature of universal application transfer tube and applicator type

    International Nuclear Information System (INIS)

    Shin, Hyeon Kyung; Lee, Sang Kyoo; Kim, Joo Ho; Cho, Jeong Hee

    2015-01-01

    The goal of this study was to verify and analyze the source position according to the curvature of the universal applicator and 4 different angle applicators when using RALS(Remote After Loading System). An interval of 1 cm and 15 second dwell times in each source position were applied for plan. To verify the accuracy of source position, we narrowed the distance between MultiSource container and GAFCHROMIC? EBT3 film by 5 cm, 10 cm, 20 cm so that the universal applicator transfer tube had some curvature. Also 4 applicators(Intrauterine tube: 0° , 15°, 30° , Ovoid tube: 65° ) were used in the same condition. The differences between desired and actual source position were measured by using Image J. In case of using 4 different angles of applicator with the straight universal applicator transfer tube, the average error was the lowest for 0°applicator, greatest for 65°applicator. However, All average errors were within ±2 mm recommended in TG-56. When MultiSource container was moved 5 cm, 10 cm, 20 cm towards the EBT3 film, the average errors were beyond ±2 mm. The first dwell position was relatively located in accuracy, while the second and third dwells were displaced by an increasing magnitude with increasing curvature of the transfer tube. Furthermore, with increasing the angle of applicators, the error of all other dwell positioning was increased. The results of this study showed that both the curvature of universal applicator transfer tube and the angle of applicators affect the source dwell position. It is recommended that using straight universal applicator transfer tubes is followed in all cases, in order to avoid deviations in the delivered source dwell position. Also, It is advisable to verify the actual dwell position, using video camera quality control tool prior to all treatments

  5. Erectile function after prostate brachytherapy

    International Nuclear Information System (INIS)

    Merrick, Gregory S.; Butler, Wayne M.; Wallner, Kent E.; Galbreath, Robert W.; Anderson, Richard L.; Kurko, Brian S.; Lief, Jonathan H.; Allen, Zachariah A.

    2005-01-01

    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 (V 100/150/200 ); the dose delivered to 90% of the prostate gland (D 90 ); 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

  6. Experiences with alanine dosimetry in afterloading brachytherapy

    International Nuclear Information System (INIS)

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

    1996-01-01

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

  7. Micro Fourier Transform Profilometry (μFTP): 3D shape measurement at 10,000 frames per second

    Science.gov (United States)

    Zuo, Chao; Tao, Tianyang; Feng, Shijie; Huang, Lei; Asundi, Anand; Chen, Qian

    2018-03-01

    Fringe projection profilometry is a well-established technique for optical 3D shape measurement. However, in many applications, it is desirable to make 3D measurements at very high speed, especially with fast moving or shape changing objects. In this work, we demonstrate a new 3D dynamic imaging technique, Micro Fourier Transform Profilometry (μFTP), which can realize an acquisition rate up to 10,000 3D frame per second (fps). The high measurement speed is achieved by the number of patterns reduction as well as high-speed fringe projection hardware. In order to capture 3D information in such a short period of time, we focus on the improvement of the phase recovery, phase unwrapping, and error compensation algorithms, allowing to reconstruct an accurate, unambiguous, and distortion-free 3D point cloud with every two projected patterns. We also develop a high-frame-rate fringe projection hardware by pairing a high-speed camera and a DLP projector, enabling binary pattern switching and precisely synchronized image capture at a frame rate up to 20,000 fps. Based on this system, we demonstrate high-quality textured 3D imaging of 4 transient scenes: vibrating cantilevers, rotating fan blades, flying bullet, and bursting balloon, which were previously difficult or even unable to be captured with conventional approaches.

  8. Ultrasensitive Mach-Zehnder Interferometric Temperature Sensor Based on Liquid-Filled D-Shaped Fiber Cavity

    Directory of Open Access Journals (Sweden)

    Hui Zhang

    2018-04-01

    Full Text Available A liquid-filled D-shaped fiber (DF cavity serving as an in-fiber Mach–Zehnder interferometer (MZI has been proposed and experimentally demonstrated for temperature sensing with ultrahigh sensitivity. The miniature MZI is constructed by splicing a segment of DF between two single-mode fibers (SMFs to form a microcavity (MC for filling and replacement of various refractive index (RI liquids. By adjusting the effective RI difference between the DF and MC (the two interference arms, experimental and calculated results indicate that the interference spectra show different degrees of temperature dependence. As the effective RI of the liquid-filled MC approaches that of the DF, temperature sensitivity up to −84.72 nm/°C with a linear correlation coefficient of 0.9953 has been experimentally achieved for a device with the MC length of 456 μm, filled with liquid RI of 1.482. Apart from ultrahigh sensitivity, the proposed MCMZI device possesses additional advantages of its miniature size and simple configuration; these features make it promising and competitive in various temperature sensing applications, such as consumer electronics, biological treatments, and medical diagnosis.

  9. Ultrasensitive Mach-Zehnder Interferometric Temperature Sensor Based on Liquid-Filled D-Shaped Fiber Cavity.

    Science.gov (United States)

    Zhang, Hui; Gao, Shecheng; Luo, Yunhan; Chen, Zhenshi; Xiong, Songsong; Wan, Lei; Huang, Xincheng; Huang, Bingsen; Feng, Yuanhua; He, Miao; Liu, Weiping; Chen, Zhe; Li, Zhaohui

    2018-04-17

    A liquid-filled D-shaped fiber (DF) cavity serving as an in-fiber Mach–Zehnder interferometer (MZI) has been proposed and experimentally demonstrated for temperature sensing with ultrahigh sensitivity. The miniature MZI is constructed by splicing a segment of DF between two single-mode fibers (SMFs) to form a microcavity (MC) for filling and replacement of various refractive index (RI) liquids. By adjusting the effective RI difference between the DF and MC (the two interference arms), experimental and calculated results indicate that the interference spectra show different degrees of temperature dependence. As the effective RI of the liquid-filled MC approaches that of the DF, temperature sensitivity up to −84.72 nm/°C with a linear correlation coefficient of 0.9953 has been experimentally achieved for a device with the MC length of 456 μm, filled with liquid RI of 1.482. Apart from ultrahigh sensitivity, the proposed MCMZI device possesses additional advantages of its miniature size and simple configuration; these features make it promising and competitive in various temperature sensing applications, such as consumer electronics, biological treatments, and medical diagnosis.

  10. Optical Estimation of the 3D Shape of a Solar Illuminated, Reflecting Satellite Surface

    Science.gov (United States)

    Antolin, J.; Yu, Z.; Prasad, S.

    2016-09-01

    The spatial distribution of the polarized component of the power reflected by a macroscopically smooth but microscopically roughened curved surface under highly directional illumination, as characterized by an appropriate bi-directional reflectance distribution function (BRDF), carries information about the three-dimensional (3D) shape of the surface. This information can be exploited to recover the surface shape locally under rather general conditions whenever power reflectance data for at least two different illumination or observation directions can be obtained. We present here two different parametric approaches for surface reconstruction, amounting to the recovery of the surface parameters that are either the global parameters of the family to which the surface is known a priori to belong or the coefficients of a low-order polynomial that can be employed to characterize a smoothly varying surface locally over the observed patch.

  11. The hazy dawn of brachytherapy

    International Nuclear Information System (INIS)

    Dutreix, J.; Tubiana, M.; Pierquin, B.

    1998-01-01

    The discovery of radium by Pierre and Marie Curie in December 1898 opened a new era in science and within a few years provided medicine with a new means of tumor treatment. Their personal contribution to the start and early development of clinical applications should not be overlooked. The Curies did not limit their support to providing radium sources to medical pioneers but took a deep interest in the horizons of radiumtherapy. Pierre was one of the first to search for and demonstrate a biological effect of radium radiation. He investigated the radioactivity of the waters of hydrotherapeutic resorts. Marie took care of the measurement of the medical sources personally, convinced that the result of the treatment depends on the precise knowledge of the amount of radium applied. Her perseverance resulted in the establishment of the Institut du Radium (1909) in which, besides the physico-chemical laboratory, a biological department was set up. The latter became the Fondation Curie (1920), a leading medical center of treatment and training, with an integrated team of physicists, radiobiologists and clinicians led by Regaud. One hundred years after the discovery of radium, patients benefit today from the extensive clinical experience that has been collected over the years and from sophisticated developments in application techniques, dosimetry and quality assurance; the professional risk has been precisely assessed and the improvements in material and procedure have enabled the medical personnel to work in hazard-free conditions. This outcome results from the continuous progress that the pioneers gave impulse to. This paper intends to recall their efforts and achievements, as well as the difficulties and the problems they encountered during the first 2 decades when the sturdy foundations of brachytherapy were built. (Copyright (c) 1998 Elsevier Science B.V., Amsterdam. All rights reserved.)

  12. 3D shape recovery of a newborn skull using thin-plate splines.

    Science.gov (United States)

    Lapeer, R J; Prager, R W

    2000-01-01

    The objective of this paper is to construct a mesh-model of a newborn skull for finite element analysis to study its deformation when subjected to the forces present during labour. The current state of medical imaging technology has reached a level which allows accurate visualisation and shape recovery of biological organs and body-parts. However, a sufficiently large set of medical images cannot always be obtained, often because of practical or ethical reasons, and the requirement to recover the shape of the biological object of interest has to be met by other means. Such is the case for a newborn skull. A method to recover the three-dimensional (3D) shape from (minimum) two orthogonal atlas images of the object of interest and a homologous object is described. This method is based on matching landmarks and curves on the orthogonal images of the object of interest with corresponding landmarks and curves on the homologous or 'master'-object which is fully defined in 3D space. On the basis of this set of corresponding landmarks, a thin-plate spline function can be derived to warp from the 'master'-object space to the 'slave'-object space. This method is applied to recover the 3D shape of a newborn skull. Images from orthogonal view-planes are obtained from an atlas. The homologous object is an adult skull, obtained from CT-images made available by the Visible Human Project. After shape recovery, a mesh-model of the newborn skull is generated.

  13. Quantitative model for the generic 3D shape of ICMEs at 1 AU

    Science.gov (United States)

    Démoulin, P.; Janvier, M.; Masías-Meza, J. J.; Dasso, S.

    2016-10-01

    Context. Interplanetary imagers provide 2D projected views of the densest plasma parts of interplanetary coronal mass ejections (ICMEs), while in situ measurements provide magnetic field and plasma parameter measurements along the spacecraft trajectory, that is, along a 1D cut. The data therefore only give a partial view of the 3D structures of ICMEs. Aims: By studying a large number of ICMEs, crossed at different distances from their apex, we develop statistical methods to obtain a quantitative generic 3D shape of ICMEs. Methods: In a first approach we theoretically obtained the expected statistical distribution of the shock-normal orientation from assuming simple models of 3D shock shapes, including distorted profiles, and compared their compatibility with observed distributions. In a second approach we used the shock normal and the flux rope axis orientations together with the impact parameter to provide statistical information across the spacecraft trajectory. Results: The study of different 3D shock models shows that the observations are compatible with a shock that is symmetric around the Sun-apex line as well as with an asymmetry up to an aspect ratio of around 3. Moreover, flat or dipped shock surfaces near their apex can only be rare cases. Next, the sheath thickness and the ICME velocity have no global trend along the ICME front. Finally, regrouping all these new results and those of our previous articles, we provide a quantitative ICME generic 3D shape, including the global shape of the shock, the sheath, and the flux rope. Conclusions: The obtained quantitative generic ICME shape will have implications for several aims. For example, it constrains the output of typical ICME numerical simulations. It is also a base for studying the transport of high-energy solar and cosmic particles during an ICME propagation as well as for modeling and forecasting space weather conditions near Earth.

  14. 3D shape measurement of automotive glass by using a fringe reflection technique

    Science.gov (United States)

    Skydan, O. A.; Lalor, M. J.; Burton, D. R.

    2007-01-01

    In automotive and glass making industries, there is a need for accurately measuring the 3D shapes of reflective surfaces to speed up and ensure product development and manufacturing quality by using non-contact techniques. This paper describes a technique for the measurement of non-full-field reflective surfaces of automotive glass by using a fringe reflection technique. Physical properties of the measurement surfaces do not allow us to apply optical geometries used in existing techniques for surface measurement based upon direct fringe pattern illumination. However, this property of surface reflectivity can be used to implement similar ideas from existing techniques in a new improved method. In other words, the reflective surface can be used as a mirror to reflect illuminated fringe patterns onto a screen behind. It has been found that in the case of implementing the reflective fringe technique, the phase-shift distribution depends not only on the height of the object but also on the slope at each measurement point. This requires the solving of differential equations to find the surface slope and height distributions in the x and y directions and development of the additional height reconstruction algorithms. The main focus has been made on developing a mathematical model of the optical sub-system and discussing ways for its practical implementation including calibration procedures. A number of implemented image processing algorithms for system calibration and data analysis are discussed and two experimental results are given for automotive glass surfaces with different shapes and defects. The proposed technique showed the ability to provide accurate non-destructive measurement of 3D shapes of the reflective automotive glass surfaces and can be used as a key element for a glass shape quality control system on-line or in a laboratory environment.

  15. Biology of dose rate in brachytherapy

    International Nuclear Information System (INIS)

    Brenner, David J.

    1995-01-01

    Purpose: This course is designed for practitioners and beginners in brachytherapy. The aim is to review biological principles underlying brachytherapy, to understand why current treatment regimes are the way they are, and to discuss what the future may hold in store. Brachytherapy has a long history. It was suggested as long ago as 1903 by Alexander Graham Bell, and the optimal application of this technique has been a subject of debate ever since. 'Brachy' means 'short', and the essential features of conventional brachytherapy are: positioning of the source a short distance from, or in, the tumor, allowing good dose distributions; short overall treatment times, to counter tumor repopulation; low dose rate, enabling a good therapeutic advantage between tumor control and damage to late-responding tissue. The advantages of good dose distributions speak for themselves; in some situations, as we shall see, computer-based dose optimization can be used to improve them still further. The advantages of short overall times stem from the fact that accelerated repopulation of the tumor typically begins a few weeks after the start of a radiation treatment. If all the radiation can be crammed in before that time, the risks of tumor repopulation can be considerably reduced. In fact even external-beam radiotherapy is moving in this direction, with the use of highly accelerated protocols. The advantages of low dose rate stem from the differential response to fractionation of early- and late-responding tissues. Essentially, lowering the dose rate spares late-responding tissue more than it does early-responding tissue such as tumors. We shall also discuss some recent innovations in the context of the general principles that have been outlined. For example, High dose rate brachytherapy, particularly for the uterine cervix: Does it work? If so, when and why? Use of Ir-192 sources, with a half life of 70 days: Should corrections be made for changing biological effectiveness as the dose

  16. Comparison of different treatment planning optimization methods for vaginal HDR brachytherapy with multichannel applicators: A reduction of the high doses to the vaginal mucosa is possible.

    Science.gov (United States)

    Carrara, Mauro; Cusumano, Davide; Giandini, Tommaso; Tenconi, Chiara; Mazzarella, Ester; Grisotto, Simone; Massari, Eleonora; Mazzeo, Davide; Cerrotta, Annamaria; Pappalardi, Brigida; Fallai, Carlo; Pignoli, Emanuele

    2017-12-01

    A direct planning approach with multi-channel vaginal cylinders (MVCs) used for HDR brachytherapy of vaginal cancers is particularly challenging. Purpose of this study was to compare the dosimetric performances of different forward and inverse methods used for the optimization of MVC-based vaginal treatments for endometrial cancer, with a particular attention to the definition of strategies useful to limit the high doses to the vaginal mucosa. Twelve postoperative vaginal HDR brachytherapy treatments performed with MVCs were considered. Plans were retrospectively optimized with three different methods: Dose Point Optimization followed by Graphical Optimization (DPO + GrO), Inverse Planning Simulated Annealing with two different class solutions as starting conditions (surflPSA and homogIPSA) and Hybrid Inverse Planning Optimization (HIPO). Several dosimetric parameters related to target coverage, hot spot extensions and sparing of organs at risk were analyzed to evaluate the quality of the achieved treatment plans. Dose homogeneity index (DHI), conformal index (COIN) and a further parameter quantifying the proportion of the central catheter loading with respect to the overall loading (i.e., the central catheter loading index: CCLI) were also quantified. The achieved PTV coverage parameters were highly correlated with each other but uncorrelated with the hot spot quantifiers. HomogIPSA and HIPO achieved higher DHIs and CCLIs and lower volumes of high doses than DPO + GrO and surflPSA. Within the investigated optimization methods, HIPO and homoglPSA showed the highest dose homogeneity to the target. In particular, homogIPSA resulted also the most effective in reducing hot spots to the vaginal mucosa. Copyright © 2017 Associazione Italiana di Fisica Medica. Published by Elsevier Ltd. All rights reserved.

  17. Clinical application and validation of an iterative forward projection matching algorithm for permanent brachytherapy seed localization from conebeam-CT x-ray projections

    Energy Technology Data Exchange (ETDEWEB)

    Pokhrel, Damodar; Murphy, Martin J.; Todor, Dorin A.; Weiss, Elisabeth; Williamson, Jeffrey F. [Department of Radiation Oncology, School of Medicine, Virginia Commonwealth University, Richmond, Virginia 23298 (United States)

    2010-09-15

    Purpose: To experimentally validate a new algorithm for reconstructing the 3D positions of implanted brachytherapy seeds from postoperatively acquired 2D conebeam-CT (CBCT) projection images. Methods: The iterative forward projection matching (IFPM) algorithm finds the 3D seed geometry that minimizes the sum of the squared intensity differences between computed projections of an initial estimate of the seed configuration and radiographic projections of the implant. In-house machined phantoms, containing arrays of 12 and 72 seeds, respectively, are used to validate this method. Also, four {sup 103}Pd postimplant patients are scanned using an ACUITY digital simulator. Three to ten x-ray images are selected from the CBCT projection set and processed to create binary seed-only images. To quantify IFPM accuracy, the reconstructed seed positions are forward projected and overlaid on the measured seed images to find the nearest-neighbor distance between measured and computed seed positions for each image pair. Also, the estimated 3D seed coordinates are compared to known seed positions in the phantom and clinically obtained VariSeed planning coordinates for the patient data. Results: For the phantom study, seed localization error is (0.58{+-}0.33) mm. For all four patient cases, the mean registration error is better than 1 mm while compared against the measured seed projections. IFPM converges in 20-28 iterations, with a computation time of about 1.9-2.8 min/iteration on a 1 GHz processor. Conclusions: The IFPM algorithm avoids the need to match corresponding seeds in each projection as required by standard back-projection methods. The authors' results demonstrate {approx}1 mm accuracy in reconstructing the 3D positions of brachytherapy seeds from the measured 2D projections. This algorithm also successfully localizes overlapping clustered and highly migrated seeds in the implant.

  18. Clinical application and validation of an iterative forward projection matching algorithm for permanent brachytherapy seed localization from conebeam-CT x-ray projections.

    Science.gov (United States)

    Pokhrel, Damodar; Murphy, Martin J; Todor, Dorin A; Weiss, Elisabeth; Williamson, Jeffrey F

    2010-09-01

    To experimentally validate a new algorithm for reconstructing the 3D positions of implanted brachytherapy seeds from postoperatively acquired 2D conebeam-CT (CBCT) projection images. The iterative forward projection matching (IFPM) algorithm finds the 3D seed geometry that minimizes the sum of the squared intensity differences between computed projections of an initial estimate of the seed configuration and radiographic projections of the implant. In-house machined phantoms, containing arrays of 12 and 72 seeds, respectively, are used to validate this method. Also, four 103Pd postimplant patients are scanned using an ACUITY digital simulator. Three to ten x-ray images are selected from the CBCT projection set and processed to create binary seed-only images. To quantify IFPM accuracy, the reconstructed seed positions are forward projected and overlaid on the measured seed images to find the nearest-neighbor distance between measured and computed seed positions for each image pair. Also, the estimated 3D seed coordinates are compared to known seed positions in the phantom and clinically obtained VariSeed planning coordinates for the patient data. For the phantom study, seed localization error is (0.58 +/- 0.33) mm. For all four patient cases, the mean registration error is better than 1 mm while compared against the measured seed projections. IFPM converges in 20-28 iterations, with a computation time of about 1.9-2.8 min/ iteration on a 1 GHz processor. The IFPM algorithm avoids the need to match corresponding seeds in each projection as required by standard back-projection methods. The authors' results demonstrate approximately 1 mm accuracy in reconstructing the 3D positions of brachytherapy seeds from the measured 2D projections. This algorithm also successfully localizes overlapping clustered and highly migrated seeds in the implant.

  19. Pulsed dose rate brachytherapy – is it the right way?

    Directory of Open Access Journals (Sweden)

    Janusz Skowronek

    2010-10-01

    Full Text Available Pulsed dose rate (PDR-BT treatment is a brachytherapy modality that combines physical advantages of high-doserate (HDR-BT technology (isodose optimization, radiation safety with the radiobiological advantages of low-dose-rate (LDR-BT brachytherapy. Pulsed brachytherapy consists of using stronger radiation source than for LDR-BT and producing series of short exposures of 10 to 30 minutes in every hour to approximately the same total dose in the sameoverall time as with the LDR-BT. Modern afterloading equipment offers certain advantages over interstitial or intracavitaryinsertion of separate needles, tubes, seeds or wires. Isodose volumes in tissues can be created flexibly by a combinationof careful placement of the catheter and the adjustment of the dwell times of the computerized stepping source.Automatic removal of the radiation sources into a shielded safe eliminates radiation exposures to staff and visitors.Radiation exposure is also eliminated to the staff who formerly loaded and unloaded multiplicity of radioactive sources into the catheters, ovoids, tubes etc. This review based on summarized clinical investigations, analyses the feasibility and the background to introduce this brachytherapy technique and chosen clinical applications of PDR-BT.

  20. Brachytherapy in Europe: philosophies, current practice and future directions

    International Nuclear Information System (INIS)

    Haworth, A.

    2000-01-01

    Full text: Five months sabbatical leave provided an opportunity to visit six radiotherapy centres in France, Holland and England. While brachytherapy philosophies and practices within each country were similar, there were considerable differences in attitudes between countries. The Institute Gustave Roussy, home of the Paris System and host for the French sector confirmed that the Paris System is still very much the preferred dosimetry method in this part of the world. Though their preference for low dose rate brachytherapy is still evident, high dose rate brachytherapy has found some applications but the rules of the Paris System are never far away and the words 'what about the hyperdose sleeve' are firmly implanted into this visitor's brain. The use of real time dosimetry for I-125 prostate brachytherapy at the Institute Curie (Paris) provided an interesting contrast to the standard pre and post implant dosimetry techniques commonly employed elsewhere. The two Dutch centres on the itinerary, in stark contrast to the traditional techniques seen in France, have applied the power of computers to investigate optimisation of the classic dosimetry systems and called on the analysis techniques (DVH, NTCP, TCP etc) now familiar to us all in external beam therapy. The Cookridge Hospital in England fitted somewhere between the French and Dutch centres. This centre showed how both modern and traditional techniques could be applied in an efficient way for a large variety of treatment sites. Copyright (2000) Australasian College of Physical Scientists and Engineers in Medicine

  1. Comparison between Japanese and French interstitial brachytherapy for head and neck cancer

    International Nuclear Information System (INIS)

    Nose, Takayuki; Koizumi, Masahiko; Nishiyama, Kinji; Inoue, Toshihiko

    2001-01-01

    Interstitial brachytherapy is the optimal radiotherapy modality for head and neck cancer because the highest dose conformity can be achieved, and implanted tubes can move synchronously with the tumor movement. Compared with radical surgery, interstitial brachytherapy can achieve equivalent local control with less morbidity and less functional deficit. In Japan, because of technical limitations, interstitial brachytherapy has been confined to treatment of small tongue cancers. To improve our head and neck cancer treatment, technical limitations should be eliminated and a wider indication for interstitial brachytherapy should be achieved. In France, interstitial brachytherapy has been technically more developed and widely indicated than in Japan. We analyzed the differences between Japanese (Osaka) and French (Lyon and Nancy) techniques, to improve our interstitial brachytherapy. Implant devices and techniques: French applicators (Longcip 1) are more flexible and more suitable for loop techniques of the soft palate, the base of the tongue, and the vallecula, than applicators available in Japan. Various implant techniques are established especially for the oropharynx in France. Mandibular protection: Lead blocks used in France can more effectively shield the mandible than our silicone spacers. We showed the dosimetric results in an experimental treatment setting. Dose specification: The five-mm dose specification method used in Japan can work only for easy cases, such as small oral tongue cancers and mouth floor cancers. For complicated implants, such as for the oropharynx, the CTV-based dose specification method used in France is essential for sufficient irradiation. Indications: The indication for head and neck interstitial brachytherapy in Japan is limited mostly to small oral tongue cancers. The indication in France is wider, including the oral cavity, the oropharynx, and postoperative cases. We can refine our head and neck cancer treatment if we combine French

  2. Relative humidity sensor based on surface plasmon resonance of D-shaped fiber with polyvinyl alcohol embedding Au grating

    Science.gov (United States)

    Yan, Haitao; Han, Daofu; Li, Ming; Lin, Bo

    2017-01-01

    This paper presents the design, fabrication, and characterization of a D-shaped fiber coated with polyvinyl alcohol (PVA) embedding an Au grating-based relative humidity (RH) sensor. The Au grating is fabricated on a D-shaped fiber to match the wave-vector and excite the surface plasmon, and the PVA is embedded in the Au grating as a sensitive cladding film. The refractive index of PVA changes with the ambient humidity. Measurements in a controlled environment show that the RH sensor can achieve a sensitivity of 5.4 nm per relative humidity unit in the RH range from 0% to 70% RH. Moreover, the surface plasmon resonance can be realized and used for RH sensing at the C band of optical fiber communication instead of the visible light band due to the metallic grating microstructure on the D-shaped fiber.

  3. Dosimetry in intravascular brachytherapy

    International Nuclear Information System (INIS)

    Campos, Laelia Pumilla Botelho

    2000-03-01

    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)

  4. Inverse planning and class solutions for brachytherapy treatment planning

    International Nuclear Information System (INIS)

    Trnkova, P.

    2010-01-01

    has no additional features how to control spatial distribution of high dose regions. It is possible to create a dosimetrically acceptable treatment plans with IPSA. Nevertheless, the size of high dose regions is not acceptable. In comparison to manual treatment planning as well as to HIPO optimization, IPSA lead to the conflicting results concerning high dose regions. To be able to use IPSA for inverse treatment planning in cervical cancer brachytherapy additional tools have to be developed. The last part of the thesis is engaged with vaginal wall dosimetry. Dose volume constraints for target volume as well as for organs OARs are an input for inverse planning optimization calculation. A dose tolerance of each OAR has to be known to be able to create appropriate constraints. Until now only bladder, rectum and sigmoid were considered as OARs. The dose limits for vagina don't exist yet because of several uncertainties during assessing of dose to the vagina and vaginal morbidity. To overcome contouring uncertainties a simplified vagina contour was proposed and tested. The analysis showed that this contour is able to detect differences between different applicators as well as between different treatment plans. A prospective study comparing dosimetric results of this model and side effects in the vagina has to be done to prove whether this contour is working or not. In conclusion, this thesis proved that inverse planning can be used for cervical cancer brachytherapy. An appropriate implementation of the inverse planning algorithm has to be considered to avoid high dose regions. Prior including of a dose volume constrains of vagina as another input parameter for the inverse planning calculation vaginal dose reporting has to be solved. The feasibility of the proposed simplified vagina contour for dose reporting has to be proven with a prospective study. (author) [de

  5. Quantification of lacrimal function after D-shaped field irradiation for retinoblastoma

    International Nuclear Information System (INIS)

    Imhof, S.M.; Tan, K.E.W.P.; Hofman, P.

    1993-01-01

    To study the quantitative effects of mega-voltage external beam irradiation in a D-shaped field in patients with retinoblastoma, biomicroscopy was performed in 61 patients and tear function tests (Schirmer-lactoferrin and lysozyme tests) on 45 eyes in 34 irradiated patients. The results were compared with those obtained in 25 non-irradiated control eyes. The Schirmer test was significantly diminished in irradiated eyes, as were the lactoferrin and lysozyme values. A mild to severe keratitis was found in 17 of the 61 patients (28%). A significant correlation (p<0.005) was found between the severe keratitis and the mean Schirmer values; the mean lactoferrin and lysozyme values were diminished in all patients but did not correlate significantly with the corneal abnormalities. These quantitative data, obtained in patients treated for retinoblastoma, affirm the qualitative data found in patients irradiated for other reasons such as orbital or sinus tumours. Irradiation for retinoblastoma is not a harmless treatment and serious late side effects have to be considered. (Author)

  6. Memory color of natural familiar objects: effects of surface texture and 3-D shape.

    Science.gov (United States)

    Vurro, Milena; Ling, Yazhu; Hurlbert, Anya C

    2013-06-28

    Natural objects typically possess characteristic contours, chromatic surface textures, and three-dimensional shapes. These diagnostic features aid object recognition, as does memory color, the color most associated in memory with a particular object. Here we aim to determine whether polychromatic surface texture, 3-D shape, and contour diagnosticity improve memory color for familiar objects, separately and in combination. We use solid three-dimensional familiar objects rendered with their natural texture, which participants adjust in real time to match their memory color for the object. We analyze mean, accuracy, and precision of the memory color settings relative to the natural color of the objects under the same conditions. We find that in all conditions, memory colors deviate slightly but significantly in the same direction from the natural color. Surface polychromaticity, shape diagnosticity, and three dimensionality each improve memory color accuracy, relative to uniformly colored, generic, or two-dimensional shapes, respectively. Shape diagnosticity improves the precision of memory color also, and there is a trend for polychromaticity to do so as well. Differently from other studies, we find that the object contour alone also improves memory color. Thus, enhancing the naturalness of the stimulus, in terms of either surface or shape properties, enhances the accuracy and precision of memory color. The results support the hypothesis that memory color representations are polychromatic and are synergistically linked with diagnostic shape representations.

  7. Research on High Sensitive D-Shaped FBG Hydrogen Sensors in Power Transformer Oil.

    Science.gov (United States)

    Luo, Ying-Ting; Wang, Hong-Bin; Ma, Guo-Ming; Song, Hong-Tu; Li, Chengrong; Jiang, Jun

    2016-10-04

    Dissolved hydrogen is a symbol gas decomposed by power transformer oil for electrical faults such as overheat or partial discharges. A novel D-shaped fiber Bragg grating (D-FBG) sensor is herein proposed and was fabricated with magnetron sputtering to measure the dissolved hydrogen concentration in power transformer oil in this paper. Different from the RI (refractive index)-based effect, D-FBG in this case is sensitive to curvature caused by stress from sensing coating, leading to Bragg wavelength shifts accordingly. The relationship between the D-FBG wavelength shift and dissolved hydrogen concentration in oil was measured experimentally in the laboratory. The detected sensitivity could be as high as 1.96 μL/L at every 1-pm wavelength shift. The results proved that a simple, polished FBG-based hydrogen sensor provides a linear measuring characteristic in the range of low hydrogen concentrations in transformer oil. Moreover, the stable hydrogen sensing performance was investigated by X-ray diffraction analysis.

  8. Research on High Sensitive D-Shaped FBG Hydrogen Sensors in Power Transformer Oil

    Directory of Open Access Journals (Sweden)

    Ying-Ting Luo

    2016-10-01

    Full Text Available Dissolved hydrogen is a symbol gas decomposed by power transformer oil for electrical faults such as overheat or partial discharges. A novel D-shaped fiber Bragg grating (D-FBG sensor is herein proposed and was fabricated with magnetron sputtering to measure the dissolved hydrogen concentration in power transformer oil in this paper. Different from the RI (refractive index-based effect, D-FBG in this case is sensitive to curvature caused by stress from sensing coating, leading to Bragg wavelength shifts accordingly. The relationship between the D-FBG wavelength shift and dissolved hydrogen concentration in oil was measured experimentally in the laboratory. The detected sensitivity could be as high as 1.96 μL/L at every 1-pm wavelength shift. The results proved that a simple, polished FBG-based hydrogen sensor provides a linear measuring characteristic in the range of low hydrogen concentrations in transformer oil. Moreover, the stable hydrogen sensing performance was investigated by X-ray diffraction analysis.

  9. Statistical 3D shape analysis of gender differences in lateral ventricles

    Science.gov (United States)

    He, Qing; Karpman, Dmitriy; Duan, Ye

    2010-03-01

    This paper aims at analyzing gender differences in the 3D shapes of lateral ventricles, which will provide reference for the analysis of brain abnormalities related to neurological disorders. Previous studies mostly focused on volume analysis, and the main challenge in shape analysis is the required step of establishing shape correspondence among individual shapes. We developed a simple and efficient method based on anatomical landmarks. 14 females and 10 males with matching ages participated in this study. 3D ventricle models were segmented from MR images by a semiautomatic method. Six anatomically meaningful landmarks were identified by detecting the maximum curvature point in a small neighborhood of a manually clicked point on the 3D model. Thin-plate spline was used to transform a randomly selected template shape to each of the rest shape instances, and the point correspondence was established according to Euclidean distance and surface normal. All shapes were spatially aligned by Generalized Procrustes Analysis. Hotelling T2 twosample metric was used to compare the ventricle shapes between males and females, and False Discovery Rate estimation was used to correct for the multiple comparison. The results revealed significant differences in the anterior horn of the right ventricle.

  10. About brachytherapy for the handling of cancer

    International Nuclear Information System (INIS)

    Campos, Tarcisio P.R.; Silva, Nilton O.; Damaso, Renato S.; Costa, Helder R.; Borges, Paulo H.R.; Mendes, Bruno M.

    2000-01-01

    The technique of brachytherapy is argued in this article. The 'hardware' and 'necessary software' for the handling are summarily presented. Being the macro-dosimetry an important stage in the radiation therapy procedure, a simplified method of doses evaluation in conventional brachytherapy is presented. In an illustrative form, isodoses of a three-dimensional distribution of linear sources are drawn on a digitalized X-ray picture, exemplifying the handling of breast brachytherapy by sources of iridium

  11. Design and characterization of a 32P-patch for the treatment of skin diseases. Studies of its application as a betatherapeutic agent for modulated brachytherapy

    International Nuclear Information System (INIS)

    Salgueiro, M. J.

    2010-01-01

    The purpose of this work was to design and evaluate a 32 P-patch for contact brachytherapy of skin diseases. [ 32 P]-chromic phosphate in combination with silicone was employed to produce the designed 32 P patch. Radiopharmaceutical production was carried out in accordance with radiological safety issues. To verify the safety of the 32 P-patch, stability studies in vitro and in vivo were carried out to evaluate the leakage of radioactivity and autoradiographic studies were performed to evaluate the dose homogeneity and shielding. Therapeutic efficacy in animal models of skin cancer as well as in cats with squamous cell carcinoma was evaluated. These results showed that independently of the considered model, tumor growth was arrested and complete regressions were achieved in some other cases. Radiation doses were estimated with equations derived from the MIRD DOSE scheme and compared with Monte Carlo β doses. Some advantages of the designed 32 P-patch allow its use for conformal and modulated radiotherapy such as the possibility of modifying the activity concentration of the patch, the limited range of β- radiation, dose deep distribution and combination with bolus. This 32 P-patch which is easy to prepare and control may be used in the treatment of skin diseases alone or in combination with other treatment modalities. (author)

  12. Effect of brachytherapy technique and patient characteristics on cervical cancer implant dosimetry

    Energy Technology Data Exchange (ETDEWEB)

    Anker, Christopher J., E-mail: chris.anker@hci.utah.edu [Department of Radiation Oncology, Huntsman Cancer Hospital, University of Utah, Salt Lake City, UT (United States); O' Donnell, Kristen [Department of Radiation Oncology, The University of Arizona, Tucson, AZ (United States); Boucher, Kenneth M. [Department of Oncological Sciences, Huntsman Cancer Institute, University of Utah, Salt Lake City, UT (United States); Gaffney, David K. [Department of Radiation Oncology, Huntsman Cancer Hospital, University of Utah, Salt Lake City, UT (United States)

    2013-01-01

    Our purpose was to evaluate the relationship between brachytherapy technique and patient characteristics on dose to organs-at-risk (OARs) in patients undergoing high dose rate (HDR) brachytherapy for cervical cancer. From 1998 to 2008, 31 patients with cervical cancer with full dosimetric data were identified who received definitive external-beam radiation and HDR brachytherapy with tandem and ovoid applicators. Doses were recorded at point A, the International Commission on Radiation Units and Measurements (ICRU)-38 rectal point, the ICRU-38 bladder point, the vaginal surface, and the pelvic sidewall. Generalized estimating equations were used to determine the significance of changes in OAR to point A dose ratios with differences in brachytherapy technique or patient characteristics. Patients underwent a median of 5 brachytherapy procedures (range, 3 to 5), with a total of 179 procedures for 31 patients. For all brachytherapy treatments, the average ratios between the doses for the rectal, bladder, vaginal surface, and pelvic sidewall reference points to those at point A were 0.49, 0.59, 1.15, and 0.17, respectively. In general, decreased OAR dose was associated with a lower stage, younger age, increased ovoid size, increased tandem length, and earlier implant number. Increased tandem curvature significantly increased bladder dose and decreased rectal dose. Intravenous anesthesia usage was not correlated with improved dosimetry. This study allowed identification of patient and procedure characteristics influencing OAR dosing. Although the advent of 3-dimensional (3D) image-guided brachytherapy will bring new advances in treatment optimization, the actual technique involved at the time of the brachytherapy implant procedure will remain important.

  13. A study on applying Ra needle interstitial brachytherapy for oral cancer

    International Nuclear Information System (INIS)

    Yoshida, Shunichi; Komiya, Yoshiaki; Uchida, Ikuhiro; Tashiro, Kazuyoshi

    1999-01-01

    To investigate applicability of Ra needle interstitial brachytherapy, 93 cases of oral squamous carcinoma were examined. The patients underwent Ra needle interstitial brachytherapy as thorough therapy in our hospital. The criteria of applying Ra needle interstitial brachytherapy was diameter of within 5 cm and depth within 2 cm of tumor size. Ra needle interstitial brachytherapy was applied to 82 cases of tongue, 10 cases of oral floor and one case of lower lip carcinomas. The local control rate was 92.5%, and secondary neck metastasis was 32.3% in all cases applied Ra needle interstitial brachytherapy. The results were not bad compared with surgical treatment. However, the 5-year cumulative survival rate was 64.9%, which was not good enough at the result to obtain a good local control rate and secondary neck metastasis rate. The result was relative to low treatment result of local recurrence cases with Ra needle interstitial brachytherapy. To improve the result, it is important to distinguish local recurrence from radioinduced ulcer, and to start early secondary treatment. The cases in which cervical lymph node metastasis was found as the first examination underwent neck dessection after Ra needle interstitial brachytherapy. The 5-year cumulative survival rate was 83.3% in N1 cases and 40.6% in N2 cases, and the result of N2 cases was poorer than N1 cases with a significant difference. The results indicate that a needle having a diameter of within 5 cm, depth of within 2 cm and less than N1 can be applied during Ra needle interstitial brachytherapy for complete cure of cancer. (author)

  14. High-precision real-time 3D shape measurement based on a quad-camera system

    Science.gov (United States)

    Tao, Tianyang; Chen, Qian; Feng, Shijie; Hu, Yan; Zhang, Minliang; Zuo, Chao

    2018-01-01

    Phase-shifting profilometry (PSP) based 3D shape measurement is well established in various applications due to its high accuracy, simple implementation, and robustness to environmental illumination and surface texture. In PSP, higher depth resolution generally requires higher fringe density of projected patterns which, in turn, lead to severe phase ambiguities that must be solved with additional information from phase coding and/or geometric constraints. However, in order to guarantee the reliability of phase unwrapping, available techniques are usually accompanied by increased number of patterns, reduced amplitude of fringe, and complicated post-processing algorithms. In this work, we demonstrate that by using a quad-camera multi-view fringe projection system and carefully arranging the relative spatial positions between the cameras and the projector, it becomes possible to completely eliminate the phase ambiguities in conventional three-step PSP patterns with high-fringe-density without projecting any additional patterns or embedding any auxiliary signals. Benefiting from the position-optimized quad-camera system, stereo phase unwrapping can be efficiently and reliably performed by flexible phase consistency checks. Besides, redundant information of multiple phase consistency checks is fully used through a weighted phase difference scheme to further enhance the reliability of phase unwrapping. This paper explains the 3D measurement principle and the basic design of quad-camera system, and finally demonstrates that in a large measurement volume of 200 mm × 200 mm × 400 mm, the resultant dynamic 3D sensing system can realize real-time 3D reconstruction at 60 frames per second with a depth precision of 50 μm.

  15. An overview of interstitial brachytherapy and hyperthermia

    International Nuclear Information System (INIS)

    Brandt, B.B.; Harney, J.

    1989-01-01

    Interstitial thermoradiotherapy, an experimental cancer treatment that combines interstitial radiation implants (brachytherapy) and interstitial hyperthermia, is in the early stages of investigation. In accordance with the procedure used in a current national trial protocol, a 60-minute hyperthermia treatment is administered after catheters are placed into the tumor area while the patient is under general anesthesia. This is immediately followed by loading of radioactive Iridium-192 seeds into the catheters for a defined period of time. Once the prescribed radiation dose is delivered, the radioactive sources are removed and a second, 60-minute hyperthermia treatment is administered. Clinical trials with hyperthermia in combination with radiation have increased in recent years. Nurses caring for these patients need to become more knowledgeable about this investigational therapy. This paper provides an overview of the biologic rationale for this therapy, as well as a description of the delivery method and clinical application. Specific related nursing interventions are defined in a nursing protocol.23 references

  16. SU-D-19A-05: The Dosimetric Impact of Using Xoft Axxent® Electronic Brachytherapy Source TG-43 Dosimetry Parameters for Treatment with the Xoft 30 Mm Diameter Vaginal Applicator

    Energy Technology Data Exchange (ETDEWEB)

    Simiele, S; Micka, J; Culberson, W; DeWerd, L [University of WI-Madison/ADCL, Madison, WI (United States)

    2014-06-01

    Purpose: A full TG-43 dosimetric characterization has not been performed for the Xoft Axxent ® electronic brachytherapy source (Xoft, a subsidiary of iCAD, San Jose, CA) within the Xoft 30 mm diameter vaginal applicator. Currently, dose calculations are performed using the bare-source TG-43 parameters and do not account for the presence of the applicator. This work focuses on determining the difference between the bare-source and sourcein- applicator TG-43 parameters. Both the radial dose function (RDF) and polar anisotropy function (PAF) were computationally determined for the source-in-applicator and bare-source models to determine the impact of using the bare-source dosimetry data. Methods: MCNP5 was used to model the source and the Xoft 30 mm diameter vaginal applicator. All simulations were performed using 0.84p and 0.03e cross section libraries. All models were developed based on specifications provided by Xoft. The applicator is made of a proprietary polymer material and simulations were performed using the most conservative chemical composition. An F6 collision-kerma tally was used to determine the RDF and PAF values in water at various dwell positions. The RDF values were normalized to 2.0 cm from the source to accommodate the applicator radius. Source-in-applicator results were compared with bare-source results from this work as well as published baresource results. Results: For a 0 mm source pullback distance, the updated bare-source model and source-in-applicator RDF values differ by 2% at 3 cm and 4% at 5 cm. The largest PAF disagreements were observed at the distal end of the source and applicator with up to 17% disagreement at 2 cm and 8% at 8 cm. The bare-source model had RDF values within 2.6% of the published TG-43 data and PAF results within 7.2% at 2 cm. Conclusion: Results indicate that notable differences exist between the bare-source and source-in-applicator TG-43 simulated parameters. Xoft Inc. provided partial funding for this work.

  17. Effects of rear cavities on the wake behind an accelerating D-shaped bluff body

    Science.gov (United States)

    Lorite-Díez, M.; Jiménez-González, J. I.; Gutiérrez-Montes, C.; Martínez-Bazán, C.

    2018-04-01

    We investigate experimentally and numerically the transient development of the wake induced by a constant acceleration of a D-shaped bluff body, starting from rest and reaching a permanent regime of Reynolds number Re = 2000, under different values of acceleration and implementing three distinct rear geometrical configurations. Thus, alongside the classical blunt base, two control passive devices, namely, a straight cavity and an optimized, curved cavity, recently designed using adjoint optimization techniques, have also been used to assess their performance in transient flow conditions. Particle image velocimetry measurements were performed in a towing tank to characterize the near wake development in the early transient stages. It has been observed that the flow first develops symmetric shear layers with primary eddies attracted toward the base of the body due to the flow suction generated by the accelerated motion. Eventually, the interaction between the upper and lower shear layers provokes the destabilization of the flow and the symmetry breaking of the wake, finally giving rise to an alternate transitional vortex shedding regime. The transition between these phases is sped-up when the optimized cavity is used, reaching earlier the permanent flow conditions. In particular, the use of the optimized geometry has been shown to limit the growth of the primary eddies, decreasing both the recirculation and vortex formation length and providing with a more regularized, more organized vortex shedding. In addition, numerical simulations have been performed to evaluate the distribution of forces induced by the addition of rear cavities. In general, the aforementioned smoother and faster transition related to the use of optimized cavity translates into a lower averaged value of the drag coefficient, together with less energetic force fluctuations, regardless of the acceleration value.

  18. Object Recognition in Flight: How Do Bees Distinguish between 3D Shapes?

    Science.gov (United States)

    Werner, Annette; Stürzl, Wolfgang; Zanker, Johannes

    2016-01-01

    Honeybees (Apis mellifera) discriminate multiple object features such as colour, pattern and 2D shape, but it remains unknown whether and how bees recover three-dimensional shape. Here we show that bees can recognize objects by their three-dimensional form, whereby they employ an active strategy to uncover the depth profiles. We trained individual, free flying honeybees to collect sugar water from small three-dimensional objects made of styrofoam (sphere, cylinder, cuboids) or folded paper (convex, concave, planar) and found that bees can easily discriminate between these stimuli. We also tested possible strategies employed by the bees to uncover the depth profiles. For the card stimuli, we excluded overall shape and pictorial features (shading, texture gradients) as cues for discrimination. Lacking sufficient stereo vision, bees are known to use speed gradients in optic flow to detect edges; could the bees apply this strategy also to recover the fine details of a surface depth profile? Analysing the bees' flight tracks in front of the stimuli revealed specific combinations of flight maneuvers (lateral translations in combination with yaw rotations), which are particularly suitable to extract depth cues from motion parallax. We modelled the generated optic flow and found characteristic patterns of angular displacement corresponding to the depth profiles of our stimuli: optic flow patterns from pure translations successfully recovered depth relations from the magnitude of angular displacements, additional rotation provided robust depth information based on the direction of the displacements; thus, the bees flight maneuvers may reflect an optimized visuo-motor strategy to extract depth structure from motion signals. The robustness and simplicity of this strategy offers an efficient solution for 3D-object-recognition without stereo vision, and could be employed by other flying insects, or mobile robots.

  19. Validation of single-plane fluoroscopy and 2D/3D shape-matching for quantifying shoulder complex kinematics.

    Science.gov (United States)

    Lawrence, Rebekah L; Ellingson, Arin M; Ludewig, Paula M

    2018-02-01

    Fluoroscopy and 2D/3D shape-matching has emerged as the standard for non-invasively quantifying kinematics. However, its accuracy has not been well established for the shoulder complex when using single-plane fluoroscopy. The purpose of this study was to determine the accuracy of single-plane fluoroscopy and 2D/3D shape-matching for quantifying full shoulder complex kinematics. Tantalum markers were implanted into the clavicle, humerus, and scapula of four cadaveric shoulders. Biplane radiographs were obtained with the shoulder in five humerothoracic elevation positions (arm at the side, 30°, 60°, 90°, maximum). Images from both systems were used to perform marker tracking, while only those images acquired with the primary fluoroscopy system were used to perform 2D/3D shape-matching. Kinematics errors due to shape-matching were calculated as the difference between marker tracking and 2D/3D shape-matching and expressed as root mean square (RMS) error, bias, and precision. Overall RMS errors for the glenohumeral joint ranged from 0.7 to 3.3° and 1.2 to 4.2 mm, while errors for the acromioclavicular joint ranged from 1.7 to 3.4°. Errors associated with shape-matching individual bones ranged from 1.2 to 3.2° for the humerus, 0.5 to 1.6° for the scapula, and 0.4 to 3.7° for the clavicle. The results of the study demonstrate that single-plane fluoroscopy and 2D/3D shape-matching can accurately quantify full shoulder complex kinematics in static positions. Copyright © 2017 IPEM. Published by Elsevier Ltd. All rights reserved.

  20. Physical aspects of radioisotope brachytherapy

    International Nuclear Information System (INIS)

    1967-01-01

    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

  1. Rectourethral fistula following LDR brachytherapy.

    Science.gov (United States)

    Borchers, Holger; Pinkawa, Michael; Donner, Andreas; Wolter, Timm P; Pallua, Norbert; Eble, Michael J; Jakse, Gerhard

    2009-01-01

    Modern LDR brachytherapy has drastically reduced rectal toxicity and decreased the occurrence of rectourethral fistulas to <0.5% of patients. Therefore, symptoms of late-onset sequelae are often ignored initially. These fistulas cause severe patient morbidity and require interdisciplinary treatment. We report on the occurrence and management of a rectourethral fistula which occurred 4 years after (125)I seed implantation. Copyright 2009 S. Karger AG, Basel.

  2. Radiation safety and gynaecological brachytherapy

    International Nuclear Information System (INIS)

    Crawford, L.

    1985-01-01

    In 1983, the Radiation Control Section of the South Australian Health Commission conducted an investigation into radiation safety practices in gynaecological brachytherapy. Part of the investigation included a study of the transportation of radioactive sources between hospitals. Several deficiences in radiation safety were found in the way these sources were being transported. New transport regulations came into force in South Australia in July 1984 and since then there have been many changes in the transportation procedure

  3. Intravascular brachytherapy for peripheral vascular disease

    Directory of Open Access Journals (Sweden)

    Hagen, Anja

    2008-09-01

    Full Text Available Scientific background: Percutaneous transluminal angioplasties (PTA through balloon dilatation with or without stenting, i.e. vessel expansion through balloons with or without of implantation of small tubes, called stents, are used in the treatment of peripheral artery occlusive disease (PAOD. The intravascular vessel irradiation, called intravascular brachytherapy, promises a reduction in the rate of repeated stenosis (rate of restenosis after PTA. Research questions: The evaluation addresses questions on medical efficacy, cost-effectiveness as well as ethic, social and legal implications in the use of brachytherapy in PAOD patients. Methods: A systematic literature search was conducted in August 2007 in the most important medical electronic databases for publications beginning from 2002. The medical evaluation included randomized controlled trials (RCT. The information synthesis was performed using meta-analysis. Health economic modeling was performed with clinical assumptions derived from the meta-analysis and economical assumptions derived from the German Diagnosis Related Groups (G-DRG-2007. Results: Medical evaluation: Twelve publications about seven RCT on brachytherapy vs. no brachytherapy were included in the medical evaluation. Two RCT showed a significant reduction in the rate of restenosis at six and/or twelve months for brachytherapy vs. no brachytherapy after successful balloon dilatation, the relative risk in the meta-analysis was 0.62 (95% CI: 0.46 to 0.84. At five years, time to recurrence of restenosis was significantly delayed after brachytherapy. One RCT showed a significant reduction in the rate of restenosis at six months for brachytherapy vs. no brachytherapy after PTA with optional stenting, the relative risk in the meta-analysis was 0.76 (95% CI: 0.61 to 0.95. One RCT observed a significantly higher rate of late thrombotic occlusions after brachytherapy in the subgroup of stented patients. A single RCT for brachytherapy

  4. Interstitial prostate brachytherapy. LDR-PDR-HDR

    International Nuclear Information System (INIS)

    Kovacs, Gyoergy; Hoskin, Peter

    2013-01-01

    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.

  5. HDR brachytherapy for superficial non-melanoma skin cancers

    International Nuclear Information System (INIS)

    Gauden, Ruth; Pracy, Martin; Avery, Anne-Marie; Hodgetts, Ian; Gauden, Stan

    2013-01-01

    Our initial experience using recommended high dose per fraction skin brachytherapy (BT) treatment schedules, resulted in poor cosmesis. This study aimed to assess in a prospective group of patients the use of Leipzig surface applicators for High Dose Rate (HDR) brachytherapy, for the treatment of small non-melanoma skin cancers (NMSC) using a protracted treatment schedule. Treatment was delivered by HDR brachytherapy with Leipzig applicators. 36Gy, prescribed to between 3 to 4mm, was given in daily 3Gy fractions. Acute skin toxicity was evaluated weekly during irradiation using the Radiation Therapy Oncology Group criteria. Local response, late skin effects and cosmetic results were monitored at periodic intervals after treatment completion. From March 2002, 200 patients with 236 lesions were treated. Median follow-up was 66 months (range 25–121 months). A total of 162 lesions were macroscopic, while in 74 cases, BT was given after resection because of positive microscopic margins. There were 121 lesions that were basal cell carcinomas, and 115 were squamous cell carcinomas. Lesions were located on the head and neck (198), the extremities (26) and trunk (12). Local control was 232/236 (98%). Four patients required further surgery to treat recurrence. Grade 1 acute skin toxicity was detected in 168 treated lesions (71%) and grade 2 in 81 (34%). Cosmesis was good or excellent in 208 cases (88%). Late skin hypopigmentation changes were observed in 13 cases (5.5%). Delivering 36Gy over 2 weeks to superficial NMSC using HDR brachytherapy is well tolerated and provides a high local control rate without significant toxicity.

  6. Substantial advantage of CT-planned HDR brachytherapy for cervical cancer patients compared to a historical series with regard to local control and toxicity?; Substantieller Vorteil durch CT-geplante HDR-Brachytherapie bei Zervixkarzinompatientinnen im Vergleich zu historischen Serien bezueglich lokaler Kontrolle und Toxizitaet

    Energy Technology Data Exchange (ETDEWEB)

    Marnitz, Simone [Klinik fuer Strahlentherapie der Uniklinik Koeln, Medizinische Fakultaet der Universitaet zu Koeln, CyberKnife Centrum, Koeln (Germany)

    2017-03-15

    The primary radiochemotherapy is the standard treatment for patients with nodal positive and/or locally advanced cervical carcinoma. The therapy consists of percutaneous radiotherapy, simultaneous chemotherapy with cisplatin and an intracervical brachytherapy. The application of highly standardized brachytherapy based on NMR imaging allowed an improved local contol and a considerable reduction of toxicity.

  7. Comparison of different application systems and CT- assisted treatment planning procedures in primary endometrium cancer: Is it technically possible to include the whole uterus volume in the volume treated by brachytherapy

    International Nuclear Information System (INIS)

    Mock, U.; Knocke, Th.; Fellner, C.; Poetter, R.

    1996-01-01

    Purpose: Brachytherapy is regarded as the definitive component of treatment for inoperable patients with endometrium cancer. In published series the whole uterus has been claimed to represent the target volume independently of the individual tumor spread. The purpose of this work is to compare different planning and application procedures and to analyze the target volumes (whole uterus), treatment volumes and their respective relation for the given various conditions. Material and Methods: In ten patients with primary endometrium cancer the correlation between target- and treatment volume was analysed based on standard one-channel applicators or individual Heyman applicators. A comparative analysis of target volumes resulting from two different planning procedures of Heyman applications was performed. CT was carried out after insertion of the Heyman ovoids. Target volume was estimated by measuring the uterus size at different cross sections of the CT images. Dose calculation was performed with (PLATO-system) or without (NPS-system) transferring these data directly to the planning system. We report on the differences in treatment volumes resulting from the two application and planning systems. Results: The mean value of the uterus volume was 180 ccm (range 57 ccm to 316 ccm). Four out of 10 patients had an asymmetric uterus configuration with a side-difference (in longitudinal or transversal direction) of more than 1 cm. On average 70% (range 48-95%) of the uterus volume was included by the treatment volume when Heymann applicators were used compared to 45 % (range 25-89%) when standard one channel applicators were used. This represents an improvement of 25% (range from 11%-35%). By utilizing the more sophisticated way of treatment planning a more adequate coverage of the uterus volume was achieved in five out of ten patients. The treated volume increased on the average by 20 % (range 11 %-32%). In three cases changes in the irradiation volume were less than 5%. In

  8. HDR brachytherapy. An option for preventing nonmalignant obstruction in patients after lung transplantation

    Energy Technology Data Exchange (ETDEWEB)

    Meyer, A.; Karstens, J.H.; Christiansen, H. [Medical School Hannover (Germany). Dept. of Radiation Oncology; Warszawski-Baumann, A.; Baumann, R. [Medical School Hannover (Germany). Dept. of Radiation Oncology; Medical Practice for Radiotherapy and Radiation Oncology, Hannover (Germany); Gottlieb, J.; Welte, T. [Medical School Hannover (Germany). Dept. of Respiratory Medicine

    2012-12-15

    Purpose: Interventional bronchoscopy is the main treatment modality in managing benign airway obstructions following lung transplantation. We analyzed the effect of intraluminal brachytherapy on preventing recurrence of hyperplastic tissue. Patients and methods: From September 2002 to September 2004, a total of 24 intraluminal brachytherapy applications were carried out on 12 lung transplant patients in 15 different locations. A single dose of 3 Gy was calculated at a 5-mm distance from the catheter surface; the target volume included a stenosis plus safety interval of 0.5-1.0 cm. Results: All patients had a mean 10.6 local interventions (Argon plasma coagulation, balloon dilatations, stenting) over 4.4 months before the first application of endobronchial brachytherapy, with a mean amount of 2.4 applications per month. The mean forced expiratory volume in 1 s (FEV1) was 2,219 ml in the 3 months before application of brachytherapy. After endobronchial brachytherapy, all patients experienced improvement in clinical status and respiratory function. The mean level of FEV1 in the 3 months after application was 2,435 ml (p = 0.02), and the number of invasive interventions dropped to a mean rate of 5.2 interventions in the 5.1 months after the first intervention, with an amount of 1 application per month. No treatment-related complications were seen. Four patients were treated twice, 1 patient three times, and 1 patient four times at the same localization. Conclusions: Recurrent symptomatic benign airway obstruction from hyperplastic tissue in the bronchus after lung transplantation can be successfully treated with intraluminal high-dose-rate brachytherapy with a dose of 3 Gy at a 5-mm distance from the catheter surface and a longitudinal safety margin of 1 cm. (orig.)

  9. HDR brachytherapy. An option for preventing nonmalignant obstruction in patients after lung transplantation

    International Nuclear Information System (INIS)

    Meyer, A.; Karstens, J.H.; Christiansen, H.; Gottlieb, J.; Welte, T.

    2012-01-01

    Purpose: Interventional bronchoscopy is the main treatment modality in managing benign airway obstructions following lung transplantation. We analyzed the effect of intraluminal brachytherapy on preventing recurrence of hyperplastic tissue. Patients and methods: From September 2002 to September 2004, a total of 24 intraluminal brachytherapy applications were carried out on 12 lung transplant patients in 15 different locations. A single dose of 3 Gy was calculated at a 5-mm distance from the catheter surface; the target volume included a stenosis plus safety interval of 0.5-1.0 cm. Results: All patients had a mean 10.6 local interventions (Argon plasma coagulation, balloon dilatations, stenting) over 4.4 months before the first application of endobronchial brachytherapy, with a mean amount of 2.4 applications per month. The mean forced expiratory volume in 1 s (FEV1) was 2,219 ml in the 3 months before application of brachytherapy. After endobronchial brachytherapy, all patients experienced improvement in clinical status and respiratory function. The mean level of FEV1 in the 3 months after application was 2,435 ml (p = 0.02), and the number of invasive interventions dropped to a mean rate of 5.2 interventions in the 5.1 months after the first intervention, with an amount of 1 application per month. No treatment-related complications were seen. Four patients were treated twice, 1 patient three times, and 1 patient four times at the same localization. Conclusions: Recurrent symptomatic benign airway obstruction from hyperplastic tissue in the bronchus after lung transplantation can be successfully treated with intraluminal high-dose-rate brachytherapy with a dose of 3 Gy at a 5-mm distance from the catheter surface and a longitudinal safety margin of 1 cm. (orig.)

  10. Local vaginal anesthesia during high-dose-rate intracavitary brachytherapy for cervical cancer

    International Nuclear Information System (INIS)

    Chen, H.-C.; Wan Leung, Stephen; Wang, C.-J.; Sun, L.-M.; Fang, F.-M.; Huang, E.-Y.; Wang, S.-J.; Yang, C.-W.

    1998-01-01

    Purpose: To evaluate the clinical efficacy of local vaginal lidocaine application for pain relief during high-dose-rate (HDR) intracavitary brachytherapy for patients with cervical cancer, and to investigate sequential changes in serum levels of lidocaine during the procedures. Methods and Materials: This prospective study was designed to examine the analgesic effect, physical response, and side effects of local anesthesia during HDR intracavitary brachytherapy. Forty patients were enrolled. All patients received 10-15 MV X-rays to the pelvis with a total dose of 45-59.4 Gy 5-6 weeks before undergoing HDR intracavitary brachytherapy. All patients underwent first intracavitary brachytherapy under general anesthesia. These patients were randomly allocated to receive one of two different treatment protocols as follows: (1) treatment session - control session - treatment session - control session; or (2) control session - treatment session- control session - treatment session. In the treatment sessions, topical anesthesia was administered using 4 ml of 10% lidocaine solution sprayed liberally on the cervix and vagina during intracavitary brachytherapy. In the control sessions, a placebo was administered in the same manner during brachytherapy. The Hensche's applicators for brachytherapy were inserted into the cervix and vagina 5 min after lidocaine application. The visual analogue scale (VAS) was used to assess pain and discomfort during brachytherapy. Blood pressure and heart rates were measured to evaluate the physiological response. Another prospective study was then performed to investigate the sequential changes of serum lidocaine levels during the anesthetic procedure. Eleven additional patients with similar disease state and demographic characteristics were enrolled and blood samples were obtained before, and 5, 15, 30, and 45 min after the initiation of lidocaine application. Results: The mean VAS values recorded during the treatment sessions and control

  11. High dose rate brachytherapy for oral cancer

    International Nuclear Information System (INIS)

    Yamazaki, Hideya; Yoshida, Ken; Yoshioka, Yasuo; Shimizutani, Kimishige; Koizumi, Masahiko; Ogawa, Kazuhiko; Furukawa, Souhei

    2013-01-01

    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)

  12. High dose rate brachytherapy for oral cancer.

    Science.gov (United States)

    Yamazaki, Hideya; Yoshida, Ken; Yoshioka, Yasuo; Shimizutani, Kimishige; Furukawa, Souhei; Koizumi, Masahiko; Ogawa, Kazuhiko

    2013-01-01

    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.

  13. Implementing MRI-based target delineation for cervical cancer treatment within a rapid workflow environment for image-guided brachytherapy: A practical approach for centers without in-room MRI.

    Science.gov (United States)

    Trifiletti, Daniel M; Libby, Bruce; Feuerlein, Sebastian; Kim, Taeho; Garda, Allison; Watkins, W Tyler; Erickson, Sarah; Ornan, Afshan; Showalter, Timothy N

    2015-01-01

    Magnetic resonance imaging (MRI)-based intracavitary brachytherapy offers several advantages over computed tomography (CT)-based brachytherapy, but many centers are unable to offer it at the time of brachytherapy because of logistic and/or financial considerations. We have implemented a method of integrating MRI into a CT-guided, high-dose-rate intracavitary brachytherapy workflow in clinics that do not have immediately available MRI capability. At our institution, patients receiving high-dose-rate intracavitary brachytherapy as a component of the definitive treatment of cervical cancer have a Smit sleeve placed during the first brachytherapy fraction in a dedicated suite with in-room CT-on-rails. After the first fraction of brachytherapy, an MRI is obtained with the Smit sleeve, but no applicator, in place. For each subsequent fraction, CT scans are coregistered to the MRI scan by the Smit sleeve. The gross target volume is defined by MRI and overlaid on the CT images for each brachytherapy treatment for dose optimization. This MRI-integrated workflow adds workflow is a feasible compromise to preserve an efficient workflow while integrating MRI target delineation, and it provides many of the advantages of both MRI- and CT-based brachytherapy. The future collection and analysis of clinical data will serve to compare the proposed approach to non-MRI containing techniques. Copyright © 2015 American Brachytherapy Society. Published by Elsevier Inc. All rights reserved.

  14. 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

  15. 3D base: a geometrical data base system for the analysis and visualisation of 3D-shapes obtained from parallel serial sections including three different geometrical representations

    NARCIS (Netherlands)

    Verbeek, F. J.; de Groot, M. M.; Huijsmans, D. P.; Lamers, W. H.; Young, I. T.

    1993-01-01

    In this paper we discuss a geometrical data base that includes three different geometrical representations of one and the same reconstructed 3D shape: the contour-pile, the voxel enumeration, and the triangulation of a surface. The data base is tailored for 3D shapes obtained from plan-parallel

  16. American Brachytherapy Society recommendations for reporting morbidity after prostate brachytherapy

    International Nuclear Information System (INIS)

    Nag, Subir; Ellis, Rodney J.; Merrick, Gregory S.; Bahnson, Robert; Wallner, Kent; Stock, Richard

    2002-01-01

    Purpose: To standardize the reporting of brachytherapy-related prostate morbidity to guide ongoing clinical practice and future investigations. Methods: Members of the American Brachytherapy Society (ABS) with expertise in prostate brachytherapy performed a literature review and, guided by their clinical experience, formulated specific recommendations for reporting on morbidity related to prostate brachytherapy. Results: The ABS recommends using validated, patient-administered health-related quality-of-life instruments for the determination of baseline and follow-up data regarding bowel, urinary, and sexual function. Both actuarial and crude incidences should be reported, along with the temporal resolution of specific complications, and correlated with the doses to the normal tissues. The International Prostate Symptom Score is recommended to assess urinary morbidity, and any dysuria, gross hematuria, urinary retention, incontinence, or medication use should be quantified. Likewise, the ''Sexual Health Inventory for Men,'' which includes the specific erectile questions of the International Index of Erectile Function, is the preferred instrument for reporting sexual function, and the loss of sexual desire, incidence of hematospermia, painful orgasm (orgasmalgia), altered orgasm intensity, decreased ejaculatory volume, use of erectile aids, and use of hormones for androgen deprivation should be quantified. The ABS recommends adoption of the Radiation Therapy Oncology Group/European Organization for Research and Treatment of Cancer acute and late radiation morbidity scoring scheme for reporting rectal morbidity and noting the incidence of rectal steroid, laser, or antidiarrheal use. Conclusion: It is important to focus on health-related quality-of-life issues in the treatment of prostate cancer, because the control rates are very similar between appropriate treatment modalities. The ABS recommends using the International Prostate Symptom Score, International Index of

  17. Invited review, recent developments in brachytherapy source dosimetry

    International Nuclear Information System (INIS)

    Meigooni, A.S.

    2004-01-01

    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

  18. Patterns of care for brachytherapy in Europe: Updated results

    International Nuclear Information System (INIS)

    Guedea, Ferran; Venselaar, Jack; Hoskin, Peter; Hellebust, Taran Paulsen; Peiffert, Didier; Londres, Bradley; Ventura, Montse; Mazeron, Jean-Jacques; Van Limbergen, Erik; Poetter, Richard; Kovacs, Gyorgy

    2010-01-01

    Objective: This descriptive survey evaluated brachytherapy (BT) practices and resources in the European area. This was a follow-up study to the original patterns of care for brachytherapy in Europe (PCBE). Materials and methods: A total of 1121 radiotherapy (RT) centres from 41 countries were asked to complete an online questionnaire on BT practices and resources. Countries with fewer than 50% of centres responding were excluded. Participating countries were divided into three groups based on gross domestic product (GDP); group I contained the countries with the highest GDP. Results: The response rate was 56% (633/1121 centres) with 30/41 countries (73%) meeting the inclusion criteria. Sixty percent of reporting centres provided brachytherapy. Responding centres treated an average of 138 (±10, 1 SD) patients with BT; in group I, the mean was 110/centre, an increase of 18% from 2002. CT-dosimetry increased to 61% of centres vs. 33% in 2002. HDR (high-dose rate) BT was the most commonly reported technique (65% of centres). Most BT interventions were for gynaecological tumors (59% of all cases), followed by prostate (17%), breast (9%), lung/bronchus (3%), and esophagus tumors(2%). Conclusion: Gynaecological BT remains the most common application, although both prostate and breast BT have increased. CT-based dosimetry has become increasingly common since 2002. The use of HDR and PDR (pulsed-dose rate) techniques has increased markedly, while both LDR and MDR (medium-dose rate) have declined.

  19. Development of a Remote Handling Robot for the Maintenance of an ITER-Like D-Shaped Vessel

    Directory of Open Access Journals (Sweden)

    Peihua Chen

    2014-01-01

    Full Text Available Robotic operation is one of the major challenges in the remote maintenance of ITER vacuum vessel (VV and future fusion reactors as inner operations of Tokamak have to be done by robots due to the internal adverse conditions. This paper introduces a novel remote handling robot (RHR for the maintenance of ITER-like D-shaped vessel. The modular designed RHR, which is an important part of the remote handling system for ITER, consists of three parts: an omnidirectional transfer vehicle (OTV, a planar articulated arm (PAA, and an articulated teleoperated manipulator (ATM. The task of RHR is to carry processing tools, such as the viewing system, leakage detector, and electric screwdriver, to inspect and maintain the components installed inside the D-shaped vessel. The kinematics of the OTV, as well as the kinematic analyses of the PAA and ATM, is studied in this paper. Because of its special length and heavy payload, the dynamics of the PAA is also investigated through a dynamic simulation system based on robot technology middleware (RTM. The results of the path planning, workspace simulations, and dynamic simulation indicate that the RHR has good mobility together with satisfying kinematic and dynamic performances and can well accomplish its maintenance tasks in the ITER-like D-shaped vessel.

  20. A spherical harmonics intensity model for 3D segmentation and 3D shape analysis of heterochromatin foci.

    Science.gov (United States)

    Eck, Simon; Wörz, Stefan; Müller-Ott, Katharina; Hahn, Matthias; Biesdorf, Andreas; Schotta, Gunnar; Rippe, Karsten; Rohr, Karl

    2016-08-01

    The genome is partitioned into regions of euchromatin and heterochromatin. The organization of heterochromatin is important for the regulation of cellular processes such as chromosome segregation and gene silencing, and their misregulation is linked to cancer and other diseases. We present a model-based approach for automatic 3D segmentation and 3D shape analysis of heterochromatin foci from 3D confocal light microscopy images. Our approach employs a novel 3D intensity model based on spherical harmonics, which analytically describes the shape and intensities of the foci. The model parameters are determined by fitting the model to the image intensities using least-squares minimization. To characterize the 3D shape of the foci, we exploit the computed spherical harmonics coefficients and determine a shape descriptor. We applied our approach to 3D synthetic image data as well as real 3D static and real 3D time-lapse microscopy images, and compared the performance with that of previous approaches. It turned out that our approach yields accurate 3D segmentation results and performs better than previous approaches. We also show that our approach can be used for quantifying 3D shape differences of heterochromatin foci. Copyright © 2016 Elsevier B.V. All rights reserved.

  1. Fully automated MRI-guided robotics for prostate brachytherapy

    International Nuclear Information System (INIS)

    Stoianovici, D.; Vigaru, B.; Petrisor, D.; Muntener, M.; Patriciu, A.; Song, D.

    2008-01-01

    The uncertainties encountered in the deployment of brachytherapy seeds are related to the commonly used ultrasound imager and the basic instrumentation used for the implant. An alternative solution is under development in which a fully automated robot is used to place the seeds according to the dosimetry plan under direct MRI-guidance. Incorporation of MRI-guidance creates potential for physiological and molecular image-guided therapies. Moreover, MRI-guided brachytherapy is also enabling for re-estimating dosimetry during the procedure, because with the MRI the seeds already implanted can be localised. An MRI compatible robot (MrBot) was developed. The robot is designed for transperineal percutaneous prostate interventions, and customised for fully automated MRI-guided brachytherapy. With different end-effectors, the robot applies to other image-guided interventions of the prostate. The robot is constructed of non-magnetic and dielectric materials and is electricity free using pneumatic actuation and optic sensing. A new motor (PneuStep) was purposely developed to set this robot in motion. The robot fits alongside the patient in closed-bore MRI scanners. It is able to stay fully operational during MR imaging without deteriorating the quality of the scan. In vitro, cadaver, and animal tests showed millimetre needle targeting accuracy, and very precise seed placement. The robot tested without any interference up to 7T. The robot is the first fully automated robot to function in MRI scanners. Its first application is MRI-guided seed brachytherapy. It is capable of automated, highly accurate needle placement. Extensive testing is in progress prior to clinical trials. Preliminary results show that the robot may become a useful image-guided intervention instrument. (author)

  2. The role of long half-life isotopes for use in LDR brachytherapy. Report of the advisory group meeting (325-E3-AG-1086)

    International Nuclear Information System (INIS)

    2000-08-01

    Brachytherapy is a growing activity in the management of cancer. Where indications exist for brachytherapy, LDR still retains a significant but decreasingly important role in the overall management. It remains the preferred form of brachytherapy in a few sites such as the nose, lip, vagina and penis. It is well tested in the paediatric population where long-term sequelae are highly significant and have not yet been evaluated for mHDR. Prostatic cancer permanent seed implant boosts is currently the only application where LDR is receiving increasing clinical support. LDR still can play an equally effective role when brachytherapy is required in gynaecological, breast and head and neck cancer and soft tissue sarcomas. The meeting recognised the growing role of mHDR as the major modality in brachytherapy administration. It is further noted that changing circumstances and opinions regarding mHDR may exert a major influence on the continued future of LDR as a treatment modality. LDR brachytherapy special techniques are becoming less widely distributed and less frequently performed. Only a few centres remain where sufficient procedures are performed to give adequate training in a period of a few months. The meeting recommended that the Agency should promote the creation of regional training centres of excellence where the practice of LDR brachytherapy should be available. The meeting recommended that the Member States should continue support for LDR brachytherapy techniques beyond gynaecological techniques until such time as clear evidence is presented for discontinuation

  3. TU-CD-207-09: Analysis of the 3-D Shape of Patients’ Breast for Breast Imaging and Surgery Planning

    Energy Technology Data Exchange (ETDEWEB)

    Agasthya, G; Sechopoulos, I [Emory University, Atlanta, GA (United States)

    2015-06-15

    Purpose: Develop a method to accurately capture the 3-D shape of patients’ external breast surface before and during breast compression for mammography/tomosynthesis. Methods: During this IRB-approved, HIPAA-compliant study, 50 women were recruited to undergo 3-D breast surface imaging during breast compression and imaging for the cranio-caudal (CC) view on a digital mammography/breast tomosynthesis system. Digital projectors and cameras mounted on tripods were used to acquire 3-D surface images of the breast, in three conditions: (a) positioned on the support paddle before compression, (b) during compression by the compression paddle and (c) the anterior-posterior view with the breast in its natural, unsupported position. The breast was compressed to standard full compression with the compression paddle and a tomosynthesis image was acquired simultaneously with the 3-D surface. The 3-D surface curvature and deformation with respect to the uncompressed surface was analyzed using contours. The 3-D surfaces were voxelized to capture breast shape in a format that can be manipulated for further analysis. Results: A protocol was developed to accurately capture the 3-D shape of patients’ breast before and during compression for mammography. Using a pair of 3-D scanners, the 50 patient breasts were scanned in three conditions, resulting in accurate representations of the breast surfaces. The surfaces were post processed, analyzed using contours and voxelized, with 1 mm{sup 3} voxels, converting the breast shape into a format that can be easily modified as required. Conclusion: Accurate characterization of the breast curvature and shape for the generation of 3-D models is possible. These models can be used for various applications such as improving breast dosimetry, accurate scatter estimation, conducting virtual clinical trials and validating compression algorithms. Ioannis Sechopoulos is consultant for Fuji Medical Systems USA.

  4. Physical aspects of endovascular brachytherapy

    International Nuclear Information System (INIS)

    Kirisits, C.

    2001-11-01

    Restenosis is severely limiting the outcome of vascular interventions. In several clinical trials endovascular brachytherapy has shown to reduce the restenosis rate. Local radiotherapy to the injured vessel wall is a promising new type of treatment in order to inhibit a complex wound healing process resulting in cell proliferation and re-obstruction of the treated vessel. Treatment planning has to be based on the dose distribution in the vicinity of the sources used. Source strength was determined in terms of air kerma rate for gamma nuclides (Iridium-192) and absorbed dose to water at reference distance of 2 mm for beta nuclides (Strontium-90/Yttrium-90, Phosphor-32), respectively. Radial dose profiles and the Reference Isodose Length (RIL) were determined using the EGSnrc code and GafChromic film. Good agreement was found between both methods. In order to treat the entire clinical target length, the (RIL) is an essential value during treatment planning. Examples are described for different levels of treatment planing including recommendations for optimal choice and positioning of the radioactive devices inside the artery. IVUS based treatment planning is illustrated with superposition of isodoses on cross-sectional images. A calculation model for radioactive stents is presented in order to determine dose volume histograms in a retrospective analysis. Radiation protection issues for endovascular brachytherapy are discussed in detail. Personal dose for the involved personnel is estimated based on calculations and measurements. Beta ray dosimetry is performed with suitable detectors. In order to estimate the exposure to the patient the dose to organs at risk is calculated and compared to the dose from angiography. There is an additional radiation exposure to patients and personnel caused by endovascular brachytherapy, but the values are much smaller than those caused by diagnostic angiography. (author)

  5. American Brachytherapy Society Task Group Report: Combination of brachytherapy and external beam radiation for high-risk prostate cancer.

    Science.gov (United States)

    Spratt, Daniel E; Soni, Payal D; McLaughlin, Patrick W; Merrick, Gregory S; Stock, Richard G; Blasko, John C; Zelefsky, Michael J

    To review outcomes for high-risk prostate cancer treated with combined modality radiation therapy (CMRT) utilizing external beam radiation therapy (EBRT) with a brachytherapy boost. The available literature for high-risk prostate cancer treated with combined modality radiation therapy was reviewed and summarized. At this time, the literature suggests that the majority of high-risk cancers are curable with multimodal treatment. Several large retrospective studies and three prospective randomized trials comparing CMRT to dose-escalated EBRT have demonstrated superior biochemical control with CMRT. Longer followup of the randomized trials will be required to determine if this will translate to a benefit in metastasis-free survival, disease-specific survival, and overall survival. Although greater toxicity has been associated with CMRT compared to EBRT, recent studies suggest that technological advances that allow better definition and sparing of critical adjacent structures as well as increasing experience with brachytherapy have improved implant quality and the toxicity profile of brachytherapy. The role of androgen deprivation therapy is well established in the external beam literature for high-risk disease, but there is controversy regarding the applicability of these data in the setting of dose escalation. At this time, there is not sufficient evidence for the omission of androgen deprivation therapy with dose escalation in this population. Comparisons with surgery remain limited by differences in patient selection, but the evidence would suggest better disease control with CMRT compared to surgery alone. Due to a series of technological advances, modern combination series have demonstrated unparalleled rates of disease control in the high-risk population. Given the evidence from recent randomized trials, combination therapy may become the standard of care for high-risk cancers. Copyright © 2016 American Brachytherapy Society. Published by Elsevier Inc. All

  6. SU-G-201-12: Investigation of Beta-Emitter 90Sr-90Y Dose Distribution Using Gafchromic EBT3 Film for Application On Conformal Skin Brachytherapy Device

    International Nuclear Information System (INIS)

    Ferreira, C; Johnson, D; Ahmad, S; Rasmussen, K; Jung, J

    2016-01-01

    Purpose: To investigate 90 Sr- 90 Y as a high dose rate (HDR) source for application in a conformal skin brachytherapy (CSBT) device. The CSBT device has been previously developed to provide patient specific treatment for small inoperable lesions and irregular surfaces. Methods: A popular beta emitter, 90 Sr- 90 Y was tested for feasibility in a CSBT device. A 1 cm diameter plaque was used to deliver dose to a solid water phantom containing EBT3 Gafchromic films arranged at the surface and perpendicular to it. Additionally, a 1 cm diameter 6 MeV electron beam was used to irradiate EBT3 film at 100 cm SSD with a 0.5 cm bolus. Films were digitized with an Epson Expression 10000 XL scanner and calibrated with a 6 MeV electron specific dose curve. Normalized percent depth doses (PDD) and dose profiles for both techniques were analyzed using ImageJ. Results: Dose distributions achieved with the 90 Sr- 90 Y sources were compared with those of external electron beam radiation therapy (EBRT). Penumbra (20%- 80%) for EBRT and 90Sr-90Y were 4.3 mm and 1.6 mm, respectively. PDD values of 50% (normalized to 2 mm) were 10.1 mm and 2.8 mm for electron and 90 Sr- 90 Y, respectively. Flatness (80% of the central beam profile) was 14.1% at a 5 mm depth for EBRT and 4.0% at surface for the 90 Sr- 90 Y. Conclusion: As expected, the PDDs of 90 Sr- 90 Y in water are shallower than that of external electron beams for the same field size. 90 Sr- 90 Y can be used in CSBT to provide patient specific treatment where shallower depth doses than that provided by electron external beams may be required: e.g. eyelids, nose, lips, ears, etc. The customizability of EBRT could be replicated by using multiple adjacent 90 Sr- 90 Y plaque placements.

  7. Guidelines for comprehensive quality assurance in brachytherapy

    International Nuclear Information System (INIS)

    Goldson, A.L.; Nibhanupudy, J.R.

    1984-01-01

    Brachytherapy treatment techniques can provide significant improvement in local control and overall survival, but only when quality assurance can be guaranteed. To establish brachytherapy quality assurance, basic requirements for three predetermined subdivisions of clinical institutions will be forwarded. These are: (1) centers having minimum requirements to provide brachytherapy, (2) intermediate centers such as regional or community hospitals, and (3) optimal centers such as university hospital and cancer centers. This presentation will highlight personnel needs, equipment requirements, academic activities, clinical experience with these systems and proposed quality assurance guidelines

  8. Radiographic Control of 137-Cs Brachytherapy Sources

    International Nuclear Information System (INIS)

    Bistrovic, M.; Viculin, T.; Jurkovic, S.

    2003-01-01

    1 37C s brachytherapy sources are practical for the intracavitary application due to their relatively long lifetime (T 1/2 = 30 y). On the other hand, due to the relatively low energy (0.66 MeV) of the emitted photons, they are suitable for an efficient radiation protection. The dose distribution around the sources is usually calculated by a specific program. However this program requires the knowledge of the position of sources within the applicator as well as the distribution of activity along them. The only way to learn these data is to make an X-ray picture of applicators and sources superimposed to the autoradiography of every source. It is difficult to achieve satisfactory radiographs with high dose rate sources with standard X-ray film material because autoradiography covers the structure of the radiographic shadow. The problem can be overcome either by applying a high intensity X-ray or gamma beam (originating from a radiotherapeutic machine), or by using photographic material of very low sensitivity, for example photographic paper. Combining both possibilities one can obtain satisfactory images. (author)

  9. The Meaning and Experience of Patients Undergoing Rectal High-Dose-Rate Brachytherapy.

    Science.gov (United States)

    Perez, Samara; Néron, Sylvain; Benc, Renata; Rosberger, Zeev; Vuong, Té

    2016-01-01

    High-dose-rate (HDR) brachytherapy is a precise form of radiation therapy that targets cancerous tumors by directly applying the radiation source at the site or directly next to the tumor. Patients often experience but underreport pain and anxiety related to cancer treatments. At present, there is no research available concerning the pervasiveness and intensity of patients' pain and anxiety during rectal brachytherapy. The aim of this study was to examine patients' thoughts, emotions, coping strategies, physical sensations, and needs during rectal HDR brachytherapy treatment. Twenty-five patients with rectal cancer were interviewed using a semi-structured qualitative interview following the completion of their brachytherapy treatment delivered at a Montreal-based hospital in Quebec, Canada. The experiences of pain and discomfort varied greatly between patients and were linked to the meaning patients attributed to the treatment itself, sense of time, the body's lithotomic position, insertion of the treatment applicator, and the patients' sense of agency and empowerment during the procedure. Patients drew upon a variety of internal and external resources to help them cope with discomfort. Staff need to know about the variation in the physical and emotional experiences of patients undergoing this treatment. Clinical teams can tailor their procedural behavior (eg, using certain language, psychosocial interventions) according to patients' needs to increase patients' comfort and ultimately improve their experience of HDR rectal brachytherapy.

  10. Development of the Dutch primary standard for beta-emitting brachytherapy sources

    International Nuclear Information System (INIS)

    Marel, J. an der; Dijk, E. van

    2002-01-01

    The application of β-radiation emitting radioactive sources in medicine is rapidly expanding. An important new application is the use of β-radiation emitting radioactive sources in endovascular brachytherapy to avoid restenosis. Another well-known application is the use of the ophthalmic applicator (flat or concave surface source) for the treatment of tumors in the eye. Dose and dose distributions are very important characteristics of brachytherapy sources. The absorbed dose in the treated tissue should be known accurately to assure a good quality of the treatment and to develop new treatment methods and source configurations. At the Nederland s Meetinstituut (NMi) a project is going on for the development of a primary standard for betadosimetry. With this standard, dose and dose distributions of β-sources as used in brachytherapy can be measured in terms of absorbed dose to water. The primary standard is based on an extrapolation chamber. The extrapolation chamber will become part of a quality assurance system in Dutch hospitals for endovascular brachytherapy sources. The quality assurance system will further consist of transfer standards like well-type ionisation chambers, plastic scintillator systems and radiochromic film dosimetry. Apart from the endovascular sources the extrapolation chamber will be used to characterize ophthalmic applicators

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

    International Nuclear Information System (INIS)

    Luvizotto, Jessica

    2015-01-01

    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)

  12. High dose-rate brachytherapy source position quality assurance using radiochromic film

    International Nuclear Information System (INIS)

    Evans, M.D.C.; Devic, S.; Podgorsak, E.B.

    2007-01-01

    Traditionally, radiographic film has been used to verify high-dose-rate brachytherapy source position accuracy by co-registering autoradiographic and diagnostic images of the associated applicator. Filmless PACS-based clinics that do not have access to radiographic film and wet developers may have trouble performing this quality assurance test in a simple and practical manner. We describe an alternative method for quality assurance using radiochromic-type film. In addition to being easy and practical to use, radiochromic film has some advantages in comparison with traditional radiographic film when used for HDR brachytherapy quality assurance

  13. Concomitant chemoradiotherapy with high dose rate brachytherapy ...

    African Journals Online (AJOL)

    Concomitant chemoradiotherapy with high dose rate brachytherapy as a definitive treatment modality for locally advanced cervical cancer. T Refaat, A Elsaid, N Lotfy, K Kiel, W Small Jr, P Nickers, E Lartigau ...

  14. Comparison of radiation shielding requirements for HDR brachytherapy using 169Yb and 192Ir sources

    International Nuclear Information System (INIS)

    Lymperopoulou, G.; Papagiannis, P.; Sakelliou, L.; Georgiou, E.; Hourdakis, C. J.; Baltas, D.

    2006-01-01

    169 Yb has received a renewed focus lately as an alternative to 192 Ir sources for high dose rate (HDR) brachytherapy. Following the results of a recent work by our group which proved 169 Yb to be a good candidate for HDR prostate brachytherapy, this work seeks to quantify the radiation shielding requirements for 169 Yb HDR brachytherapy applications in comparison to the corresponding requirements for the current 192 Ir HDR brachytherapy standard. Monte Carlo simulation (MC) is used to obtain 169 Yb and 192 Ir broad beam transmission data through lead and concrete. Results are fitted to an analytical equation which can be used to readily calculate the barrier thickness required to achieve a given dose rate reduction. Shielding requirements for a HDR brachytherapy treatment room facility are presented as a function of distance, occupancy, dose limit, and facility workload, using analytical calculations for both 169 Yb and 192 Ir HDR sources. The barrier thickness required for 169 Yb is lower than that for 192 Ir by a factor of 4-5 for lead and 1.5-2 for concrete. Regarding 169 Yb HDR brachytherapy applications, the lead shielding requirements do not exceed 15 mm, even in highly conservative case scenarios. This allows for the construction of a lead door in most cases, thus avoiding the construction of a space consuming, specially designed maze. The effects of source structure, attenuation by the patient, and scatter conditions within an actual treatment room on the above-noted findings are also discussed using corresponding MC simulation results

  15. Brachytherapy for breast cancer

    International Nuclear Information System (INIS)

    Spikalovas, V.; Mudenas, A.; Karoesiene, E.; Mickevicius, R.

    1996-01-01

    In 1987-1995 a total of 347 patients with breast cancer underwent interstitial treatment. Two methods of irradiation were applied. 1. When patients refused surgery, external radiotherapy was given followed by implant radiotherapy for a dose of 20-30 Gy. Needle sources were applied for treatment with an increasing activity on the ends. The application of special template devices made it possible to implant radioactive sources in a strictly pre-set geometry. This allowed to place the sources in the necessary geometry for the whole course of irradiation. Dosimetric planning was performed in Gray-equivalents to a selected isodose curve mostly 85%. Treatment time was 20-50 hours. 2. In cases when the tumour was localized in the medial quadrant of breast, interstitial therapy was applied to the parasternal lymph nodes. During mastectomy catheters were placed in a. thoracica interna of the corresponding side. On the first or second postoperative day flexible radioactive sources were inserted into catheters. Their active length was 10-12 cm. Irradiation dose at a distance of 2 cm from the centre of source was 40-45 Gy. Results: There was minimum radiation effect on the adjusting organs and tissues. Local recurrence of tumour in the region of irradiation was in 6 patients. Conclusions: The application of interstitial radiotherapy in treatment of breast cancer is effective and the results of radiation treatment are encouraging

  16. Standardization of prostate brachytherapy treatment plans

    International Nuclear Information System (INIS)

    Ove, Roger; Wallner, Kent; Badiozamani, Kas; Korjsseon, Tammy; Sutlief, Steven

    2001-01-01

    applied to 5 patients each from the 20- to 30-cc group and the 40- to 50-cc group. Using the standard plan designed for the 30- to 40-cc group, the TMs were closer to 10 mm than to 5 mm for the smaller volume glands and too small for the larger volume ones, assuming an ideal margin of 5 mm. Conclusion: The application of standardized plans to prostate brachytherapy is feasible. Stratifying the volume in 10-cc intervals appears to be adequate, suggesting that the majority of cases appropriate for treatment with brachytherapy might be treated with three standard plans. While the authors believe that the use of a limited number of standard treatment plans is feasible, practical, and medically acceptable, it should be emphasized that the use of a standard plan should always be previewed by computer-aided application to the particular patient's planning images

  17. Individualised 3D printed vaginal template for MRI guided brachytherapy in locally advanced cervical cancer

    DEFF Research Database (Denmark)

    Lindegaard, Jacob Christian; Lænsø Madsen, Mads; Hansen, Anders Traberg

    2016-01-01

    Intracavitary–interstitial applicators for MRI guided brachytherapy are becoming increasingly important in locally advanced cervical cancer. The 3D printing technology enables a versatile method for obtaining a high degree of individualisation of the implant. Our clinical workflow is presented...

  18. The use of disposable vascular catheters in interstitial brachytherapy of skin cancers

    International Nuclear Information System (INIS)

    Daly, N.J.; Malissard, L.; Douchez, J.; Combes, P.F.

    1978-01-01

    Technical improvements dealing with interstitial brachytherapy (Ir 192 ) of skin cancers are presented. Fine disposable plastic tubes fitted with mandril, which allow loading of light radioactive material in any case are used. Short term results are discussed according to 101 applications [fr

  19. Implementation of the technique of partial irradiation accelerated the breast with high doses (HDR) brachytherapy

    International Nuclear Information System (INIS)

    Molina Lopez, M. Y.; Pardo Perez, E.; Castro Novais, J.; Martinez Ortega, J.; Ruiz Maqueda, S.; Cerro Penalver, E. del

    2013-01-01

    The objective of this work is presents procedure carried out in our Centre for the implementation of the accelerated partial breast irradiation (APBI, accelerated partial-breast irradiation) with high-rate brachytherapy (HDR), using plastic tubes as applicators. Carried out measures, the evaluation of the dosimetric parameters analyzing and presenting the results. (Author)

  20. Evanescent field characterisation for a d-shaped optical fibre using scanning near-field optical microscopy

    International Nuclear Information System (INIS)

    Huntington, S.T.; Nugent, K.A.; Roberts, A.; Mulvaney, P.; Lo, K.M.

    1997-01-01

    Scanning near field optical microscopy is used to measure the evanescent filed and mode profile of a Ge-doped D-shaped optical fibre. The structure of the fibre is determined by differential etching followed by an investigation of the resultant topography with an atomic force microscope. This information is then used to theoretically model the expected behaviour of the fibre and it is shown that the theoretically model the expected behaviour of the fibre and it is shown that the theoretical results are in excellent agreement with the experimentally observed fields

  1. Brachytherapy Using Elastin-Like Polypeptides with (131)I Inhibit Tumor Growth in Rabbits with VX2 Liver Tumor.

    Science.gov (United States)

    Liu, Xinpei; Shen, Yiming; Zhang, Xuqian; Lin, Rui; Jia, Qiang; Chang, Yixiang; Liu, Wenge; Liu, Wentian

    2016-10-01

    Brachytherapy is a targeted type of radiotherapy utilized in the treatment of cancers. Elastin-like polypeptides are a unique class of genetically engineered peptide polymers that have several attractive properties for brachytherapy. To explore the feasibility and application of brachytherapy for VX2 liver tumor using elastin-like polypeptides with (131)I so as to provide reliable experimental evidence for a new promising treatment of liver cancer. Elastin-like polypeptide as carrier was labeled with (131)I using the iodogen method. Ten eligible rabbits with VX2 liver tumor were randomly divided into the treatment group (n = 5) and control group (n = 5). The treatment group received brachytherapy using elastin-like polypeptide with (131)I, and in the control group, elastin-like polypeptide was injected into the VX2 liver tumor as a control. Periodic biochemical and imaging surveillances were required to assess treatment efficacy. The stability of elastin-like polypeptide with (131)I in vitro was maintained at over 96.8 % for 96 h. Biochemistry and imaging indicated brachytherapy using elastin-like polypeptide with (131)I for liver tumor can improve liver function and inhibit tumor growth (P Elastin-like polypeptide can be an ideal carrier of (131)I and have high labeling efficiency, radiochemical purity and stability. Brachytherapy using elastin-like polypeptide with (131)I for liver tumor is a useful therapy that possesses high antitumor efficacy advantages.

  2. Brachytherapy reconstruction using orthogonal scout views from the CT

    International Nuclear Information System (INIS)

    Perez, J.; Lliso, F.; Carmona, V.; Bea, J.; Tormo, A.; Petschen, I.

    1996-01-01

    Introduction: CT assisted brachytherapy planning is demonstrating to have great advantages as external RT planning does. One of the problems we have found in this approach with the conventional gynecological Fletcher applicators is the high amount of artefacts (ovoids with rectal and vessical protections) in the CT slice. We have introduced a reconstruction method based on scout views in order to avoid this problem, allowing us to perform brachytherapy reconstruction completely CT assisted. We use a virtual simulation chain by General Electric Medical Systems. Method and discussion: Two orthogonal scout views (0 and 90 tube positions) are performed. The reconstruction method takes into account the virtual position of the focus and the fact that there is only divergence in the transverse plane. Algorithms developed for sources as well as for reference points localisation (A, B, lymphatic Fletcher trapezoid, pelvic wall, etc.) are presented. This method has the following practical advantages: the porte-cassette is not necessary, the image quality can be improved (it is very helpful in pelvic lateral views that are critical in conventional radiographs), the total time to get the data is smaller than for conventional radiographs (reduction of patient motion effects) and problems that appear in CT-slice based reconstruction in the case of strongly curved intrauterine applicators are avoided. Even though the resolution is smaller than in conventional radiographs it is good enough for brachytherapy. Regarding the CT planning this method presents the interesting feature that the co-ordinate system is the same for the reconstruction process that for the CT-slices set. As the application can be reconstructed from scout views and the doses can be evaluated on CT slices it is easier to correlate the dose values obtained for the traditional points with those provided by the CT information

  3. Novel prostate brachytherapy technique: Improved dosimetric and clinical outcome

    International Nuclear Information System (INIS)

    Nobes, Jenny P.; Khaksar, Sara J.; Hawkins, Maria A.; Cunningham, Melanie J.; Langley, Stephen E.M.; Laing, Robert W.

    2008-01-01

    Purpose: Erectile dysfunction following prostate brachytherapy is reported to be related to dose received by the penile bulb. To minimise this, whilst preserving prostate dosimetry, we have developed a technique for I-125 seed brachytherapy using both stranded seeds and loose seeds delivered with a Mick applicator, and implanted via the sagittal plane on trans-rectal ultrasound. Materials and methods: Post-implant dosimetry and potency rates were compared in 120 potent patients. In Group 1, 60 patients were treated using a conventional technique of seeds implanted in a modified-uniform distribution. From January 2005, a novel technique was developed using stranded seeds peripherally and centrally distributed loose seeds implanted via a Mick applicator (Group 2). The latter technique allows greater flexibility when implanting the seeds at the apex. Each patient was prescribed a minimum peripheral dose of 145 Gy. No patients received external beam radiotherapy or hormone treatment. There was no significant difference in age or pre-implant potency score (mean IIEF-5 score 22.4 vs. 22.6, p = 0.074) between the two groups. Results: The new technique delivers lower penile bulb doses (D 25 as %mPD - Group 1: 61.2 ± 35.7, Group 2: 29.7 ± 16.0, p 50 as %mPD - Group 1: 45.8 ± 26.9, Group 2: 21.4 ± 11.7, p 90 - Group 1: 147 Gy ± 21.1, Group 2: 155 Gy ± 16.7, p = 0.03). At 2 years, the potency rate was also improved: Group 1: 61.7%; Group 2: 83.3% (p = 0.008). Conclusions: In this study, the novel brachytherapy technique using both peripheral stranded seeds and central loose seeds delivered via a Mick applicator results in a lower penile bulb dose whilst improving prostate dosimetry, and may achieve higher potency rates

  4. Clinical feasibility of combined intracavitary/interstitial brachytherapy in locally advanced cervical cancer employing MRI with a tandem/ring applicator in situ and virtual preplanning of the interstitial component

    International Nuclear Information System (INIS)

    Fokdal, Lars; Tanderup, Kari; Hokland, Steffen Bjerre; Røhl, Lisbeth; Pedersen, Erik Morre; Nielsen, Søren Kynde; Paludan, Merete; Lindegaard, Jacob Christian

    2013-01-01

    Purpose: To investigate the reproducibility of virtually planned needles, changes in DVH parameters and clinical feasibility of combined intracavitary/interstitial (IC/IS) pulsed dose rate brachytherapy (PDR-BT) for locally advanced cervical cancer based on 3D MRI preplanning. Material and methods: Fifty-eight consecutively patients accrued in the EMBRACE study were included. Treatment was initiated with external beam radiotherapy and cisplatin. Three BT implants and MRI with the applicator in situ were performed in all patients, i.e. week 5 (BT0), week 6 (BT1) and week 7 (BT2) of the treatment. BT0 was only used for preplanning of subsequent implantations, whereas BT1 and BT2 comprised 2 equal sized fractions of PDR BT. Results: Based on BT0, 24 patients (41%) were selected for a combined IC/IS implant at BT1 and BT2. Patients treated with IC/IS BT had significantly larger tumours compared with patients treated with IC BT only (p < 0.03). Additional time in general anaesthesia for the IC/IS component was on average 16 min. The number of preplanned virtual needles was 5.3 ± 2.7 compared to 5.3 ± 2.9 and 5.4 ± 3.0 needles implanted at BT1 and BT2, respectively (p = 0.72). Planned needle implantation depth was 33 ± 15 mm compared to 30 ± 10 mm at BT1 and 29 ± 11 mm at BT2 (p = 0.04). In the 24 patients selected for IC/IS BT both the virtual IC/IS plan (BT0) and the actually delivered plan (BT1 + BT2) significantly increased D90 and D100 for HR CTV (p < 0.01) and reduced D2cc for sigmoid (p < 0.01) and bowel (p = 0.04) compared to the optimised IC preplan (BT0). IC/IS BT was only associated with minor morbidity, which was resolved at a 3-month follow up. Conclusion: Combined IC/IS BT based on full 3D MRI preplanning is clinically feasible. The virtual preplanned needle positions are reproducible at subsequent BT applications leading to significantly improved DVH parameters and a clinically feasible and fast implant procedure

  5. Intestinal morphological effect of brachytherapy of low rate of dose, administrated in therapeutic form and its clinical manifestations in uterine cervix tumors

    International Nuclear Information System (INIS)

    Mendoza, Carmen; Contreras, Manuel

    2005-01-01

    Brachytherapy is effective to eradicate cancer in the cervix, in order to obtain the control of disease we use high dose with vesical and rectum toxicity. The objective is to investigate if brachytherapy by itself is the cause of intestinal damage, to know in addition if the intensity of the clinic manifestations is in direct relation to the given radiation dose and this gets worse when it is received in several applications. Hypothesis: The intensity of the radiation with brachytherapy of low rate of dose is proportional to the degree of clinical manifestations and morphologic damage of the intestine. A prospective analysis was made inpatients with cancer of cervix from september 2000 to june 2004. Each patient who enters to the department of brachytherapy of the hospital must be done laboratory examination that includes plaque and coagulation test before being accepted. We use the clinical card and a table in order to register data concerning teletherapy, implants of brachytherapy of low rate of dose, symptoms of intestinal toxicity and details of colonoscopia. Subsequent to the hospitable discharge the patient is sent to gastroenterology for clinical evaluation and to realize colonoscopia. From september 2000 to june 2004, 540 patients entered, 80 patients (15%) displayed intestinal manifestations, all received teletherapy and brachytherapy, nobody else received brachytherapy in exclusive form and only one patient (0.1%) received the total of the dose in 2 applications. The equipment of teletherapy Primus with energy of 6 and 18 Mv and implants of brachytherapy Manchester were used (70/55 patients). 79 (98%) patients received dose between 85-75 Gy in one single application, 58 (72%) received the total of the dose to the tumor, 21 (26%) in vaginal mucosa. Discussion: Brachytherapy is the cause of the damages in the intestinal mucosa. (The author)

  6. Medical physics aspects of ophthalmic brachytherapy

    International Nuclear Information System (INIS)

    Sharma, S.D.; Shanta, A.; Palani Selvam, T.; Tripathi, U.B.; Bhatt, B.C.

    2004-11-01

    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 90 Sr/ 90 Y 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 125 I seed sources by the Radiopharmaceuticals Division, BARC. This report presents a brief description on the clinical, dosimetry and radiation safety aspects of 90 Sr/ 90 Y and 106 Ru/ 106 Rh beta ray and 125 I 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 90 Sr/ 90 Y and 106 Ru/ 106 Rh beta and 125 I gamma ophthalmic plaques are given in Section II and Section III, respectively. Section IV contains the single seed dosimetry data of BARC OcuProsta 125 I seed as well as dosimetry data of typical eye plaques loaded with BARC OcuProsta 125 I 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)

  7. Acute vasculitis after endovascular brachytherapy

    International Nuclear Information System (INIS)

    Fajardo L-G, Luis F.; Prionas, Stavros D.; Kaluza, Grzegorz L.; Raizner, Albert E.

    2002-01-01

    Purpose: Angioplasty effectively relieves coronary artery stenosis but is often followed by restenosis. Endovascular radiation (β or γ) at the time of angioplasty prevents restenosis in a large proportion of vessels in swine (short term) and humans (short and long term). Little information is available about the effects of this radiation exposure beyond the wall of the coronary arteries. Methods and Materials: Samples were obtained from 76 minipigs in the course of several experiments designed to evaluate endovascular brachytherapy: 76 of 114 coronary arteries and 6 of 12 iliac arteries were exposed to endovascular radiation from 32 P sources (35 Gy at 0.5 mm from the intima). Two-thirds of the vessels had angioplasty or stenting. The vessels were systematically examined either at 28 days or at 6 months after radiation. Results: We found an unexpected lesion: acute necrotizing vasculitis in arterioles located ≤2.05 mm from the target artery. It was characterized by fibrinoid necrosis of the wall, often associated with lymphocytic exudates or thrombosis. Based on the review of perpendicular sections of tissue samples, the arterioles had received between 6 and 40 Gy. This arteriolar vasculitis occurred at 28 days in samples from 51% of irradiated coronary arteries and 100% of irradiated iliac arteries. By 6 months, the incidence of acute vasculitis decreased to 24% around the coronary arteries. However, at that time, healing vasculitis was evident, often with luminal narrowing, in 46% of samples. Vasculitis was not seen in any of 44 samples from unirradiated vessels (0%) and had no relation to angioplasty, stenting, or their sequelae. This radiation-associated vasculitis in the swine resembles the localized lymphocytic vasculitis that we have reported in tissues of humans exposed to external radiation. On the other hand, it is quite different from the various types of systemic vasculitis that occur in nonirradiated humans. Conclusion: Endoarterial brachytherapy

  8. Multimodal and synthetic aperture approach to full-field 3D shape and displacement measurements

    Science.gov (United States)

    Kujawińska, M.; Sitnik, R.

    2017-08-01

    Recently most of the measurement tasks in industry, civil engineering and culture heritage applications require archiving, characterization and monitoring of 3D objects and structures and their performance under changing conditions. These requirements can be met if multimodal measurement (MM) strategy is applied. It rely on effective combining structured light method and 3D digital image correlation with laser scanning/ToF, thermal imaging, multispectral imaging and BDRF measurements. In the case of big size and/or complicated objects MM have to be combined with hierarchical or synthetic aperture (SA) measurements. The new solutions in MM and SA strategies are presented and their applicability is shown at interesting cultural heritage and civil engineering applications.

  9. Removal of jitter noise in 3D shape recovery from image focus by using Kalman filter.

    Science.gov (United States)

    Jang, Hoon-Seok; Muhammad, Mannan Saeed; Choi, Tae-Sun

    2018-02-01

    In regard to Shape from Focus, one critical factor impacting system application is mechanical vibration of the translational stage causing jitter noise along the optical axis. This noise is not detectable by simply observing the image. However, when focus measures are applied, inaccuracies in the depth occur. In this article, jitter noise and focus curves are modeled by Gaussian distribution and quadratic function, respectively. Then Kalman filter is designed and applied to eliminate this noise in the focus curves, as a post-processing step after the focus measure application. Experiments are implemented with simulated objects and real objects to show usefulness of proposed algorithm. © 2017 Wiley Periodicals, Inc.

  10. A method to combine three dimensional dose distributions for external beam and brachytherapy radiation treatments for gynecological neoplasms

    International Nuclear Information System (INIS)

    Narayana, V.; Sahijdak, W.M.; Orton, C.G.

    1997-01-01

    Purpose: Radiation treatment of gynecological neoplasms, such as cervical carcinoma, usually combines external radiation therapy with one or more intracavitary brachytherapy applications. Although the dose from external beam radiation therapy and brachytherapy can be calculated and displayed in 3D individually, the dose distributions are not combined. At most, combined point doses are calculated for select points using various time-dose models. In this study, we present a methodology to combine external beam and brachytherapy treatments for gynecological neoplasms. Material and Methods: Three dimensional bio-effect treatment planning to obtain complication probability has been outlined. CT scans of the patient's pelvis with the gynecological applicator in place are used to outline normal tissue and tumor volumes. 3D external beam and brachytherapy treatment plans are developed separately and an external beam dose matrix and a brachytherapy dose matrix was calculated. The dose in each voxel was assumed to be homogeneous. The physical dose in each voxel of the dose matrix was then converted into extrapolated response dose (ERD) based on the linear quadratic model that accounts for the dose per fraction, number of fractions, dose rate, and complete or incomplete repair of sublethal damage (time between fractions). The net biological dose delivered was obtained by summing the ERD grids from external beam and brachytherapy since there was complete repair of sublethal damage between external beam and brachytherapy treatments. The normal tissue complication probability and tumor control probability were obtained using the biological dose matrix based on the critical element model. Results: The outlined method of combining external beam and brachytherapy treatments was implemented on gynecological treatments using an applicator for brachytherapy treatments. Conclusion: Implementation of the biological dose calculation that combine different modalities is extremely useful

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

    International Nuclear Information System (INIS)

    Ladeia, F.T.; Novaes, P.E.R.S.; Pereira, A.J.; Peres, O.; Camargo, B.; Bianchi, A.

    1988-01-01

    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)

  12. Radiological protection of patients in brachytherapy

    International Nuclear Information System (INIS)

    Sacc, Ricardo; Herrero, Flavia

    2008-01-01

    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

  13. Auger Electron Therapy And Brachytherapy Tumor Treatment

    International Nuclear Information System (INIS)

    Laster, B.H.; Shani, G.

    2002-01-01

    Auger Electron Therapy (AET) is a binary approach for improving cancer radiotherapy. It involves the selective targeting of an atom to tumor cells using physiological pathway. The atom is then irradiated by a specific radiation that produces secondary radiation called Auger electrons. One of the problems associated with the clinical application of AET, is that the energy of the photons required for stimulating photoelectric absorption in most of the available high Z target atoms, is too low to achieve penetration through normal surrounding tissues to the depth of the tumor, when an external source is used. The solution is therefore the use of a brachytherapy technique. There are two other problems associated with the use of radiation as a cancer treatment. The first is the limitation on radiation dose to the normal tissue within the treatment volume. The second problem is the limitation imposed by the miniscule size of the critical target of the cell, namely the DNA (0.25% of the cell mass). The solution to the first problem can be achieved by using the brachytherapy technique. The second problem can be resolved by placing the radiation source in close position to the DNA. AET, as we apply it, provides the two solutions to the two problems. When a photon is absorbed by an electron in the K or L shell of an high Z atom, the electron is ejected from the atom, creating a vacancy in the shell. This vacancy is immediately filled with an electron from an upper shell. The energy difference between the two shells is sometimes emitted as an x-ray, however, frequently the energy is transferred to an outer shell electron that is emitted as an Auger electron. These electrons are emitted at energies of up to ∼30 keV and therefore have a very short range in the cell. They will deposit all their energy within 20-30 nm from the point of emission. i.e. all the energy is deposited in the DNA. In our work indium is used as the high Z atom

  14. A novel methodology to model the cooling processes of packed horticultural produce using 3D shape models

    Science.gov (United States)

    Gruyters, Willem; Verboven, Pieter; Rogge, Seppe; Vanmaercke, Simon; Ramon, Herman; Nicolai, Bart

    2017-10-01

    Freshly harvested horticultural produce require a proper temperature management to maintain their high economic value. Towards this end, low temperature storage is of crucial importance to maintain a high product quality. Optimizing both the package design of packed produce and the different steps in the postharvest cold chain can be achieved by numerical modelling of the relevant transport phenomena. This work presents a novel methodology to accurately model both the random filling of produce in a package and the subsequent cooling process. First, a cultivar-specific database of more than 100 realistic CAD models of apple and pear fruit is built with a validated geometrical 3D shape model generator. To have an accurate representation of a realistic picking season, the model generator also takes into account the biological variability of the produce shape. Next, a discrete element model (DEM) randomly chooses surface meshed bodies from the database to simulate the gravitational filling process of produce in a box or bin, using actual mechanical properties of the fruit. A computational fluid dynamics (CFD) model is then developed with the final stacking arrangement of the produce to study the cooling efficiency of packages under several conditions and configurations. Here, a typical precooling operation is simulated to demonstrate the large differences between using actual 3D shapes of the fruit and an equivalent spheres approach that simplifies the problem drastically. From this study, it is concluded that using a simplified representation of the actual fruit shape may lead to a severe overestimation of the cooling behaviour.

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

    International Nuclear Information System (INIS)

    Yamazaki, Hideya; Inoue, Takehiro; Yoshida, Ken; Yoshioka, Yasuo; Shimizutani, Kimishige; Inoue, Toshihiko; Furukawa, Souhei; Kakimoto, Naoya

    2003-01-01

    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)

  16. SU-F-BRA-04: Prostate HDR Brachytherapy with Multichannel Robotic System

    International Nuclear Information System (INIS)

    Joseph, F Maria; Podder, T; Yu, Y

    2015-01-01

    Purpose: High-dose-rate (HDR) brachytherapy is gradually becoming popular in treating patients with prostate cancers. However, placement of the HDR needles at desired locations into the patient is challenging. Application of robotic system may improve the accuracy of the clinical procedure. This experimental study is to evaluate the feasibility of using a multichannel robotic system for prostate HDR brachytherapy. Methods: In this experimental study, the robotic system employed was a 6-DOF Multichannel Image-guided Robotic Assistant for Brachytherapy (MIRAB), which was designed and fabricated for prostate seed implantation. The MIRAB has the provision of rotating 16 needles while inserting them. Ten prostate HDR brachytherapy needles were simultaneously inserted using MIRAB into a commercially available prostate phantom. After inserting the needles into the prostate phantom at desired locations, 2mm thick CT slices were obtained for dosimetric planning. HDR plan was generated using Oncetra planning system with a total prescription dose of 34Gy in 4 fractions. Plan quality was evaluated considering dose coverage to prostate and planning target volume (PTV), with 3mm margin around prostate, as well as the dose limit to the organs at risk (OARs) following the American Brachytherapy Society (ABS) guidelines. Results: From the CT scan, it is observed that the needles were inserted straight into the desired locations and they were adequately spaced and distributed for a clinically acceptable HDR plan. Coverage to PTV and prostate were about 91% (V100= 91%) and 96% (V100=96%), respectively. Dose to 1cc of urethra, rectum, and bladder were within the ABS specified limits. Conclusion: The MIRAB was able to insert multiple needles simultaneously into the prostate precisely. By controlling the MIRAB to insert all the ten utilized needles into the prostate phantom, we could achieve the robotic HDR brachytherapy successfully. Further study for assessing the system

  17. 10 CFR 35.2406 - Records of brachytherapy source accountability.

    Science.gov (United States)

    2010-01-01

    ... 10 Energy 1 2010-01-01 2010-01-01 false Records of brachytherapy source accountability. 35.2406... Records of brachytherapy source accountability. (a) A licensee shall maintain a record of brachytherapy source accountability required by § 35.406 for 3 years. (b) For temporary implants, the record must...

  18. 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 Brachytherapy sources accountability. (a) A licensee shall maintain accountability at all times... area. (c) A licensee shall maintain a record of the brachytherapy source accountability in accordance...

  19. Endovascular brachytherapy to prevent restenosis after angioplasty

    International Nuclear Information System (INIS)

    Wohlgemuth, W.A.; Bohndorf, K.

    2003-01-01

    Endovascular radiotherapy is the first effective prophylaxis of restenosis after percutaneous transluminal angioplasty (PTA) and stenting. The FDA recently approved two devices for the delivery of intracoronary radiation following coronary artery stenting. Published multicenter, double-blind, randomized trials of intracoronary radiation therapy report good results for preventing in-stent restenosis, while the data for the peripheral circulation are still inconclusive. Beta-emitters are easier applicable and probably also safer, whereas gamma-emitters have been more extensively evaluated clinically so far. Primary indication for endovascular brachytherapy are patients at high risk for restenosis, such as previous restenoses, in-stent hyperplasia, long stented segment, long PTA lesion, narrow residual vascular lumen and diabetes. Data from coronary circulation suggest a safety margin of at least 4 to 10 mm at both ends of the angioplastic segment to avoid edge restenosis. To prevent late thrombosis of the treated coronary segment, antiplatelet therapy with clopidogrel and aspirin are recommended for at least 6 months after PTA and for 12 months after a newly implanted stent. An established medication regimen after radiotherapy of peripheral arteries is still lacking. (orig.) [de

  20. Aerial 3D display by use of a 3D-shaped screen with aerial imaging by retro-reflection (AIRR)

    Science.gov (United States)

    Kurokawa, Nao; Ito, Shusei; Yamamoto, Hirotsugu

    2017-06-01

    The purpose of this paper is to realize an aerial 3D display. We design optical system that employs a projector below a retro-reflector and a 3D-shaped screen. A floating 3D image is formed with aerial imaging by retro-reflection (AIRR). Our proposed system is composed of a 3D-shaped screen, a projector, a quarter-wave retarder, a retro-reflector, and a reflective polarizer. Because AIRR forms aerial images that are plane-symmetric of the light sources regarding the reflective polarizer, the shape of the 3D screen is inverted from a desired aerial 3D image. In order to expand viewing angle, the 3D-shaped screen is surrounded by a retro-reflector. In order to separate the aerial image from reflected lights on the retro- reflector surface, the retro-reflector is tilted by 30 degrees. A projector is located below the retro-reflector at the same height of the 3D-shaped screen. The optical axis of the projector is orthogonal to the 3D-shaped screen. Scattered light on the 3D-shaped screen forms the aerial 3D image. In order to demonstrate the proposed optical design, a corner-cube-shaped screen is used for the 3D-shaped screen. Thus, the aerial 3D image is a cube that is floating above the reflective polarizer. For example, an aerial green cube is formed by projecting a calculated image on the 3D-shaped screen. The green cube image is digitally inverted in depth by our developed software. Thus, we have succeeded in forming aerial 3D image with our designed optical system.

  1. SU-G-201-12: Investigation of Beta-Emitter 90Sr-90Y Dose Distribution Using Gafchromic EBT3 Film for Application On Conformal Skin Brachytherapy Device

    Energy Technology Data Exchange (ETDEWEB)

    Ferreira, C; Johnson, D; Ahmad, S [University of Oklahoma Health Sciences Center, Oklahoma City, OK (United States); Rasmussen, K [University of Texas HSC SA, San Antonio, TX (United States); Jung, J [East Carolina University Greenville, NC (United States)

    2016-06-15

    Purpose: To investigate {sup 90}Sr-{sup 90}Y as a high dose rate (HDR) source for application in a conformal skin brachytherapy (CSBT) device. The CSBT device has been previously developed to provide patient specific treatment for small inoperable lesions and irregular surfaces. Methods: A popular beta emitter, {sup 90}Sr-{sup 90}Y was tested for feasibility in a CSBT device. A 1 cm diameter plaque was used to deliver dose to a solid water phantom containing EBT3 Gafchromic films arranged at the surface and perpendicular to it. Additionally, a 1 cm diameter 6 MeV electron beam was used to irradiate EBT3 film at 100 cm SSD with a 0.5 cm bolus. Films were digitized with an Epson Expression 10000 XL scanner and calibrated with a 6 MeV electron specific dose curve. Normalized percent depth doses (PDD) and dose profiles for both techniques were analyzed using ImageJ. Results: Dose distributions achieved with the {sup 90}Sr-{sup 90}Y sources were compared with those of external electron beam radiation therapy (EBRT). Penumbra (20%- 80%) for EBRT and 90Sr-90Y were 4.3 mm and 1.6 mm, respectively. PDD values of 50% (normalized to 2 mm) were 10.1 mm and 2.8 mm for electron and {sup 90}Sr-{sup 90}Y, respectively. Flatness (80% of the central beam profile) was 14.1% at a 5 mm depth for EBRT and 4.0% at surface for the {sup 90}Sr-{sup 90}Y. Conclusion: As expected, the PDDs of {sup 90}Sr-{sup 90}Y in water are shallower than that of external electron beams for the same field size. {sup 90}Sr-{sup 90}Y can be used in CSBT to provide patient specific treatment where shallower depth doses than that provided by electron external beams may be required: e.g. eyelids, nose, lips, ears, etc. The customizability of EBRT could be replicated by using multiple adjacent {sup 90}Sr-{sup 90}Y plaque placements.

  2. MO-D-BRD-01: Clinical Implementation of An Electronic Brachytherapy Program for the Skin

    International Nuclear Information System (INIS)

    Ouhib, Z.

    2015-01-01

    Electronic brachytherapy (eBT) has seen an insurgence of manufacturers entering the US market for use in radiation therapy. In addition to the established interstitial, intraluminary, and intracavitary applications of eBT, many centers are now using eBT to treat skin lesions. It is important for medical physicists working with electronic brachytherapy sources to understand the basic physics principles of the sources themselves as well as the variety of applications for which they are being used. The calibration of the sources is different from vendor to vendor and the traceability of calibrations has evolved as new sources came to market. In 2014, a new air-kerma based standard was introduced by the National Institute of Standards and Technology (NIST) to measure the output of an eBT source. Eventually commercial treatment planning systems should accommodate this new standard and provide NIST traceability to the end user. The calibration and commissioning of an eBT system is unique to its application and typically entails a list of procedural recommendations by the manufacturer. Commissioning measurements are performed using a variety of methods, some of which are modifications of existing AAPM Task Group protocols. A medical physicist should be familiar with the different AAPM Task Group recommendations for applicability to eBT and how to properly adapt them to their needs. In addition to the physical characteristics of an eBT source, the photon energy is substantially lower than from HDR Ir-192 sources. Consequently, tissue-specific dosimetry and radiobiological considerations are necessary when comparing these brachytherapy modalities and when making clinical decisions as a radiation therapy team. In this session, the physical characteristics and calibration methodologies of eBt sources will be presented as well as radiobiology considerations and other important clinical considerations. Learning Objectives: To understand the basic principles of electronic

  3. MO-D-BRD-03: Radiobiology and Commissioning of Electronic Brachytherapy for IORT

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, J. [Oregon Health & Science Univ (United States)

    2015-06-15

    Electronic brachytherapy (eBT) has seen an insurgence of manufacturers entering the US market for use in radiation therapy. In addition to the established interstitial, intraluminary, and intracavitary applications of eBT, many centers are now using eBT to treat skin lesions. It is important for medical physicists working with electronic brachytherapy sources to understand the basic physics principles of the sources themselves as well as the variety of applications for which they are being used. The calibration of the sources is different from vendor to vendor and the traceability of calibrations has evolved as new sources came to market. In 2014, a new air-kerma based standard was introduced by the National Institute of Standards and Technology (NIST) to measure the output of an eBT source. Eventually commercial treatment planning systems should accommodate this new standard and provide NIST traceability to the end user. The calibration and commissioning of an eBT system is unique to its application and typically entails a list of procedural recommendations by the manufacturer. Commissioning measurements are performed using a variety of methods, some of which are modifications of existing AAPM Task Group protocols. A medical physicist should be familiar with the different AAPM Task Group recommendations for applicability to eBT and how to properly adapt them to their needs. In addition to the physical characteristics of an eBT source, the photon energy is substantially lower than from HDR Ir-192 sources. Consequently, tissue-specific dosimetry and radiobiological considerations are necessary when comparing these brachytherapy modalities and when making clinical decisions as a radiation therapy team. In this session, the physical characteristics and calibration methodologies of eBt sources will be presented as well as radiobiology considerations and other important clinical considerations. Learning Objectives: To understand the basic principles of electronic

  4. SU-F-T-50: Evaluation of Monte Carlo Simulations Performance for Pediatric Brachytherapy Dosimetry

    Energy Technology Data Exchange (ETDEWEB)

    Chatzipapas, C; Kagadis, G [University Patras, Rion, Ahaia (Greece); Papadimitroulas, P [BET Solutions, Athens, Attiki (Greece); Loudos, G [Technological Educational Institute of Athens, Egaleo, Attiki (Greece); Papanikolaou, N [University of Texas HSC SA, San Antonio, TX (United States)

    2016-06-15

    Purpose: Pediatric tumors are generally treated with multi-modal procedures. Brachytherapy can be used with pediatric tumors, especially given that in this patient population low toxicity on normal tissues is critical as is the suppression of the probability for late malignancies. Our goal is to validate the GATE toolkit on realistic brachytherapy applications, and evaluate brachytherapy plans on pediatrics for accurate dosimetry on sensitive and critical organs of interest. Methods: The GATE Monte Carlo (MC) toolkit was used. Two High Dose Rate (HDR) 192Ir brachytherapy sources were simulated (Nucletron mHDR-v1 and Varian VS2000), and fully validated using the AAPM and ESTRO protocols. A realistic brachytherapy plan was also simulated using the XCAT anthropomorphic computational model .The simulated data were compared to the clinical dose points. Finally, a 14 years old girl with vaginal rhabdomyosarcoma was modelled based on clinical procedures for the calculation of the absorbed dose per organ. Results: The MC simulations resulted in accurate dosimetry in terms of dose rate constant (Λ), radial dose gL(r) and anisotropy function F(r,θ) for both sources.The simulations were executed using ∼1010 number of primaries resulting in statistical uncertainties lower than 2%.The differences between the theoretical values and the simulated ones ranged from 0.01% up to 3.3%, with the largest discrepancy (6%) being observed in the dose rate constant calculation.The simulated DVH using an adult female XCAT model was also compared to a clinical one resulting in differences smaller than 5%. Finally, a realistic pediatric brachytherapy simulation was performed to evaluate the absorbed dose per organ and to calculate DVH with respect to heterogeneities of the human anatomy. Conclusion: GATE is a reliable tool for brachytherapy simulations both for source modeling and for dosimetry in anthropomorphic voxelized models. Our project aims to evaluate a variety of pediatric

  5. Novel Use of the Contura for High Dose Rate Cranial Brachytherapy

    International Nuclear Information System (INIS)

    Scanderbeg, Daniel J.; Alksne, John F.; Lawson, Joshua D.; Murphy, Kevin T.

    2011-01-01

    A popular choice for treatment of recurrent gliomas was cranial brachytherapy using the GliaSite Radiation Therapy System. However, this device was taken off the market in late 2008, thus leaving a treatment void. This case study presents our experience treating a cranial lesion for the first time using a Contura multilumen, high-dose-rate (HDR) brachytherapy balloon applicator. The patient was a 47-year-old male who was diagnosed with a recurrent right frontal anaplastic oligodendroglioma. Previous radiosurgery made him a good candidate for brachytherapy. An intracavitary HDR balloon brachytherapy device (Contura) was placed in the resection cavity and treated with a single fraction of 20 Gy. The implant, treatment, and removal of the device were all completed without incident. Dosimetry of the device was excellent because the dose conformed very well to the target. V90, V100, V150, and V200 were 98.9%, 95.7%, 27.2, and 8.8 cc, respectively. This patient was treated successfully using the Contura multilumen balloon. Contura was originally designed for deployment in a postlumpectomy breast for treatment by accelerated partial breast irradiation. Being an intracavitary balloon device, its similarity to the GliaSite system makes it a viable replacement candidate. Multiple lumens in the device also make it possible to shape the dose delivered to the target, something not possible before with the GliaSite applicator.

  6. Novel use of the Contura for high dose rate cranial brachytherapy.

    Science.gov (United States)

    Scanderbeg, Daniel J; Alksne, John F; Lawson, Joshua D; Murphy, Kevin T

    2011-01-01

    A popular choice for treatment of recurrent gliomas was cranial brachytherapy using the GliaSite Radiation Therapy System. However, this device was taken off the market in late 2008, thus leaving a treatment void. This case study presents our experience treating a cranial lesion for the first time using a Contura multilumen, high-dose-rate (HDR) brachytherapy balloon applicator. The patient was a 47-year-old male who was diagnosed with a recurrent right frontal anaplastic oligodendroglioma. Previous radiosurgery made him a good candidate for brachytherapy. An intracavitary HDR balloon brachytherapy device (Contura) was placed in the resection cavity and treated with a single fraction of 20 Gy. The implant, treatment, and removal of the device were all completed without incident. Dosimetry of the device was excellent because the dose conformed very well to the target. V90, V100, V150, and V200 were 98.9%, 95.7%, 27.2, and 8.8 cc, respectively. This patient was treated successfully using the Contura multilumen balloon. Contura was originally designed for deployment in a postlumpectomy breast for treatment by accelerated partial breast irradiation. Being an intracavitary balloon device, its similarity to the GliaSite system makes it a viable replacement candidate. Multiple lumens in the device also make it possible to shape the dose delivered to the target, something not possible before with the GliaSite applicator. Copyright © 2011 American Association of Medical Dosimetrists. Published by Elsevier Inc. All rights reserved.

  7. HIGH-DOSE RATE BRACHYTHERAPY IN CARCINOMA CERVIX STAGE IIIB

    Directory of Open Access Journals (Sweden)

    Sathya Maruthavanan

    2016-07-01

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

  8. Artificial neural network based gynaecological image-guided adaptive brachytherapy treatment planning correction of intra-fractional organs at risk dose variation.

    Science.gov (United States)

    Jaberi, Ramin; Siavashpour, Zahra; Aghamiri, Mahmoud Reza; Kirisits, Christian; Ghaderi, Reza

    2017-12-01

    Intra-fractional organs at risk (OARs) deformations can lead to dose variation during image-guided adaptive brachytherapy (IGABT). The aim of this study was to modify the final accepted brachytherapy treatment plan to dosimetrically compensate for these intra-fractional organs-applicators position variations and, at the same time, fulfilling the dosimetric criteria. Thirty patients with locally advanced cervical cancer, after external beam radiotherapy (EBRT) of 45-50 Gy over five to six weeks with concomitant weekly chemotherapy, and qualified for intracavitary high-dose-rate (HDR) brachytherapy with tandem-ovoid applicators were selected for this study. Second computed tomography scan was done for each patient after finishing brachytherapy treatment with applicators in situ. Artificial neural networks (ANNs) based models were used to predict intra-fractional OARs dose-volume histogram parameters variations and propose a new final plan. A model was developed to estimate the intra-fractional organs dose variations during gynaecological intracavitary brachytherapy. Also, ANNs were used to modify the final brachytherapy treatment plan to compensate dosimetrically for changes in 'organs-applicators', while maintaining target dose at the original level. There are semi-automatic and fast responding models that can be used in the routine clinical workflow to reduce individually IGABT uncertainties. These models can be more validated by more patients' plans to be able to serve as a clinical tool.

  9. Three-dimensional tomosynthetic image restoration for brachytherapy source localization

    International Nuclear Information System (INIS)

    Persons, Timothy M.

    2001-01-01

    Tomosynthetic image reconstruction allows for the production of a virtually infinite number of slices from a finite number of projection views of a subject. If the reconstructed image volume is viewed in toto, and the three-dimensional (3D) impulse response is accurately known, then it is possible to solve the inverse problem (deconvolution) using canonical image restoration methods (such as Wiener filtering or solution by conjugate gradient least squares iteration) by extension to three dimensions in either the spatial or the frequency domains. This dissertation presents modified direct and iterative restoration methods for solving the inverse tomosynthetic imaging problem in 3D. The significant blur artifact that is common to tomosynthetic reconstructions is deconvolved by solving for the entire 3D image at once. The 3D impulse response is computed analytically using a fiducial reference schema as realized in a robust, self-calibrating solution to generalized tomosynthesis. 3D modulation transfer function analysis is used to characterize the tomosynthetic resolution of the 3D reconstructions. The relevant clinical application of these methods is 3D imaging for brachytherapy source localization. Conventional localization schemes for brachytherapy implants using orthogonal or stereoscopic projection radiographs suffer from scaling distortions and poor visibility of implanted seeds, resulting in compromised source tracking (reported errors: 2-4 mm) and dosimetric inaccuracy. 3D image reconstruction (using a well-chosen projection sampling scheme) and restoration of a prostate brachytherapy phantom is used for testing. The approaches presented in this work localize source centroids with submillimeter error in two Cartesian dimensions and just over one millimeter error in the third

  10. Visualization of the 3D shape of the articular cartilage of the femoral head from MR images

    International Nuclear Information System (INIS)

    Kubota, Tetsuya; Sato, Yoshinobu; Nakanishi, Katsuyuki

    1999-01-01

    This paper describes methods for visualizing the three-dimensional (3D) cartilage thickness distribution from MR images. Cartilage thickness is one of the most important factors in joint diseases. Although the evaluation of cartilage thickness has received considerable attention from orthopedic surgeons and radiologists, evaluation is usually performed based on visual analysis or measurements obtained using calipers on original MR images. Our aim is to employ computerized quantification of MR images for the evaluation of the cartilage thickness of the femoral head. First, we extract an ROI and interpolate all ROI images by sinc interpolation. Next, we extract cartilage regions from MR images using a 3D multiscale sheet filter. Finally, we reconstruct 3D shapes by summing the extracted cartilage regions. We investigate partial volume effects in this method using synthesized images, and show results for in vitro and in vivo MR images. (author)

  11. 3D-shape of objects with straight line-motion by simultaneous projection of color coded patterns

    Science.gov (United States)

    Flores, Jorge L.; Ayubi, Gaston A.; Di Martino, J. Matías; Castillo, Oscar E.; Ferrari, Jose A.

    2018-05-01

    In this work, we propose a novel technique to retrieve the 3D shape of dynamic objects by the simultaneous projection of a fringe pattern and a homogeneous light pattern which are both coded in two of the color channels of a RGB image. The fringe pattern, red channel, is used to retrieve the phase by phase-shift algorithms with arbitrary phase-step, while the homogeneous pattern, blue channel, is used to match pixels from the test object in consecutive images, which are acquired at different positions, and thus, to determine the speed of the object. The proposed method successfully overcomes the standard requirement of projecting fringes of two different frequencies; one frequency to extract object information and the other one to retrieve the phase. Validation experiments are presented.

  12. Physics and quality assurance for brachytherapy - Part II: Low dose rate and pulsed dose rate

    International Nuclear Information System (INIS)

    Williamson, Jeffrey F.

    1997-01-01

    Purpose: A number of recent developments have revitalized brachytherapy including remote afterloading, implant optimization, increasing use of 3D imaging, and advances in dose specification and basic dosimetry. However, the core physical principles underlying the classical methods of dose calculation and arrangement of multiple sources remain unchanged. The purpose of this course is to review these principles and their applications to low dose-rate interstitial and intracavitary brachytherapy. Emphasis will be placed upon the classical implant systems along with classical and modern methods of dose specification. The level of presentation is designed for radiation oncology residents and beginning clinical physicists. A. Basic Principles (1) Radium-substitute vs. low-energy sealed sources (2) Dose calculation principles (3) The mysteries of source strength specification revealed: mgRaEq, mCi and air-kerma strength B. Interstitial Brachytherapy (1) Target volume, implanted volume, dose specification in implants and implant optimization criteria (2) Classical implant systems: Manchester Quimby and Paris a) Application of the Manchester system to modern brachytherapy b) Comparison of classical systems (3) Permanent interstitial implants a) Photon energy and half life b) Dose specification and pre-operative planning (4) The alphabet soup of dose specification: MCD (mean central dose), minimum dose, MPD (matched peripheral dose), MPD' (minimum peripheral dose) and DVH (dose-volume histogram) quality indices C. Intracavitary Brachytherapy for Carcinoma of the Cervix (1) Basic principles a) Manchester System: historical foundation of U.S. practice patterns b) Principles of applicator design (2) Dose specification and treatment prescription a) mg-hrs, reference points, ICRU Report 38 reference volume -- Point A dose vs mg-hrs and IRAK (Integrated Reference Air Kerma) -- Tissue volume treated vs mg-hrs and IRAK b) Practical methods of treatment specification and prescription

  13. Physics and quality assurance for brachytherapy - Part II: Low dose rate and pulsed dose rate

    International Nuclear Information System (INIS)

    Williamson, Jeffrey F.

    1996-01-01

    Purpose: A number of recent developments have revitalized brachytherapy including remote afterloading, implant optimization, increasing use of 3D imaging, and advances in dose specification and basic dosimetry. However, the core physical principles underlying the classical methods of dose calculation and arrangement of multiple sources remain unchanged. The purpose of this course is to review these principles and their applications to low dose-rate interstitial and intracavitary brachytherapy. Emphasis will be placed upon the classical implant systems along with classical and modern methods of dose specification. The level of presentation is designed for radiation oncology residents and beginning clinical physicists. A. Basic Principles (1) Radium-substitute vs. low-energy sealed sources (2) Dose calculation principles (3) The mysteries of source strength specification revealed: mgRaEq, mCi and air-kerma strength B. Interstitial Brachytherapy (1) Target volume, implanted volume, dose specification in implants and implant optimization criteria (2) Classical implant systems: Manchester Quimby and Paris a) Application of the Manchester system to modern brachytherapy b) Comparison of classical systems (3) Permanent interstitial implants a) Photon energy and half life b) Dose specification and pre-operative planning (4) The alphabet soup of dose specification: MCD (mean central dose), minimum dose, MPD (matched peripheral dose), MPD' (minimum peripheral dose) and DVH (dose-volume histogram) quality indices C. Intracavitary Brachytherapy for Carcinoma of the Cervix (1) Basic principles a) Manchester System: historical foundation of U.S. practice patterns b) Principles of applicator design (2) Dose specification and treatment prescription a) mg-hrs, reference points, ICRU Report 38 reference volume --Point A dose vs mg-hrs and IRAK (Integrated Reference Air Kerma) --Tissue volume treated vs mg-hrs and IRAK b) Practical methods of treatment specification and prescription

  14. WE-A-17A-05: Differences in Applicator Configuration and Dwell Loading Between Standard and Image-Guided Tandem and Ring (T and R) HDR Brachytherapy

    Energy Technology Data Exchange (ETDEWEB)

    Damato, A; Cormack, R; Bhagwat, M; Buzurovic, I; Lee, L; Viswanathan, A [Brigham and Women' s Hospital, Boston, MA (United States)

    2014-06-15

    Purpose: To investigate differences in: (i) relative location of the tandem and the ring compared to a rigid standard applicator model; and (ii) relative loading and changes in loading pattern between standard and image-guided planning. Methods: All T and R insertions performed in 2013 in our institution under CT- or MR-guidance were analyzed. Standard plans were generated using library applicator models with a fixed relationship between ring and tandem, standardized uniform dwell loading and normalization to point A. The graphic plans and the associated standard-plan dwell configurations were compared: the rings were rigidly registered, and the residual tandem shift, rotation and maximum distance between plan tandem dwell and corresponding model tandem dwell were calculated. The normalization ratio (NR = the ratio of graphic versus standard-plan total reference air kerma [TRAK]), the general loading difference (GLD = the difference between graphic and standard ratios of the tandem versus the ring TRAK), and the percent standard deviation (SD% = SD/mean) of the tandem and the ring TRAK for the graphic plan (all standard-plans SD% = 0) were calculated. Results: 71 T and R were analyzed. Residual tandem shift, rotation and maximum corresponding dwell distance were 1.2±0.8mm (0.4±0.4mm lateral, 0.9±0.8mm craniocaudal, 0.4±0.3mm anterior-posterior), 2.3±1.9deg and 3.4±2.3mm. NR was 0.86±0.11 indicating a lower overall loading of the graphic compared to the standard plans. GLD was -0.12±0.16 indicating a modest increased ring loading relative to the tandem in the graphic plans. SD% was 2.1±1.6% for tandem and 2.8±1.9% for ring, indicating small deviations from uniform loading. Conclusion: Variability in the relative locations of the tandem and the ring necessitates the independent registration of each component model for accurate digitization. Our clinical experience suggests that graphically planned T and R results on average in a lower total dose to the

  15. WE-A-17A-05: Differences in Applicator Configuration and Dwell Loading Between Standard and Image-Guided Tandem and Ring (T and R) HDR Brachytherapy

    International Nuclear Information System (INIS)

    Damato, A; Cormack, R; Bhagwat, M; Buzurovic, I; Lee, L; Viswanathan, A

    2014-01-01

    Purpose: To investigate differences in: (i) relative location of the tandem and the ring compared to a rigid standard applicator model; and (ii) relative loading and changes in loading pattern between standard and image-guided planning. Methods: All T and R insertions performed in 2013 in our institution under CT- or MR-guidance were analyzed. Standard plans were generated using library applicator models with a fixed relationship between ring and tandem, standardized uniform dwell loading and normalization to point A. The graphic plans and the associated standard-plan dwell configurations were compared: the rings were rigidly registered, and the residual tandem shift, rotation and maximum distance between plan tandem dwell and corresponding model tandem dwell were calculated. The normalization ratio (NR = the ratio of graphic versus standard-plan total reference air kerma [TRAK]), the general loading difference (GLD = the difference between graphic and standard ratios of the tandem versus the ring TRAK), and the percent standard deviation (SD% = SD/mean) of the tandem and the ring TRAK for the graphic plan (all standard-plans SD% = 0) were calculated. Results: 71 T and R were analyzed. Residual tandem shift, rotation and maximum corresponding dwell distance were 1.2±0.8mm (0.4±0.4mm lateral, 0.9±0.8mm craniocaudal, 0.4±0.3mm anterior-posterior), 2.3±1.9deg and 3.4±2.3mm. NR was 0.86±0.11 indicating a lower overall loading of the graphic compared to the standard plans. GLD was -0.12±0.16 indicating a modest increased ring loading relative to the tandem in the graphic plans. SD% was 2.1±1.6% for tandem and 2.8±1.9% for ring, indicating small deviations from uniform loading. Conclusion: Variability in the relative locations of the tandem and the ring necessitates the independent registration of each component model for accurate digitization. Our clinical experience suggests that graphically planned T and R results on average in a lower total dose to the

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

    International Nuclear Information System (INIS)

    Dempsey, Claire; Smith, Ryan; Nyathi, Thulani; Ceylan, Abdurrahman; Howard, Lisa; Patel, Virendra; Dam, Ras; Haworth, Annette

    2013-01-01

    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. 3D shape extraction segmentation and representation of soil microstructures using generalized cylinders

    Science.gov (United States)

    Ngom, Ndèye Fatou; Monga, Olivier; Ould Mohamed, Mohamed Mahmoud; Garnier, Patricia

    2012-02-01

    This paper focuses on the modeling of soil microstructures using generalized cylinders, with a specific application to pore space. The geometric modeling of these microstructures is a recent area of study, made possible by the improved performance of computed tomography techniques. X-scanners provide very-high-resolution 3D volume images ( 3-5μm) of soil samples in which pore spaces can be extracted by thresholding. However, in most cases, the pore space defines a complex volume shape that cannot be approximated using simple analytical functions. We propose representing this shape using a compact, stable, and robust piecewise approximation by means of generalized cylinders. This intrinsic shape representation conserves its topological and geometric properties. Our algorithm includes three main processing stages. The first stage consists in describing the volume shape using a minimum number of balls included within the shape, such that their union recovers the shape skeleton. The second stage involves the optimum extraction of simply connected chains of balls. The final stage copes with the approximation of each simply optimal chain using generalized cylinders: circular generalized cylinders, tori, cylinders, and truncated cones. This technique was applied to several data sets formed by real volume computed tomography soil samples. It was possible to demonstrate that our geometric representation supplied a good approximation of the pore space. We also stress the compactness and robustness of this method with respect to any changes affecting the initial data, as well as its coherence with the intuitive notion of pores. During future studies, this geometric pore space representation will be used to simulate biological dynamics.

  18. A review of the recommendations governing quality assurance of ultrasound systems used for guidance in prostate brachytherapy.

    Science.gov (United States)

    Doyle, Andrea Jane; King, Deirdre M; Browne, Jacinta E

    2017-12-01

    Ultrasound guided brachytherapy for the treatment of prostate cancer has become a routine treatment option, due to many benefits including patient recovery and dose localisation [1]; however it is not clear whether the standards which govern the image quality for these systems are adequate. Upon review of the recommended standards for ultrasound systems used in prostate brachytherapy procedures, the recommended tests do not appear to be specific to the clinical application of ultrasound guided prostate brachytherapy. Rather they are generic and similar to those recommended for other clinical applications such as general abdominal scanning [2]. Furthermore, there is growing evidence that these tests should be specific to the clinical application [3,4] in order to gain meaningful data about the performance of the system for the application, and also to detect clinically relevant changes in quality control results. An additional problem is that there are no clinically relevant test phantom recommended for the quality assurance of ultrasound systems used in prostate brachytherapy. The image quality for this application of ultrasound needs to be monitored to ensure consistent levels of confidence in the procedure. This paper reviews the currently recommended test guidelines and test phantoms for ultrasound systems used in prostate brachytherapy from the different standard bodies and professional organisations. A critical analysis of those tests which are most reflective of the imaging and guidance tasks undertaken in an ultrasound guided prostate brachytherapy procedure will also be presented to inform the design of a TRUS quality assurance protocol. Copyright © 2017 Associazione Italiana di Fisica Medica. Published by Elsevier Ltd. All rights reserved.

  19. Artificial neural network based gynaecological image-guided adaptive brachytherapy treatment planning correction of intra-fractional organs at risk dose variation

    Directory of Open Access Journals (Sweden)

    Ramin Jaberi

    2017-12-01

    Full Text Available Purpose : Intra-fractional organs at risk (OARs deformations can lead to dose variation during image-guided adaptive brachytherapy (IGABT. The aim of this study was to modify the final accepted brachytherapy treatment plan to dosimetrically compensate for these intra-fractional organs-applicators position variations and, at the same time, fulfilling the dosimetric criteria. Material and methods : Thirty patients with locally advanced cervical cancer, after external beam radiotherapy (EBRT of 45-50 Gy over five to six weeks with concomitant weekly chemotherapy, and qualified for intracavitary high-dose-rate (HDR brachytherapy with tandem-ovoid applicators were selected for this study. Second computed tomography scan was done for each patient after finishing brachytherapy treatment with applicators in situ. Artificial neural networks (ANNs based models were used to predict intra-fractional OARs dose-volume histogram parameters variations and propose a new final plan. Results : A model was developed to estimate the intra-fractional organs dose variations during gynaecological intracavitary brachytherapy. Also, ANNs were used to modify the final brachytherapy treatment plan to compensate dosimetrically for changes in ‘organs-applicators’, while maintaining target dose at the original level. Conclusions : There are semi-automatic and fast responding models that can be used in the routine clinical workflow to reduce individually IGABT uncertainties. These models can be more validated by more patients’ plans to be able to serve as a clinical tool.

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

    International Nuclear Information System (INIS)

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

    2015-01-01

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

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

    Energy Technology Data Exchange (ETDEWEB)

    Owrangi, A; Jolly, S; Balter, J; Cao, Y; Young, L; Zhu, T; Prisciandaro, J [University of Michigan, Ann Arbor, MI (United States)

    2014-06-01

    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.

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

    International Nuclear Information System (INIS)

    Owrangi, A; Jolly, S; Balter, J; Cao, Y; Young, L; Zhu, T; Prisciandaro, J

    2014-01-01

    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

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

    International Nuclear Information System (INIS)

    Butler, Wayne M.; Merrick, Gregory S.

    2008-01-01

    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

  4. Bronchoscopic brachytherapy in roentgenologically occult cancer of the trachea and bronchus

    Energy Technology Data Exchange (ETDEWEB)

    Ono, Ryosuke; Hirano, Hiroshi (National Cancer Center, Tokyo (Japan). Central Hospital)

    1994-12-01

    Bronchoscopic brachytherapy is a new technique presently being investigated for the treatment of cancer involving the tracheobronchial tree. This paper reports on the potential application of bronchoscopic brachytherapy to the local treatment of cancer of the respiratory tract. Bronchoscopic brachytherapy was performed on 8 patients with roentgenographically occult lung cancer after biopsies proved malignant lesions of the trachea and bronchus in each case. These patients came to the National Cancer Center Hospital during the period from September 1992 to December 1992. Among these 8 cases of malignant lesions of the trachea and bronchus, 5 malignant lesions of the bronchus were diagnosed by bronchoscopic ultrasonography prior to the bronchoscopic brachytherapy, and these 5 patients have completed at least three courses of this therapy carried out by means of a videobronchoscope. Among the 8 cases of malignant lesions of the trachea and bronchus, complete remission was obtained in 7 cases. Of the 8 patients, the death of one patient was caused by amyotrophic lateral sclerosis, while the remaining 7 patients have survived for 13-15 months (14.1 months on average) to date, without showing recurrence or metastasis. As for the complications involved in this treatment, only a light degree of excessive secretions was observed, and there was no abscess formation in any of the cases. (author).

  5. Bronchoscopic brachytherapy in roentgenologically occult cancer of the trachea and bronchus

    International Nuclear Information System (INIS)

    Ono, Ryosuke; Hirano, Hiroshi

    1994-01-01

    Bronchoscopic brachytherapy is a new technique presently being investigated for the treatment of cancer involving the tracheobronchial tree. This paper reports on the potential application of bronchoscopic brachytherapy to the local treatment of cancer of the respiratory tract. Bronchoscopic brachytherapy was performed on 8 patients with roentgenographically occult lung cancer after biopsies proved malignant lesions of the trachea and bronchus in each case. These patients came to the National Cancer Center Hospital during the period from September 1992 to December 1992. Among these 8 cases of malignant lesions of the trachea and bronchus, 5 malignant lesions of the bronchus were diagnosed by bronchoscopic ultrasonography prior to the bronchoscopic brachytherapy, and these 5 patients have completed at least three courses of this therapy carried out by means of a videobronchoscope. Among the 8 cases of malignant lesions of the trachea and bronchus, complete remission was obtained in 7 cases. Of the 8 patients, the death of one patient was caused by amyotrophic lateral sclerosis, while the remaining 7 patients have survived for 13-15 months (14.1 months on average) to date, without showing recurrence or metastasis. As for the complications involved in this treatment, only a light degree of excessive secretions was observed, and there was no abscess formation in any of the cases. (author)

  6. Radiation safety program in high dose rate brachytherapy facility at INHS Asvini

    Directory of Open Access Journals (Sweden)

    Kirti Tyagi

    2014-01-01

    Full Text Available Brachytherapy concerns primarily the use of radioactive sealed sources which are inserted into catheters or applicators and placed directly into tissue either inside or very close to the target volume. The use of radiation in treatment of patients involves both benefits and risks. It has been reported that early radiation workers had developed radiation induced cancers. These incidents lead to continuous work for the improvement of radiation safety of patients and personnel The use of remote afterloading equipment has been developed to improve radiation safety in the delivery of treatment in brachytherapy. The widespread adoption of high dose rate brachytherapy needs appropriate quality assurance measures to minimize the risks to both patients and medical staff. The radiation safety program covers five major aspects: quality control, quality assurance, radiation monitoring, preventive maintenance, administrative measures and quality audit. This paper will discuss the radiation safety program developedfor a high dose rate brachytherapy facility at our centre which may serve as a guideline for other centres intending to install a similar facility.

  7. 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.

  8. Changes in the micromorphology of the corneal subbasal nerve plexus in patients after plaque brachytherapy

    International Nuclear Information System (INIS)

    Zhivov, Andrey; Winter, Karsten; Peschel, Sabine; Stachs, Oliver; Wree, Andreas; Hildebrandt, Guido; Guthoff, Rudolf

    2013-01-01

    To quantify the development of radiation neuropathy in corneal subbasal nerve plexus (SNP) after plaque brachytherapy, and the subsequent regeneration of SNP micromorphology and corneal sensation. Nine eyes of 9 melanoma patients (ciliary body: 3, iris: 2, conjunctiva: 4) underwent brachytherapy (ruthenium-106 plaque, dose to tumour base: 523 ± 231 Gy). SNP micromorphology was assessed by in-vivo confocal microscopy. Using software developed in–house, pre-irradiation findings were compared with those obtained after 3 days, 1, 4 and 7 months, and related to radiation dose and corneal sensation. After 3 days nerve fibres were absent from the applicator zone and central cornea, and corneal sensation was abolished. The earliest regenerating fibres were seen at the one-month follow-up. By 4 months SNP structures had increased to one-third of pre-treatment status (based on nerve fibre density and nerve fibre count), and corneal sensation had returned to approximately two-thirds of pre-irradiation values. Regeneration of SNP and corneal sensation was nearly complete 7 months after plaque brachytherapy. The evaluation of SNP micromorphology and corneal sensation is a reliable and clinically useful method for assessing neuropathy after plaque brachytherapy. Radiation-induced neuropathy of corneal nerves develops quickly and is partly reversible within 7 months. The clinical impact of radiation-induced SNP damage is moderate

  9. Pulsed Dose Rate (PDR - BT) brachytherapy in treatment of breast cancer

    International Nuclear Information System (INIS)

    Skowronek, J.

    2007-01-01

    Breast conserving surgery (BCS) and radiotherapy (EBRT) of the conserved breast became widely accepted in the last decades for the treatment of early invasive breast cancer. The standard technique of RT after breast conservation is to treat the whole breast up to a total dose of 45 to 50 Gy. Initially brachytherapy for breast cancer was used in addition of external radiation to boost a portion of the breast to higher doses. However, over the past 10 years, the application of brachytherapy in breast cancer has changed. In early stage breast cancer, research has shown that the area that requires radiation treatment to prevent the cancer from returning is the breast tissue that surrounds the area where the initial cancer was removed. Because this typically includes only a part of the breast, brachytherapy is now being used to treat the targeted portion of the breast and as a result allows accelerated delivery of the radiation dose so that treatment is completed in four to five days. Another indications for PDR - BT as a part of treatment in locally advanced breast cancer or as a palliative treatment are discussed in the paper, too. Preliminary results with PDR - BT boost technique are promising. However, more experience and longer follow-up are required to define whether these methods might improve local tumor control for breast cancer patients. In this article the current status, indications, technical aspects and published results of PDR brachytherapy (PDR - BT) in breast cancer treatment are reviewed. (author)

  10. The need for international standardization in clinical beta dosimetry for brachytherapy

    International Nuclear Information System (INIS)

    Quast, U.; Boehm, J.; Kaulich, T.W.

    2002-01-01

    Beta radiation has found increasing interest in radiotherapy. Besides the curative treatment of small and medium-sized intraocular tumors by means of ophthalmic beta radiation plaques, intravascular brachytherapy has proven to successfully overcome the severe problem of restenosis after interventional treatment of arterial stenosis in coronaries and peripheral vessels in many clinical trials with a large number of patients. Prior to initiating procedures applying beta radiation in radiotherapy, however, there is a common need to specify methods for the determination and specification of the absorbed dose to water or tissue and their spatial distributions. The IAEA-TECDOC-1274 Calibration of photon and beta ray sources used in brachytherapy (2002) is a help for photon brachytherapy calibration. But, for beta seed and line sources, IAEA recommends well type ionization chambers as working standards which are far from measuring absorbed dose to water of the radiation clinically used. Although the application of such working standards seems to be more precise, large errors can occur when the medical physicist has to convert the calibration data to absorbed dose to water of the beta radiation emitted. The user must believe that the source is equally activated and that the manufacturer did not change the design and construction of the source encapsulation. With the DGMP Report 16 (2001) Guidelines for medical physical aspects of intravascular brachytherapy a very detailed code of practice is given, especially for the calibration and clinical dosimetry of intravascular beta radiation sources. As there is a global need for standardization in clinical dosimetry for intravascular brachytherapy utilizing beta radiation, the DIN-NAR, the German committee on standardization in radiology, task group dosimetry, has initiated an international adhoc working group for a new ISO work item proposal on the standardization of procedures in clinical dosimetry to guarantee reliable

  11. Orbital rhabdomyosarcoma of the child: the role of PDR brachytherapy in eye preservation

    International Nuclear Information System (INIS)

    Kovacs, G.; Rochels, R.; Mehdorn, H.M.; Werner, J.; Wilhelm, R.; Kohr, P.; Kimmig, B. N.

    1996-01-01

    Material and Methods: There were four children (8-7-5 years and(15(12)) months old) with recurrent/primary embryonal rhabdomyosarcoma treated with curative intention by peroperative PDR boost brachytherapy in combination with radio-chemotherapy and/or surgery. PDR brachytherapy according to the Kiel protocol: daily five pulses, two hours each, with 1 Gy on the reference isodose which is usually 2-3 mm close to the applicator surface. CT simulation based conformal treatment planning was carried out in each case. The implant was done intraoperatively using the free-hand plastic tube method, after a macroscopically complete excision of the tumor. Due to treatment planning individual target volume, eye with N, opticus and bone structures, as well as the applicators and other regions of interest were visualized. Manual volume optimisation was practiced and natural volumen-dose histograms were analysed in 'classic' graphic mode as well as in a special colour coded three-dimensional visualization in cine mode on the screen. One child received, three months before the recurrence was operated, 50 Gy hyperfractionated external beam radiation (2 Gy fractions) and was irradiated with 20 Gy brachytherapy in four days. The second patient received ten days after 20 Gy brachytherapy 32 Gy hyperfractionated external beam radiation. The third child (external beam treatment outside of our clinic), received conventional fractionated irradiation with 1.6 Gy fraction dose instead of a prescribed hyperfractionated external beam therapy and her brachytherapy dose was 25 Gy. At the (15(12)) months old child with primary embryonal rhabdomyosarcoma we applied 20 Gy brachytherapy and 24 Gy hyperfractionated external beam irradiation. All patients received multidrug chemotherapy according to the German Study Protocol (CWS-91). Results: Follow-up is 34, 28, 22, and 6 months for recurrent embryonal rhabdomyosarcoma patients (stand February 96). We observed at 9 months one rhabdomyosarcoma

  12. Conformational episcleral brachytherapy in ocular tumors

    International Nuclear Information System (INIS)

    Goset, Karen; Barriga, Hernan; Guevara, Juan; Zelada, Gabriel; Badinez, Leonardo; Gonzalez, German

    2000-01-01

    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

  13. BrachyTPS -Interactive point kernel code package for brachytherapy treatment planning of gynaecological cancers

    International Nuclear Information System (INIS)

    Thilagam, L.; Subbaiah, K.V.

    2008-01-01

    Brachytherapy treatment planning systems (TPS) are always recommended to account for the effect of tissue, applicator and shielding material heterogeneities exist in Intracavitary brachytherapy (ICBT) applicators. Most of the commercially available brachytherapy TPS softwares estimate the absorbed dose at a point, only taking care of the contributions of individual sources and the source distribution, neglecting the dose perturbations arising from the applicator design and construction. So the doses estimated by them are not much accurate under realistic clinical conditions. In this regard, interactive point kernel rode (BrachyTPS) has been developed to perform independent dose calculations by taking into account the effect of these heterogeneities, using two regions build up factors, proposed by Kalos. As primary input data, the code takes patients' planning data including the source specifications, dwell positions, dwell times and it computes the doses at reference points by dose point kernel formalisms, with multi-layer shield build-up factors accounting for the contributions from scattered radiation. In addition to performing dose distribution calculations, this code package is capable of displaying an isodose distribution curve into the patient anatomy images. The primary aim of this study is to validate the developed point kernel code integrated with treatment planning systems against the other tools which are available in the market. In the present work, three brachytherapy applicators commonly used in the treatment of uterine cervical carcinoma, Board of Radiation Isotope and Technology (BRIT) made low dose rate (LDR) applicator, Fletcher Green type LDR applicator and Fletcher Williamson high dose rate (HDR) applicator were studied to test the accuracy of the software

  14. Cost minimization analysis of high-dose-rate versus low-dose-rate brachytherapy in endometrial cancer

    International Nuclear Information System (INIS)

    Pinilla, James

    1998-01-01

    Purpose: Endometrial cancer is a common, usually curable malignancy whose treatment frequently involves low-dose-rate (LDR) or high-dose-rate (HDR) brachytherapy. These treatments involve substantial resource commitments and this is increasingly important. This paper presents a cost minimization analysis of HDR versus LDR brachytherapy in the treatment of endometrial cancer. Methods and Materials: The perspective of the analysis is that of the payor, in this case the Ministry of Health. One course of LDR treatment is compared to two courses of HDR treatment. The two alternatives are considered to be comparable with respect to local control, survival, and toxicities. Labor, overhead, and capital costs are accounted for and carefully measured. A 5% inflation rate is used where applicable. A univariate sensitivity analysis is performed. Results: The HDR regime is 22% less expensive compared to the LDR regime. This is $991.66 per patient or, based on the current workload of this department (30 patients per year) over the useful lifetime of the after loader, $297,498 ov