نتایج جستجو برای: presage

تعداد نتایج: 364  

Alireza Kamali Asl, Mohammad Hassan Zahmatkesh Saeid Bagheri Zeynab Sanjabi

Introduction: Different dosimetric modalities (e.g., ionization chambers, semiconductors, TLDs, radiographic films) often have some problems determining isodose curves and percentage depth doses in high dose gradient regions. Research has been ongoing to develop portable high resolution dosimetry devices with accurate absolute dosimetry capabilities and easy data analysis. The ‘PRESAGE’ dosimet...

Journal: :iranian journal of medical physics 0
zeynab sanjabi m.sc. of radiation medicine dept., shahid beheshti university, tehran, iran. alireza kamali asl assistant professor, nuclear engineering dept., shahid beheshti university, tehran, iran mohammad hassan zahmatkesh associate professor, shahid beheshti university, evin, tehran, iran saeid bagheri m.sc. in medical physics, shahid beheshti university, tehran, iran

introduction: different dosimetric modalities (e.g., ionization chambers, semiconductors, tlds, radiographic films) often have some problems determining isodose curves and percentage depth doses in high dose gradient regions. research has been ongoing to develop portable high resolution dosimetry devices with accurate absolute dosimetry capabilities and easy data analysis. the ‘presage’ dosimet...

Journal: :Medical physics 2006
Pengyi Guo John Adamovics Mark Oldham

There is a pressing need for a practical three-dimensional (3D) dosimetry system, convenient for clinical use, and with the accuracy and resolution to enable comprehensive verification of the complex dose distributions typical of modern radiation therapy. Here we introduce a dosimetry system that can achieve this challenge, consisting of a radiochromic dosimeter (PRESAGE) and a commercial optic...

2013
T Juang J Newton M Niebanck R Benning J Adamovics M Oldham

PRESAGE® is a solid radiochromic dosimeter consisting of a polyurethane matrix, a triarylmethane leuco dye, and a trihalomethane initiator. Varying the composition and/or relative amounts of these constituents can affect the dose sensitivity, post-irradiation stability, and physical properties of the dosimeter. This allows customisation of PRESAGE® to meet application-specific requirements, suc...

Journal: :Nucleic acids research 1999
Steven E. Brenner Derren Barken Michael Levitt

The PRESAGE database is a collaborative resource for structural genomics. It provides a database of proteins to which researchers add annotations indicating current experimental status, structural predictions and suggestions. The database is intended to enhance communication among structural genomics researchers and aid dissemination of their results. The PRESAGE database may be accessed at htt...

2013
C-S Wuu Y Xu X Qian J Adamovics E Cascio H-M Lu

The objective of this study is to assess the feasibility of using PRESAGE dosimeters for proton pencil beam dosimetry. Two different formulations of phantom materials were tested for their suitability in characterizing a single proton pencil beam. The dosimetric response of PRESAGE was found to be linear up to 4Gy. First-generation optical CT scanner, OCTOPUS was used to implement dose distribu...

Journal: :Medical physics 2014
R Lafratta J Yang N Sahoo S Tucker D Followill G Ibbott

PURPOSE To compare gamma calculations from 2D and 3D dosimetry measurements for phantom quality assurance. METHODS An IROC Houston (RPC) head and neck phantom was irradiated with a 9 beam IMRT plan using two inserts: a TLD and film insert and a PRESAGE insert. Both inserts were irradiated 3 times. The film and PRESAGE doses were scaled to the TLD dose and 2D gamma calculations were made in th...

2012
N. Annabell N. Yagi K. Umetani C. Wong M. Geso

Synchrotron-generated microbeam radiotherapy holds great promise for future treatment, but the high dose gradients present conventional dosimetry with a challenge. Measuring the important peak-to-valley dose ratio (PVDR) of a microbeam-collimated synchrotron source requires both a dosimeter and an analysis method capable of exceptional spatial resolution. The PVDR is of great interest since it ...

Journal: :Journal of physics. Conference series 2010
Z Wang A Thomas J Newton G Ibbott J Deasy M Oldham

Achieving adequate verification and quality-assurance (QA) for radiosurgery treatment of trigeminal-neuralgia (TGN) is particularly challenging because of the combination of very small fields, very high doses, and complex irradiation geometries (multiple gantry and couch combinations). TGN treatments have extreme requirements for dosimetry tools and QA techniques, to ensure adequate verificatio...

Journal: :Physics in medicine and biology 2011
A T Abdul Rahman Elke Bräuer-Krisch Thierry Brochard John Adamovics S K Clowes David Bradley Simon J Doran

Optical computed tomography (CT), in conjunction with radiochromic gels and plastics, shows great potential for radiation therapy dose verification in 3D. However, an effective quality assurance (QA) regime for the various scanners currently available still remains to be developed. We show how the favourable properties of the PRESAGE® radiochromic polymer may be exploited to create highly sophi...

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