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PubMed Journals Articles About "Varian Medical Systems Signs Brachytherapy Applicator Distribution Agreement" RSS

06:18 EST 25th November 2017 | BioPortfolio

Varian Medical Systems Signs Brachytherapy Applicator Distribution Agreement PubMed articles on BioPortfolio. Our PubMed references draw on over 21 million records from the medical literature. Here you can see the latest Varian Medical Systems Signs Brachytherapy Applicator Distribution Agreement articles that have been published worldwide.

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Showing "Varian Medical Systems Signs Brachytherapy Applicator Distribution Agreement" PubMed Articles 1–25 of 25,000+

Varian HDR surface applicators - commissioning and clinical implementation.

The purpose of this study was to validate the dosimetric performance of Varian surface applicators with the source vertically positioned and develop procedures for clinical implementation. The Varian surface applicators with the source vertically positioned provide a wide range of apertures making them clinically advantageous, though the steep dose gradient in the region of 3-4 mm prescription depth presents multiple challenges. The following commissioning tests were performed: 1) verification of functional...


A generic TG-186 shielded applicator for commissioning model-based dose calculation algorithms for high-dose-rate (192) Ir brachytherapy.

A joint working group was created by the American Association of Physicists in Medicine (AAPM), the European Society for Radiotherapy and Oncology (ESTRO), and the Australasian Brachytherapy Group (ABG) with the charge, among others, to develop a set of well-defined test case plans and perform model-based dose calculation algorithms (MBDCA) dose calculations and comparisons. Its main goal is to facilitate a smooth transition from the AAPM Task Group No. 43 (TG-43) dose calculation formalism, widely being us...

Direction Modulated Brachytherapy (DMBT) for Treatment of Cervical Cancer: A Planning Study with 192Ir, 60Co, and 169Yb HDR Sources.

To evaluate plan quality of a novel MRI-compatible direction modulated brachytherapy (DMBT) tandem applicator using 192Ir, 60Co, and 169Yb HDR brachytherapy sources, for various cervical cancer high-risk clinical target volumes (CTVHR ).


Gafchromic film dosimetry of a new HDR  192Ir brachytherapy source.

High-dose-rate (HDR) brachytherapy is a popular modality for treating cancers of the prostate, cervix, endometrium, breast, skin, bronchus, esophagus, and head and neck as well as soft-tissue sarcomas. Because of different source designs and licensing issues, there is a need for specific dosimetry dataset for each HDR source model. The main objective of the present work is to measure 2D relative dose distribution around a new prototype  192Ir source, referred to as IRAsource-HDR, in PMMA phantom in the fr...

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

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 t...

Image-guided navigation systems for interstitial brachytherapy.

Interstitial brachytherapy has shown quite promising therapeutic effects in the treatment of tumors in various body regions. Prior to the navigation techniques with quantitative imaging feedback during the procedure, the safety and accuracy of interstitial brachytherapy mainly depended upon the operator's experience, spatial skills and mind reconstruction of the anatomical structures. Different navigation systems have been reported to be experimented on various phantoms and clinically applied in the brachyt...

Performance evaluation of a collapsed cone dose calculation algorithm for HDR Ir-192 of APBI treatments.

Most dose calculations for HDR brachytherapy treatments are based on the AAPM-TG43 formalism. Because patient's anatomy, heterogeneities and applicator shielding are not considered, the dose calculation based on this formalism is inaccurate in some cases. Alternatively, Collapsed Cone (CC) methods as well as Monte Carlo (MC) algorithms belong to the model based dose calculation algorithms, which are expected to improve the accuracy of calculated dose distributions. In this work, the performance of a CC algo...

Secondary cancer-incidence risk estimates for external radiotherapy and high-dose-rate brachytherapy in cervical cancer: phantom study.

This study was designed to estimate radiation-induced secondary cancer risks from high-dose-rate (HDR) brachytherapy and external radiotherapy for patients with cervical cancer based on measurements of doses absorbed by various organs. Organ doses from HDR brachytherapy and external radiotherapy were measured using glass rod dosimeters. Doses to out-of-field organs were measured at various locations inside an anthropomorphic phantom. Brachytherapy-associated organ doses were measured using a specialized pha...

A dosimetric comparison of copper and Cerrobend electron inserts.

The purpose of this work was to evaluate differences in dose resulting from the use of copper aperture inserts compared to lead-alloy (Cerrobend) aperture inserts for electron beam therapy. Specifically, this study examines if copper aperture inserts can be used clinically with the same commissioning data measured using lead-alloy aperture inserts. The copper inserts were acquired from .decimal, Inc. and matching lead-alloy, Cerrobend inserts were constructed in-house for 32 combinations of nine square inse...

Semiconductor real-time quality assurance dosimetry in brachytherapy.

With the increase in complexity of brachytherapy treatments, there has been a demand for the development of sophisticated devices for delivery verification. The Centre for Medical Radiation Physics (CMRP), University of Wollongong, has demonstrated the applicability of semiconductor devices to provide cost-effective real-time quality assurance for a wide range of brachytherapy treatment modalities. Semiconductor devices have shown great promise to the future of pretreatment and in vivo quality assurance in...

Challenges in MR-only seed localization for postimplant dosimetry in permanent prostate brachytherapy.

An MR-only postimplant dosimetry workflow for low dose rate (LDR) brachytherapy could reduce patient burden, improve accuracy, and improve cost efficiency. However, localization of brachytherapy seeds on MRI scans remains a major challenge for this type of workflow. In this study, we propose and validate an MR-only seed localization method, and identify remaining challenges.

Can reference images improve interobserver agreement in reporting liver fibrosis?

Staging of fibrosis in medical liver biopsies has inherent interobserver variability. There are a number of disease-specific scoring systems available. While recognising the importance of these scoring systems, there is scope to consider how concordance amongst histopathologists could be improved using a generic fibrosis staging system.Using virtual slides, we approached both specialist liver histopathologists and general histopathologists from the UK to assess the degree of fibrosis against a proposed four...

Influence of patient mispositioning on SAR distribution and simulated temperature in regional deep hyperthermia.

Patient positioning plays an important role in regional deep hyperthermia to obtain a successful hyperthermia treatment. In this study, the influence of possible patient mispositioning was systematically assessed on specific absorption rate (SAR) and temperature distribution. With a finite difference time domain approach, the SAR and temperature distributions were predicted for six patients at 312 positions. Patient displacements and rotations as well as the combination of both were considered inside the Si...

Permanent prostate brachytherapy pubic arch evaluation with diagnostic MRI.

Pubic arch interference (PAI), when it occurs, is often a limiting factor for patients pursuing brachytherapy treatment of prostate cancer. Pre-brachytherapy pubic arch evaluation is often performed by CT or transrectal ultrasound (TRUS), but MRI has increasingly replaced these modalities for prostate cancer evaluation. The purpose of this study was to determine if staging MRI could be used to evaluate PAI and compare it with these other imaging methods.

Anatomy-based definition of point A utilizing three-dimensional volumetric imaging approach for high-dose-rate (HDR) intracavitary brachytherapy dose prescription when treating cervical cancer using limited resources.

This study was designed to determine whether volumetric imaging could identify consistent alternative prescription methods to Manchester/point A when prescribing radiation dose in the treatment of cervical cancer using HDR intracavitary brachytherapy (ICBT). One hundred and twenty-five treatment plans of 25 patients treated for carcinoma of the cervix were reviewed retrospectively. Each patient received 5 fractions of HDR ICBT following initial cisplatin-based pelvic chemoradiation, and radiation dose was o...

Clinical outcomes with MRI-guided image-based brachytherapy in cervical cancer: An institutional experience.

To evaluate the long-term disease control and toxicity to the organs at risk after dose-escalated image-based adaptive brachytherapy (BT) in cervical cancer.

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

The aim of the present Monte Carlo study is to evaluate the variation of energy deposition in healthy tissues in the human eye which is irradiated by brachytherapy sources in comparison with the resultant dose increase in the gold nanoparticle (GNP)-loaded choroidal melanoma. The effects of these nanoparticles on normal tissues are compared between 103Pd and 125I as two ophthalmic brachytherapy sources. Dose distribution in the tumor and healthy tissues has been taken into account for both brachytherapy sou...

Multisource Rotating Shield Brachytherapy Apparatus for Prostate Cancer.

Our purpose is to present a novel multisource rotating shield brachytherapy (RSBT) apparatus for the simultaneous precise angular and linear positioning of partially shielded (153)Gd brachytherapy sources in interstitial needles for the treatment of locally advanced prostate cancer. It is designed to lower the dose to nearby healthy tissues, the urethra in particular, relative to conventional high-dose-rate brachytherapy techniques.

Identification of the suitable leaf margin for liver stereotactic body radiotherapy with flattening filter-free beams.

The purpose of this study is to identify the suitable leaf margin for liver stereotactic body radiotherapy (SBRT) with flattening filter-free (FFF) beams, as compared with that with flattening filter (FF) beams. SBRT treatment planning for 10 patients with liver cancer was performed using 10-MV FFF and FF beams obtained from a Varian TrueBeam (Varian Medical Systems, Palo Alto, CA) linear accelerator. Each plan was generated with the leaf margin to the planning target volume (PTV) ranging from -3 to 5 mm....

The role of (125)I interstitial brachytherapy for inoperable parotid gland carcinoma.

The treatment of inoperable parotid gland carcinoma is challenging and controversial. The purpose of this paper was to present our experience in treating this malignancy using (125)I interstitial brachytherapy.

Verification measurements of an eMC algorithm using a 2D ion chamber array.

The aim of this study was to assess the suitability of the Im'RT MatriXX 2D ion chamber array for performing verification measurements on the Varian Eclipse electron Monte Carlo (eMC) algorithm for a range of clinical energies (6, 12, and 20 MeV) on a Varian 2100iX linear accelerator. Firstly, the suitability of the MatriXX for measuring percentage depth doses (PDD) in water was assessed, including characterization of the inherent buildup found in the MatriXX. Secondly the suitability of the MatriXX for mea...

Preliminary Determination of Activation Products for a Varian Truebeam Linear Accelerator.

Medical linear accelerators used to treat various forms of cancers are operated at a number of different energies. A by-product of the high-energy photons produced by accelerators is activation of components within the machine itself and its surrounding bunker. The activation products pose radiological and regulatory challenges during the operation of the accelerator as well as when it is time for final decommissioning. The Varian TrueBeam is a new state-of-the-art linear accelerator now operating in the Ca...

Manual vs. automated implantation of seeds in prostate brachytherapy: Oncologic results from a single-center study.

The objective of this study was to study survival and tolerance of prostate cancer patients treated with (125)I permanent interstitial brachytherapy by automated vs. manual implantation of seeds.

Going the distance: validation of Acuros and AAA at an extended SSD of 400 cm.

Accurate dose calculation and treatment delivery is essential for total body irradiation (TBI). In an effort to verify the accuracy of TBI dose calculation at our institution, we evaluated both the Varian Eclipse AAA and Acuros algorithms to predict dose distributions at an extended source-to-surface distance (SSD) of 400 cm. Measurements were compared to calculated values for a 6 MV beam in physical and virtual phantoms at 400 cm SSD using open beams for both 5×5 and 40×40 cm2 field sizes. Inline and c...

Automatic Torso Detection in Images of Preterm Infants.

Imaging systems have applications in patient respiratory monitoring but with limited application in neonatal intensive care units (NICU). In this paper we propose an algorithm to automatically detect the torso in an image of a preterm infant during non-invasive respiratory monitoring. The algorithm uses normalised cut to segment each image into clusters, followed by two fuzzy inference systems to detect the nappy and torso. Our dataset comprised overhead images of 16 preterm infants in a NICU, with uncontro...


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